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Health Services Utilization and

Medical Costs Among Medicare Atrial

Fibrillation Patients /

September 2010

Table of Contents

Executive Summary .................................... 2

Background .................................................. 7

Methodology .............................................. 12

Results ........................................................ 18

Limitations ................................................ 30

Conclusions ................................................ 33

Appendix

A ................................................................ 37

B ................................................................ 39

C ............................................................... 42

D .............................................................. 44

E ............................................................... 45

Glossary of Key Terms ............................. 46

Endnotes .................................................... 47

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Executive Summary

Background/Objective Chronic diseases such as diabetes, cancer, and cardiovascular disease are the leading cause of death and disability in the United States. Atrial Fibrillation (AFib) is one type of chronic cardiovascular disease that is highly prevalent in the Medicare population. Previous studies have shown that AFib patients use more healthcare services than patients without AFib.1,2 As this condition is estimated to cost the Medicare program over $15.7 billion per year,3

This issue brief is the second in a series in which Avalere examines the burden of AFib on the Medicare program. The purpose of this original analysis is to examine use of healthcare services, including inpatient and outpatient services, physician services, and emergency department (ED) services, as well as medical costs among Medicare AFib patients following an initial hospitalization for AFib. In the first paper, “Medicare and Atrial Fibrillation: Consequences in Cost and Care” (2009), Avalere described the clinical and economic burden of AFib on the Medicare program, characterized the current state of quality improvement efforts, and identified potential quality improvement strategies.

it is important to understand the key components of AFib patient health services utilization and medical costs.

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Methodology

Avalere conducted a retrospective database analysis based on Medicare’s five percent Standard Analytic Files (SAFs) for 2004-2008. The SAFs are publicly available files which are commonly used by researchers to examine utilization and cost patterns in the Medicare population. The five percent SAFs are a nationally representative sample of ‘final action’ claims data for the Medicare beneficiary population.5,6

We identified a cohort of Medicare patients with AFib and constructed an analytic file linking the inpatient, outpatient, and physician claims files for these patients. Our study population included patients with a primary diagnosis of AFib during an ‘initial’ or ‘index’ hospitalization. For AFib patients in our study, we examined the utilization of, and costs associated with hospital inpatient and outpatient services, physician services, and ED services. We tracked the utilization and costs of these services during the quarter of the index hospitalization and the four quarters subsequent to the index hospitalization.

Health Services Utilization and Medical Costs Among Medicare Atrial Fibrillation Patients | 3

We refer to these five quarters as the follow-up period. Medicare payments are used as a proxy for medical costs; all costs are reported in 2009 US dollars.

Study Results AFib patients in our study had multiple comorbid conditions There were 14,174 patients that had a primary diagnosis of AFib during their index hospitalization. The average age of these patients at the time of their index hospitalization was 76; 60 percent of patients are female, and most of them are white (92 percent). Patients included in this analysis had several comorbid conditions in addition to AFib, including hypertension, other cardiovascular conditions, and diabetes.

Overall average medical costs among AFib patients in this study were nearly $24,000 per patient during the follow-up period The total medical costs of treating AFib patients over the follow-up period averaged almost $24,000 per beneficiary. Sixty-two percent ($14,887) of these costs were for inpatient services. Furthermore, 63 percent of the inpatient services costs ($9,412) were related to readmission costs.

The costs observed in our study are higher than in some published reports,7,8 but are comparable to those reported by Lee and colleagues.9 Using the five percent Medicare SAFs, Lee reported average one-year healthcare costs in a cohort of AFib patients to be $23,750, compared to our finding of an average per-patient cost of $23,899 over five quarters. Although these costs appear similar between the Lee study and our analysis, the two studies were based on different AFib patient populations. Lee and colleagues focused on patients newly diagnosed with AFib, 87 percent of whom were diagnosed in the outpatient setting; while our analysis included patients who had an inpatient hospitalization for AFib. In addition, Lee et al. included medical costs from skilled nursing facilities (SNF), home healthcare, durable medical equipment, and hospice in their analysis, whereas we did not include these services in our analysis.10

In addition, the total AFib costs per patient for five quarters reported in our analysis are similar to those reported in studies of other costly cardiovascular conditions. For example:

According to two studies based on managed care data, average one-year medical costs for patients with acute coronary syndrome, including

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myocardial infarction and unstable angina, ranged from $22,500 to $41,000. 11, 12

A recent study analyzing costs and health resource utilization for Medicare patients with heart failure and diabetes, reported aggregated two-year mean costs of $32,676 for patients with diabetes and heart failure and $22,230 for patients with heart failure only.

13

AFib patients in our sample had high hospital outpatient and physician services utilization

AFib patients in our analysis were frequent users of hospital outpatient and physician health services. Hospital outpatient visits include services provided in a hospital setting that do not require an overnight stay. Physician encounters may occur in various settings, including a physician’s office, the hospital inpatient or outpatient settings, the ED, laboratory, or other sites of service (e.g., SNF).

Most of the patients had at least one hospital outpatient visit (90 percent) and at least one encounter with a physician (98 percent). These patients had an average of 12 hospital outpatient visits and 67 physician encounters during the follow-up period. Approximately 46 percent of these physician encounters (n=30) occurred in the physician office setting, and 31 percent of physician visits in all settings of care were for cardiovascular-related reasons. Related, across all settings of care, cardiology (20 percent) was the leading physician specialty caring for AFib patients, followed by internal medicine (16 percent).

The cumulative cost per beneficiary with at least one hospital outpatient visit averaged $2,972. The cumulative cost per beneficiary among those with at least one physician encounter averaged $6,471.

Sixty-one percent of the AFib patients in our study visited the emergency department during follow-up period ED utilization was an essential part of the utilization pattern of AFib patients as well; 61 percent of the patients visited the ED at least once in the follow-up period. On average, these patients went to the ED three times during this period. Twenty-nine percent of AFib patient ED visits were for cardiovascular-related reasons.


AFib patients in our study were often readmitted multiple times and shortly after the initial hospitalization More than half (52 percent) of the 14,174 AFib patients in our analysis were readmitted to an inpatient hospital at least once during the follow-up period. Furthermore, 12 percent of patients were readmitted three or more times. AFib was the primary diagnosis in 15 percent of readmissions. A large percentage of hospital readmissions occurred relatively soon after the index hospitalization. Specifically, we found that: about 25 percent of readmissions occurred within the same quarter as the

index hospitalization; and that 23 percent of readmissions occurred in the quarter after the index

hospitalization.

Cardiovascular-related conditions were key causes of hospital readmissions among AFib patients in our study Based on an examination of Diagnosis Related Group (DRG) assignments, we found that 48 percent of hospital readmissions identified in our analysis were related to cardiovascular conditions such as heart failure and shock, hypertension, and chest pain. An examination of the cardiovascular-related readmission International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes shows that 31 percent of these readmissions listed AFib (ICD-9-CM 427.31) in the primary position on the claim.

AFib is often reported as a comorbid condition that may influence healthcare utilization and costs We also found that AFib is more often reported as a comorbidity to other conditions than as a primary diagnosis. Furthermore, when patients had AFib as a secondary diagnosis, the total medical costs during the follow-up period were higher ($33,200) than when patients had AFib as a primary diagnosis ($23,899). This suggests that AFib as a comorbid condition may exacerbate primary conditions, influencing the utilization patterns and costs of care for those conditions. Further research to fully understand the clinical and economic impact of AFib as a comorbid condition would be valuable.

Conclusions This retrospective study assessed health resource utilization and associated costs over a five quarter period following an index hospitalization for AFib in a well-defined cohort of Medicare patients. The results provide valuable information on a unique subset of the AFib patient population that has not been

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well characterized in the literature. The findings highlight the economic burden of AFib on the Centers for Medicare & Medicaid Services (CMS) and the overall healthcare system. The findings also emphasize the need for improved management strategies to help reduce the high health services utilization and medical costs in all settings of care for Medicare AFib patients. As the Medicare population continues to grow and the prevalence of AFib increases, reforms aimed at additional research, quality improvement, and cost management will be critical to support the advancement of AFib treatment, improve patient outcomes, and reduce costs for the Medicare program.


Background

AFib is a prevalent cardiovascular disease in the Medicare population Chronic diseases such as diabetes, cancer, and cardiovascular disease are the leading cause of death and disability in the United States. AFib is one type of chronic cardiovascular disease which is highly prevalent in adults over age 65.14

The condition causes its patients to have an irregular heartbeat. Specifically, it is caused by disorganized electrical activity in the top chambers (the atria) of the heart, resulting in a quivering motion of the atria instead of a normal, organized pumping motion. This quiver, or fibrillation, causes a heartbeat that can be more than twice that of a normal heart rate at rest.15 It may also lead to stagnation of blood flow in the atria, which can cause blood clots and stroke. AFib usually occurs due to the presence of other cardiac conditions such as hypertension, heart failure, coronary artery disease, and heart valve disease. However, it can also be caused by conditions that do not involve the heart such as pneumonia or thyroid disorders.16

As the most common arrhythmia in the United States, AFib affects more than 2.5 million adults, 80 percent of whom are 65 years and older. In the next 40 years, the prevalence of AFib is projected to more than double to 5.6 million adults.

17 AFib accounts for one third of hospitalizations for an irregular heartbeat.18

Figure 1 AFib is increasingly prevalent in the United States

Figure 1 shows historical and projected growth of AFib prevalence in the United States.

2.08 2.26 2.44

2.66 2.943.33

3.84.34

4.785.16 5.42 5.61

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

1995 2000 2005 2010 2015 2020 2025 2030 2035 2040 2045 2050

Adults with AFib(in Millions)

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Description of Disease Description of Disease

What is AFib? AFib refers to an irregular rhythm in the heart (arrhythmia) due to disorganized electrical activity in the upper chambers of the heart (the atria), resulting in irregular impulses being sent to the lower chambers of the heart (the ventricles) which in turn generates an irregular heartbeat.19 The atrial cells fire at rates of 400-600 times per minute, causing the muscles in the atria to quiver, or fibrillate, instead of normally contracting.20 As a result, a typical heart rate of a person with AFib can be very rapid—up to 150 beats per minute or higher, compared to a normal heart rate of 60-100 beats per minute at rest.21 AFib episodes may occur periodically, and last anywhere from minutes up to a week, longer than a week, requiring intervention by a healthcare professional to restore normal heart rhythm (persistent AFib), (paroxysmal AFib) or may become chronic (permanent AFib).22

What are the risk factors for AFib?

Risk factors for AFib may include the presence of several other comorbid conditions, including hypertension, congestive heart failure (HF), obesity, diabetes, mitral valve disease, pericarditis, chronic obstructive pulmonary disease, and sleep apnea. History of myocardial infarction is also a risk factor for AFib.23

What are the symptoms of AFib?

AFib may be asymptomatic, or include symptoms such as palpitations (a sudden fluttering feeling in the chest), anxiety, shortness of breath, weakness, and difficulty exercising, chest pain, sweating, dizziness, or fainting.24

How is AFib treated?

AFib treatment depends on the cause and type of AFib that is diagnosed. The goal of AFib treatment is to either restore normal heart rhythm or control the heart rate, and to prevent stroke. Treatment options range from medications alone (anti-coagulants, anti-arrhythmics, and rate control medications) to more aggressive interventions, which may include electrical cardio-version, cardiac ablation, pacemaker implantation, and surgery.25

AFib patients have several comorbid conditions

AFib patients often have several age-related comorbidities such as valvular heart disease, HF, coronary artery disease, diabetes, and hypertension.26 In a 2009 study, researchers found that AFib is common among patients with diabetes. Specifically, they found that AFib was 44 percent more prevalent and 38 percent


more likely to develop among patients with diabetes.27 Furthermore, AFib significantly increases the risk of stroke and heart disease, both of which are leading causes of death in the United States.28 As a result, AFib patients with heart disease have higher mortality rates compared to patients with normal heart rhythm.29

AFib is also associated with significant impairments in patient quality of life.

30 Patients’ daily functioning may be hindered by symptoms such as palpitations (a sudden “fluttering” feeling in the chest), shortness of breath, weakness, chest pain, sweating, dizziness, and fainting.31 AFib patients also typically suffer from impairments in mental health and social functioning,32 such as high levels of anxiety.33

AFib patients use more healthcare services than patients without AFib

Studies have shown that AFib patients utilize many types of healthcare services including those associated with the inpatient hospital, outpatient settings, and the emergency department. Inpatient hospital services have been of particular interest. A study based on the National Hospital Discharge Survey demonstrated that AFib hospitalizations tripled from 1985 to 1999.34

28 percent of AFib patients versus seven percent of non-AFib patients have 3 hospital admissions;

Since then, researchers have continued to find that AFib patients are commonly readmitted to the hospital and use high levels of other types of healthcare services. For example, a 2008 study of Medicare beneficiaries showed that patients with AFib required significantly more healthcare services compared to those without AFib. Specifically, during the first year following an AFib diagnosis:

14 percent of AFib patients versus three percent of non-AFib patients have 3 emergency room visits; and,

72 percent of AFib patients versus 61 percent of non-AFib patients have 3 outpatient visits.35

In a retrospective study of managed care patients (under age 65), Kim et al. (2009) found about 10 to 12 percent of those with AFib were readmitted to the hospital within the first year following their initial AFib hospitalization. About 66 percent of these hospitalizations occurred within six months of the initial AFib hospitalization, while 20 percent of these readmissions occurred within the first month. Kim and colleagues suggest that an even higher rate of readmissions would occur in the Medicare population.

36 Yet another study that focused on the

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timing of the hospitalization showed the likelihood of a hospitalization was the highest within the first year after the diagnosis of AFib.37

AFib costs Medicare more than $15.7 billion annually

Medicare absorbs the majority of the clinical and economic burden of caring for AFib patients. This is not surprising considering that this diagnosis is more common in an older population, and that the complications associated with AFib increase with age. An Avalere analysis of public and private payer survey data identifies Medicare as the primary payer of AFib across all settings of care (Figure 2).

Figure 2 Medicare is the primary payer for AFib across all settings of care

Avalere Health analysis of data from the National Hospital Discharge Survey, National Ambulatory Medical Care Survey and National Ambulatory Medical Care Survey Outpatient Department and Emergency Department for years 1997–2006 for ICD-9 diagnosis code 427.31.

In a 2009 study of managed care patients, researchers estimated that the total hospitalization and outpatient cost of treating AFib patients in the U.S. was $12.7 billion, with hospitalizations accounting for 63 percent of the total.38 However, in a 2008 study, researchers indicate that Medicare alone pays $15.7 billion annually to treat newly diagnosed AFib patients.39

78.40%

56.39% 61.37% 69.42%

14.47%

18.39%23.90%

21.62%

2.73%

17.16%6.34%

2.76%1.04%

2.71% 3.81%1.40%

2.36%6.03% 4.59%

4.81%

0%

20%

40%

60%

80%

100%

Hospital Inpatient Hospital Outpatient Emergency Department

Physician's Office

Medicare Private Medicaid Self-Pay Misc/Other

These costs are largely driven by the greater utilization of healthcare services associated with AFib complications such as stroke, HF, acute myocardial infarction, and tachycardia. Importantly, these costs are considered by some to be an underestimate since they exclude deductibles, copayments, medical costs not covered by Medicare,


and patients who have previously been diagnosed with AFib and are currently undergoing treatment.

One study focusing on Medicare patients found that within the first year following an AFib diagnosis, patients with AFib were more likely than a matched cohort of patients without AFib to have HF (36.7 percent versus 10.4 percent) and/or stroke (23.1 percent versus 13.3 percent). This study also found that HF was the second most expensive complication, costing Medicare $12,117 per patient within the first year of diagnosis.40 Another study estimates the annual cost of stroke among Medicare AFib patients is $8 billion.41

Most of the costs associated with AFib and its complications occur in the inpatient hospital setting, largely due to readmissions. In a retrospective cohort study of managed care patients, researchers found that inpatient expenses were about 80 percent of the total costs to treat hospitalized AFib patients.

42 A similar study estimated that 73 percent of total US AFib costs were for inpatient costs.43

Although several studies have examined the costs associated with AFib, these analyses are primarily focused on younger patients in managed care settings. With the exception of a study by Lee and colleagues (2008) which focused on newly diagnosed AFib patients and is based on Medicare data from 2002-2004, there are limited data examining rates of rehospitalization, use of healthcare services in multiple settings of care, and medical costs among Medicare AFib patients.

The purpose of this analysis is to examine rates of health services utilization and medical costs among Medicare AFib patients after an initial hospitalization for AFib based on more recent Medicare data from 2004-2008. This brief is the second in a series in which Avalere examines the burden of AFib on the Medicare program. We present results of an original analysis of AFib patient utilization and medical costs for various healthcare services including hospital inpatient and outpatient services, physician services, and ED services. In the first paper, “Medicare and Atrial Fibrillation: Consequences in Cost and Care” (2009), we described the burden of AFib on the Medicare program, characterized the current state of quality improvement efforts, and proposed potential strategies to improve the quality of care and outcomes for AFib patients.44

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Methodology

Overview Avalere conducted a retrospective database analysis based on Medicare’s five percent Standard Analytic Files (SAFs) for 2004-2008. Specifically, we identified a cohort of Medicare patients with AFib based on the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes,45

We examined patterns of healthcare utilization and associated medical costs among patients in the cohort during the quarter of the index hospitalization and in the four quarters subsequent to the index hospitalization. We refer to these five quarters as the follow-up period (Figure 3).

and constructed an analytic file linking the inpatient, outpatient, and physician claims files for these patients. Our study cohort included patients with a primary diagnosis of AFib during an initial or ‘index’ hospitalization.

Figure 3 Study follow-up period

We assessed the rate and timing of readmissions, the reasons for these readmissions, the average costs of the readmissions; and rates and frequency of, and costs associated with physician and hospital outpatient service utilization. Hospital outpatient visits included services provided in a hospital setting that did not require an overnight stay. Furthermore, we conducted an additional analysis using a larger cohort of patients who had either a primary or secondary diagnosis of AFib during their index hospitalization.

Data source Avalere used the Medicare five percent SAFs to complete this analysis. The five percent SAFs contain ‘final action’ claims data for five percent of the Medicare beneficiary population. The SAFs are constructed from weekly data submissions to the Medicare National Claims History Database, which contains the electronic files of paid Medicare claims.46

Index

Hospitalization

Quarter

Post- Index Hospitalization Quarters

1 2 3 4

There are seven separate SAFs which are specific to various institutional and non-institutional services.


For this analysis we used the SAFs specific to hospital inpatient, hospital outpatient, and physician services for 2004-2008.47

Medicare 5 percent Standard Analytic Files (SAF)

The SAFs contain information related to patient demographics, health services utilization, and Medicare payments. Specifically, they contain diagnosis and procedure codes as well as reimbursement amounts. Notably, we are using the limited data set (LDS) version of the Medicare SAFs which does not include specific dates of medical services. Instead, the files report the quarter of the calendar year when the services are provided.

Database with medical claims for five percent of the Medicare population Includes patient demographics, diagnoses, procedures, and Medicare payments Provides information on services provided in different settings of care and by

different types of providers (i.e., inpatient, hospital outpatient, skilled nursing facility, hospice, home health, physician, and durable medical equipment)

Does not include prescription drug utilization

Study design This is a retrospective, single-arm, cohort study. We constructed a longitudinal database from the Medicare SAFs, linking the claims for inpatient facility, outpatient facility, and physician services provided to patients using encrypted unique patient identifier numbers. Linking these files enabled us to examine the frequency and patterns of healthcare utilization and costs among patients across settings of care and over time.

Key Terms Index hospitalization: the first instance of an admission to an acute care hospital with an AFib diagnosis recorded on the claim. Follow-up period: study observation period, which includes the quarter of and four quarters following the index hospitalization. Readmission: an admission into an acute care hospital after the index hospitalization during the follow-up period.

Study population To identify Medicare beneficiaries with AFib for our study population, we used inpatient SAFs to find the first instance of an admission to a short-term acute

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care hospital with an AFib diagnosis recorded on the claim. We considered this first instance to be a beneficiary’s index hospitalization.

Our study group, or cohort, was comprised of Medicare beneficiaries who had a primary diagnosis of AFib (ICD-9-CM diagnosis code 427.31) at their index hospitalization.48

Figure 4 Study window: continuous enrollment criterion

We required that patients have at least nine consecutive quarters of Medicare enrollment. Specifically, we required beneficiaries to be continuously enrolled in Medicare for the year prior to the quarter of the index hospitalization (four quarters preceding the quarter of the index hospitalization) and the year following the index hospitalization (four quarters following the quarter of the index hospitalization) (Figure 4).

Additional patient analysis Given that AFib is commonly reported as a comorbid condition instead of a primary diagnosis, we performed an additional analysis on an expanded cohort of AFib patients. Specifically, this expanded cohort included those patients who had either a primary or secondary diagnosis of AFib during their index hospitalization (i.e., AFib diagnosis reported in any of the nine diagnosis positions on the medical claim). We analyzed readmissions, use of healthcare services and medical costs for this ‘primary/secondary’ cohort of patients to gauge the impact of AFib as a comorbid condition.

Study Patient Groups ‘Primary’ AFib patient cohort: patients with a primary AFib diagnosis at their initial hospitalization. ‘Primary/secondary’ AFib patient cohort: patients who had a primary or secondary AFib diagnosis at their initial hospitalization.

Four Pre- Index Hospitalization Quarters Four Post- Index Hospitalization Quarters Index

Hospitalization

Quarter


Study outcome measures

Study Outcome Measures Frequency and costs associated with hospital outpatient utilization Frequency and costs associated with physician services Utilization of ER services Rate of readmissions Timing and costs associated with readmissions

Index Hospitalization As previously stated, the index hospitalization is the first hospitalization with an AFib diagnosis.49 We calculated the average length of stay (LOS) and average costs associated with the index hospitalization. We used Medicare payments as reported on the claim file as a proxy for costs. To further characterize the AFib patients included in our cohorts, we examined rates of comorbid conditions using ICD-9-CM diagnosis codes reported on the index hospitalization claim.50 We also examined diagnosis-related group (DRG) and Medicare severity-diagnosis related group (MS-DRG) assignments of the index hospitalization. CMS uses the DRG and MS-DRG systems to classify inpatient hospital stays for each Medicare beneficiary based on their diagnosis and the procedures they received. CMS assigns a numeric weight to each DRG or MS-DRG, indicating how costly that DRG is relative to the average inpatient stay. The weights are used to inform the Medicare payments rendered for each patient’s stay.51 The DRG system informs the assignments through September 2007, while the MS-DRG system informs them starting in October 2007.52

Hospital outpatient, emergency department, and physician utilization and costs

About 93 percent of the patients in our population had an index hospitalization under the DRG system, while the remaining patients’ index hospitalizations occurred after the introduction of the MS-DRG system.

Physician utilization is any separately billable service provided by a physician in various settings of care during the follow-up period. We tracked physician encounters in the physician office setting as well as in the hospital inpatient and outpatient settings, ED, independent laboratory, skilled nursing facility, ambulatory surgical center, and ambulance setting. Hospital outpatient utilization involves services provided in a hospital that do not require an overnight stay. We examined the following utilization parameters for physician utilization, outpatient department, and emergency department visits:

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percent of beneficiaries with at least one physician encounter, hospital outpatient visit or emergency department visit,

mean number of physician encounters, hospital outpatient visits, and emergency department visits, and

timing of the physician encounters, hospital outpatient visits, and emergency department visits relative to the index hospitalization.

We assessed economic outcomes as well. Specifically, we calculated the average cost per physician encounter and hospital outpatient visit, average cost per beneficiary for physician encounters and hospital outpatient visits, and average cumulative cost per beneficiary among those with at least one physician encounter or hospital outpatient visit. The SAFs do not detail the payments associated with emergency room visits. Because we examined data over multiple years, costs were standardized to 2009 values using the medical care component of the Consumer Price Index, a measure of inflation calculated by the United States Bureau of Labor Statistics. We report average costs throughout this paper. Additional cost measures (i.e., medians and standard deviations) appear in Appendix E.

Medical Costs In this study, Medicare payments are a proxy for medical costs. All costs are reported in 2009 US dollars.

Hospital readmissions and costs We defined a hospital readmission as any admission to a short-term acute care hospital during the five quarter follow-up period starting with the index hospitalization quarter. We examined the following readmission outcomes: percentage of beneficiaries with at least one readmission, average length of stay, and average number of readmissions per beneficiary in the patient population.53

In addition, we reported medical costs associated with the hospital readmissions in the follow-up period. We reported on the following costs: cost per readmission, cumulative readmission cost per beneficiary in the patient population, and readmission cost per beneficiary with at least one readmission.

We also calculated the average number of readmissions among those with at least one readmission.


We also tracked the timing of the readmissions relative to the index hospitalization. Specifically, we created a distribution of the readmissions occurring in the same quarter as the index hospitalization, in the quarter following the index hospitalization, and those in subsequent quarters. As with the index hospitalizations, we examined the reasons for readmissions using ICD-9-CM diagnosis codes, DRG assignments, and MS-DRG assignments.

Cardiovascular- and non cardiovascular-related readmissions and costs To better understand the patterns of health services utilization and costs among patients in our study, we differentiated between cardiovascular- and non cardiovascular-related services. Specifically, we defined cardiovascular-related readmissions as those in which the patient was assigned to certain cardiac- related medical and surgical DRGs or MS-DRGs. For example, we included medical DRGs 134 (hypertension), 143 (chest pain), and 127 (heart failure and shock) in our group of cardiovascular-related DRGs. See Appendices A and B for a full list of the DRGs and MS-DRGs used to classify cardiovascular-related admissions. Non cardiovascular-related readmissions are those that were not assigned to the cardiac-related DRGs and MS-DRGs.

In addition, we differentiated between cardiovascular and non cardiovascular outpatient visits and physician encounters. Cardiovascular-related outpatient visits and physician encounters are those with one of several cardiovascular ICD-9-CM diagnosis codes in the primary position. Some examples of cardiovascular-related ICD-9-CM’s are acute myocardial infarction (410.XX), chronic pulmonary heart disease (416.XX), and cardiomyopathy (425.XX). For our full list of cardio-vascular-related diagnosis codes, see Appendix C.

Key Terms Cardiovascular-related readmission: readmissions in which patients were assigned to cardiac related medical and surgical diagnosis related groups Non cardiovascular-related readmission: readmissions in which patients were assigned to diagnosis related groups that were not related to cardiac conditions

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Results

AFib patients in our study had multiple comorbid conditions There were 14,174 patients that 1) had a primary diagnosis of AFib at the time of their index hospitalization and 2) met our criterion of nine quarters of continuous Medicare enrollment. The average age of these AFib patients at the time of their index hospitalization was 76. Sixty percent of them were female. Table 1 provides characteristics of our study cohort including age, gender, race and geographic region.

Table 1 AFib Study Cohort

Characteristic

AFib Cohort (n= 14,174)

Average Age 76.18

Age Group (%)

65-74 35.42 75 58.92 Female (%) 59.50

Race/Ethnicity (%)

White 91.91 Black 5.20 Hispanic 1.17 Asian 0.73 Other 0.62 North American Native 0.27

Census Region (%)

South 39.88 Midwest 26.25 Northeast 21.51 West 12.04 Unknown 0.32

Not surprisingly, AFib patients included in our study were most commonly hospitalized for cardiac arrhythmia (Table 2). In fact, 84 percent of patients were assigned to DRG codes 138 and 139, which are for cardiac arrhythmia with and without complications, respectively.


Table 2 Top five DRGs for AFib patient index hospitalizations

DRG code Description

Percent of total

138 Cardiac Arrhythmia & Conduction Disorders W CC 57.50%

139 Cardiac Arrhythmia & Conduction Disorders W/O CC 26.49%

552 Other Permanent Cardiac Pacemaker Implant W/O Major Cv Dx 2.67%

125 Circulatory Disorders Except AMI, W Card Cath W/O Complex Diag

2.38%

124 Circulatory Disorders Except AMI, W Card Cath & Complex Diag 2.09%

See Appendix D for the results of the MS-DRG index hospitalization assignments.

Patients included in this analysis had several comorbid conditions in addition to AFib which were typically related to hypertension, cardiovascular conditions, and diabetes. Table 3 identifies the top ten comorbidities of AFib patients’ index hospitalizations.

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Table 3 Ten most commonly reported comorbid conditions at index hospitalizations

ICD-9-CM Diagnosis Code Comorbidity Description

Percent of Index Hospitalizations

401 Essential Hypertension 58.46%

272 Disorders of Lipoid Metabolism1 35.35%

414 Other Forms of Chronic Ischemic Heart Disease2 28.67%

427 Cardiac Dysrhythmias 22.86%

428 Heart Failure 22.02%

250 Diabetes Mellitus 18.79%

V45 Other Postsurgical States3 16.15%

424 Other Diseases of Endocardium4 15.83%

276 Disorders of Fluid, Electrolyte, and Acid-Base Balance5

14.47%

244 Acquired Hypothyroidism 13.85% 1 Common disorders of lipoid metabolism include hyperlipidemia and hypercholesterolemia, which relate to high cholesterol. 2 Conditions common to ischemic heart disease are coronary atherosclerosis, dissection, and aneurysm, which are associated with heart attacks. 3 The other post surgical states diagnosis code includes such conditions as post operative dialysis and post operative pacemaker. 4 Diseases of endocardium include conditions related to disorders of the heart valves and inflammation of the heart chamber. 5 Disorders of fluid electrolyte and acid base balance include hyperkalemia, hypocalcemia, acidosis, hyponatremia which relate to acute renal failure of the kidneys.

These results are similar to other published studies of AFib patients, which also indicate high rates of cardiovascular-related comorbid conditions.54,55

AFib patients stayed in the hospital for four days on average during their index hospitalization with an average cost of $5,475 (Table 4). The year in which the index hospitalizations occurred was relatively evenly distributed from 2005 to 2007.


Table 4 Index hospitalization characteristics

Characteristic

AFib Cohort (n= 14,174)

Average Length of Stay (number of days) 3.68 days

Average Cost of Index Hospitalization $5,475

Year of Index Hospitalization (%)

2005 35.80

2006 33.00

2007 31.21

Study Results AFib patients in our study had multiple comorbid conditions Overall average medical costs among AFib patients in this study were nearly $24,000

per patient during the follow-up period AFib patients in our sample had high hospital outpatient and physician services

utilization Many AFib patients visited the emergency department in the follow-up period AFib patients in our study were often readmitted multiple times and shortly after an

initial hospitalization Cardiovascular-related conditions were key causes of hospital readmissions among

AFib patients in our study AFib is often reported as a comorbid condition that may influence healthcare

utilization and costs

Overall average medical costs among AFib patients in this study were nearly $24,000 per patient during the follow-up period The total medical costs of treating AFib patients over the study period averaged almost $24,000 per beneficiary. Figure 5 reports the sum of the average costs per beneficiary in each setting of care including inpatient, outpatient, and physician services. Sixty-two percent ($14,887) of these costs were for inpatient services. Furthermore, 63 percent of the inpatient services costs ($9,412) were related to readmission costs. See Appendix E for more detailed cost information (i.e., medians, standard deviations).

22 |

Figure 5 Total average medical costs by site of service

AFib patients in our sample had high hospital outpatient and physician services utilization We found that AFib patients utilized high amounts of hospital outpatient, physician, and emergency department services in the follow-up period. Hospital outpatient visits include services provided in a hospital setting that do not require an overnight stay. Most patients in our study (90 percent) visited the outpatient hospital at least once in the follow-up period (Table 5). Furthermore, these patients visited the outpatient hospital an average of 12 times during this period. The cumulative cost per beneficiary with at least one visit averaged $2,972. Twenty-eight percent of hospital outpatient visits were for cardio-vascular-related reasons.

$5,475

$9,412

$2,649

$6,363

$0

$5,000

$10,000

$15,000

$20,000

$25,000

Setting of Care

Mean costs per beneficiary

Inpatient Index Hospitalizations Inpatient ReadmissionsOutpatient Services Physician Services

Total Inpatient Costs per Beneficiary = $14,887

Total Costs Across Settings of Care = $23,899


Table 5 Hospital outpatient utilization and costs

Outcome AFib Cohort

(N=14,174)

Number of beneficiaries with at least one visit 12,632

Percent of beneficiaries with at least one visit 89.12%

Average number of visits per beneficiary 10.74

Average number of visits per beneficiary, among those with at least one visit

12.05

Timing of visits (%)

Visits within the same quarter of the index hospitalization 22.39%

Visits in the quarter following the index hospitalization 22.13%

Visits in subsequent quarters 55.48%

Average cost per visit $247

Average cumulative visit cost for beneficiaries with at least one visit $2,972

We observed even higher utilization levels of physician services, which may occur in various settings, including a physician’s office, the hospital inpatient or outpatient settings, the ED, laboratory, or other sites of service (e.g., skilled nursing facility). Specifically, 98 percent of patients had at least one physician encounter in the follow-up period. These patients saw the physician 67 times on average in the follow-up period. Thirty-one percent of these visits were for cardiovascular-related reasons, i.e., hypertension, ischemic heart disease, or heart failure. Related, across all settings of care, cardiology (20 percent) was the leading physician specialty caring for AFib patients, followed by internal medicine (16 percent).

Forty-six percent of physician encounters (n=30) occurred in the physician office setting. Figure 6 shows the distribution of physician service settings of care used by the AFib patients in our study.

24 |

Figure 6 Physician encounters by site of service during the follow-up period

Note: “Other” includes settings such as ambulance, skilled nursing facility, and ambulatory surgical center.

The cost per physician encounter averaged $96. The cumulative cost per beneficiary among those with at least one physician encounter averaged $6,471. See the following table for a summary of physician services utilization and cost findings:

Table 6 Physician services utilization and costs

Outcome AFib Cohort

(N=14,174)

Number of beneficiaries with at least one encounter 13,937

Percent of beneficiaries with at least one encounter 98.33%

Average number of physician encounters per beneficiary 66.12

Average number of encounters per beneficiary, among those with at least one encounter

67.24

Timing of Encounters (%)

Encounters within the same quarter of the index hospitalization 32.19%

Encounters in the quarter following the index hospitalization 19.53%

Encounters in subsequent quarters 48.29%

Average cost per encounter $96

Average cumulative encounter cost for beneficiaries with at least one encounter

$6,471

46%

24%

7% 6% 9% 7%

0%

20%

40%

60%

Physician Office

Inpatient Hospital

Outpatient Hospital

Emergency Room

Independent Lab

Other


Sixty-one percent of AFib patients visited the emergency department in the follow-up period AFib patients also commonly visited the emergency department. In the follow- up period, 61 percent of patients visited the emergency room at least once. They went three times on average post index hospitalization. Furthermore, 65 percent of readmissions were initiated through an emergency room visit. Twenty-nine percent of ED visits were for cardiovascular-related reasons.

AFib patients in our study were readmitted frequently and early after an initial hospitalization More than half (52 percent) of the 14,174 AFib patients in our primary cohort were readmitted to an inpatient hospital at least once during the follow-up period. Furthermore, 12 percent of patients were readmitted three or more times (Figure 7). AFib was the primary diagnosis in 15 percent of all readmissions.

Figure 7 Number of readmissions during the follow-up period

The patients who were readmitted at least once had two readmissions on average during the follow-up period.

A large percentage of hospital readmissions occurred relatively soon after the index hospitalization. Specifically, we found that: about 25 percent of readmissions occurred within the same quarter as the

index hospitalization; and that Twenty three percent of readmissions occurred in the quarter after the index

hospitalization (Figure 8).

48%

27%

12%6% 6%

0%

20%

40%

60%

0 Readmissions 1 Readmission 2 Readmissions 3 Readmissions 4 or more Readmissions

52% of patients were readmitted at least once

26 |

Figure 8 Forty-eight percent of readmissions occurred soon after the index hospitalization

Compared to a younger patient population in a managed care setting, these readmission rates are higher. As previously stated, Kim and colleagues (2009) found hospital readmission rates of about 10 to 12 percent during the one-year following the index hospitalization for a cohort of AFib patients using a national managed care claims database. Similar to our study, this analysis showed that 20 percent of the readmissions occurred within the first month following the index hospitalization and two-thirds of the readmissions occurred within the first six months following the index hospitalization.56

Once readmitted, AFib patients stayed in the hospital for about five days on average, costing Medicare $9,061 on average for each stay (Table 7). Further, the cumulative readmission cost per beneficiary with at least one readmission during the follow-up period averaged $18,192.

Table 7 Hospital readmissions and costs

Outcome AFib Cohort

(N=14,174)

Number of beneficiaries with at least one readmission 7,333

Percent of beneficiaries with at least one readmission 51.74%

Average number of readmissions per beneficiary 1.04

Average number of readmissions per beneficiary, among those with at least one readmission

2.01

Average length of readmission (number of days) 4.79

Average cost per readmission $9,061

Average cumulative readmission cost for beneficiaries with at least one readmission $18,192

25%

Index

Hospitalization

Quarter

Post-Index Hospitalization Quarters

1 2 3 4

23% 52%


Cardiovascular-related conditions were key causes of hospital readmissions among AFib patients in our study Based on an assessment of the DRGs reported at the readmissions, the causes for these readmissions included cardiac- and non cardiac-related reasons. However, the most common DRGs were often related to cardiac conditions (Table 8).

Table 8 DRG assignments for AFib patient readmissions

DRG code DRG description

Percent of total


127 Heart Failure & Shock 9.81%

139 Cardiac Arrhythmia & Conduction Disorders W/O CC 4.53%

089 Simple Pneumonia & Pleurisy Age >17 W CC 3.27%

552 Other Permanent Cardiac Pacemaker Implant W/O Major CV DX

2.60%

Further examination of the ICD-9-CM diagnosis codes for the cardiac-related readmissions showed that 31 percent of readmission claims listed AFib (ICD-9-CM 427.31) in the primary position. Other common primary diagnoses reported for cardiovascular-related readmissions included coronary heart failure (17 percent) and coronary atherosclerosis native vessel (seven percent).

When we did further analysis of all of the DRGs reported for the hospital readmissions and examined those specifically related to cardiovascular conditions (Appendix A), we found 48 percent of readmissions were related to cardiovascular conditions.

28 |

Figure 9 Proportions of readmissions related to cardiovascular and non cardiovascular conditions

AFib patients with cardiovascular-related readmissions stayed in the hospital for about four days on average, costing Medicare an average of $9,477 per stay. Among beneficiaries who had at least one readmission, the average cost per beneficiary of cardiovascular-related readmissions was $15,019, while the average cost per beneficiary of non cardiovascular-related readmissions was $14,178.

Notably, the most common non cardiovascular-related readmissions involved conditions such as pneumonia, chronic obstructive pulmonary disease, and stroke (intracranial hemorrhage or cerebral infarction) (Table 9).

Table 9 Most common non cardiovascular-related conditions

DRG code DRG description

Percent of total

089 Simple Pneumonia & Pleurisy Age >17 W CC 6.36%

182 Esophagitis, Gastroent & Misc Digest Disorders Age >17 W CC

4.75%

174 G.I. Hemorrhage W CC 4.53%

088 Chronic Obstructive Pulmonary Disease 4.28%

014 Intracranial Hemorrhage or Cerebral Infarction 4.00%

In our analysis of the ICD-9-CM diagnosis codes associated with the non cardiovascular-related readmissions, we found that the primary diagnoses codes were more dispersed compared to those of the cardiovascular-related readmissions. The three most common ICD-9-CMs for non cardiovascular-

48%52%

Cardiovascular readmissions

Non-cardiovascular readmissions


related readmissions included pneumonia (six percent), urinary tract infection (three percent) and cerebral artery occlusion not otherwise specified with infarction (three percent).

AFib is often reported as a comorbid condition that may influence healthcare utilization and costs The iteration of the analysis using the primary/secondary cohort yielded similar outcomes. As stated previously, the primary/secondary cohort included AFib patients with a primary or secondary diagnosis of AFib at the index hospitalization. Using this approach, our cohort expanded to 89,799 patients. This considerable increase in our patient sample size indicates that AFib is more often reported as a comorbidity to other conditions than as a primary diagnosis. We describe some of the findings of the primary/secondary iteration below.

Index Hospitalization Consistent with the primary cohort, we observed cardiovascular- and hypertension-related comorbidities in the primary/secondary cohort’s index hospitalizations. In fact, nine of the top 10 conditions of the primary cohort are included in the 10 most common comorbidities of the primary/secondary cohort. However, the average costs associated with index AFib hospitalizations were higher for the primary/secondary cohort relative to the primary cohort. We found that the average cost of treating patients in the primary/secondary cohort was $11,222, compared with the primary cohort where index hospitalizations cost $5,475 on average.

Hospital Readmissions Readmissions of patients in the primary/secondary cohort occurred similarly to those in the primary cohort. Fifty-five percent (n=49,006) of patients had at least one hospital readmission during the follow-up period. We found that 26 percent of readmissions were in the same quarter and 22 percent were in the quarter after the index hospitalization. These primary/secondary patients also stayed in the hospital for five days on average, once readmitted.

Each inpatient hospital readmission cost Medicare about $9,458 on average for primary/secondary patients, which is similar to the average costs for primary patients ($9,061). Furthermore, the cumulative readmission cost per beneficiary with at least one readmission averaged $20,028 for those in the primary/secondary cohort.

30 |

Other Health Services Consistent with the primary cohort, the primary/secondary cohort of AFib patients are frequent users of outpatient and physician health services. About 90 percent of patients visited the outpatient hospital in the follow-up

period. Furthermore, these patients visited the outpatient hospital 12 times on average during the follow-up period.

The average cost per outpatient visit was $290. The average cumulative cost among those with at least one visit was $3,598 per person.

Like the primary patients, 98 percent of patients in the primary/secondary cohort had a physician encounter in the follow-up period. These patients had an average of 75 physician encounters in the follow-up period.

The cost per physician encounter averaged $106. The average cumulative cost for beneficiaries with at least one physician encounter was $7,931.

Overall, costs associated with all settings of care for the primary/secondary cohort averaged $33,200, while the overall costs we found for patients with primary AFib diagnoses were $23,899. This suggests that AFib as a comorbid condition may exacerbate primary conditions, influencing the utilization patterns and costs of care for those conditions. Further research to fully understand the clinical and economic impact of AFib as a comorbid condition would be valuable.

Limitations

This study had several noteworthy limitations. First, administrative claims data, such as the Medicare SAFs, are not collected for research purposes and as such, only minimal clinical information can be derived from these databases with certainty. In the absence of clinical data, it is difficult to assess the severity of disease in patients and actual reasons for hospitalizations. In this study, similar to other studies based on medical claims databases, we used ICD-9-CM diagnosis codes and DRG assignments to make inferences about reasons for hospitalizations.

Second, as previously mentioned, the Medicare SAFs include quarter of service rather than exact dates of service. As reported in this paper, 24 percent of patients had more than one hospitalization in the same quarter as the index hospitalization. We used various methods to differentiate between the index hospitalization and other hospitalizations occurring in the same quarter. These


methods included taking advantage of the inherent chronological ordering in a portion of the claims, and using the presence of a patient co-payment or deductible as an indicator of the first or multiple admissions in a quarter. Despite these efforts, it is possible that we did not accurately differentiate between index hospitalizations and readmissions for all patients.

Third, the Medicare SAFs do not contain prescription drug utilization or costs. In addition, costs that are not covered by Medicare, such as patient out-of-pocket payments and co-pays for supplemental insurance, are not included in the SAFs, and thus are not included in our analysis. Therefore, the costs reported in this paper likely represent an underestimate of the direct medical costs associated with treating Medicare AFib patients. Some studies have shown that drug costs alone for AFib patients may comprise up to 20 to 23 percent of total costs.57,58

Fourth, in some instances, we may not have accurately captured a patient’s first AFib hospitalization. As the study period was restricted from 2004 to 2008, we were unable to observe AFib hospitalizations that occurred prior to 2004. By examining claims history for nine quarters, we were able to confirm that the index hospitalization was the first hospitalization during that time period.

Fifth, this retrospective evaluation was descriptive and did not include comparisons to patients without AFib. Although one of the goals of this analysis was to gain a better understanding of the costs associated with AFib, without a statistically matched comparison group, we cannot fully attribute the costs reported in this paper to AFib. To further understand AFib-related costs, we defined and examined cardiovascular-related and non cardiovascular-related health services utilization. However, this approach does not allow for a full examination of health services utilization and costs attributable to AFib.

Sixth, by basing our cohort of AFib patients, and several study outcomes, on ICD-9-CM diagnosis codes, our approach is susceptible to coding mistakes or inaccurate coding practices by physicians and other healthcare providers. Furthermore, any potential variation in reporting of ICD-9-CM diagnosis codes affects the ability to define and assess utilization of cardiovascular- and non cardiovascular-related services. To maximize the likelihood that patients in our study cohort actually had AFib, we required that a diagnosis of AFib be reported as the primary diagnosis for the index hospitalization.

32 |

Seventh, because our study examined health services utilization from 2004 through 2008, some patients’ index hospitalization occurred prior to the implementation of the new MS-DRG Medicare payment system in October of 2007, while others’ occurred after this change. Only seven percent (n=992) of patients had an index hospitalization after the introduction of the MS-DRG system. However, 31 percent of patients whose index hospitalizations occurred prior to October 2007 had follow-up periods that spanned both the old DRG system and the new MS-DRG system. To gauge whether there might have been bias introduced into our analysis by including inpatient services coded and reported under both the DRG and MS-DRG systems, we examined the volume of AFib hospitalizations during the entire timeframe of our study (2004 through 2008). Specifically we assessed the volume of AFib hospitalizations as a percent of total hospital discharges where AFib was reported as either the primary or secondary diagnosis. Our analysis showed a decrease in the relative volume of hospitalizations with a reported diagnosis of AFib starting in the fourth quarter of 2007. Specifically, AFib hospitalizations were 17 percent of all hospitalizations in 2004, 17 to 18 percent in 2005, 18 to 19 percent in 2006, and 19 percent of hospitalizations in the first three quarters of 2007. Starting in the fourth quarter of 2007, AFib hospitalizations decreased to 16 percent and remained at 15 to 16 percent through 2008. Without additional information, it is not possible to determine the significance of, or reason for this sustained decline in the volume of AFib hospitalizations. However, it indicates the potential for under- or over-reporting of AFib hospitalizations in our study, which means that we may not be accurately characterizing the index hospitalizations or hospital readmissions for certain patients in our analysis. This interesting finding may warrant further exploration.

Finally, this study cannot be generalized to all patients with AFib, especially to those who may not have ever been hospitalized for AFib, or who are younger. AFib patients who are admitted to the hospital are likely sicker than those who have never been admitted. These patients will use more healthcare services and have higher associated costs. By defining our patient population on the presence of a primary AFib hospitalization, our study inherently reflects the most resource intensive AFib patients. Furthermore, by restricting our study to Medicare, we are including the oldest AFib patients, who are more likely to be sicker than AFib patients under age 65. Thus, the findings of this study should not be applied to the entire AFib patient population.


Conclusions

This retrospective study assessed health resource utilization and associated costs over a five quarter period following an index hospitalization for AFib in a well-defined cohort of Medicare patients. The results provide valuable information on a unique subset of the AFib patient population that has not been well characterized in the literature.

Conclusions Medical costs among patients in our study are high and driven primarily by inpatient

costs Patients in our analysis have high rates of outpatient, physician services, and ED

utilization AFib patients in our study have relatively high rates of readmissions soon after initial

AFib hospitalization AFib is often reported as a comorbid condition and may influence healthcare

utilization and costs Additional research required to understand frequency and timing of readmissions,

and impact of AFib as comorbid condition

AFib medical costs in our study are high and driven primarily by inpatient costs Average medical costs among AFib patients included in this analysis were $23,899 over the five quarters following the index hospitalization. This result is consistent with one published study that was also based on Medicare AFib patients, but is higher than a few other published reports of AFib patients that were focused on patient populations which were not comparable to our study group. In our analysis, the majority of medical costs (62 percent) during the follow-up period were comprised of inpatient hospital costs. Furthermore, most of the inpatient hospital costs (63 percent) were associated with readmissions. To the extent that some of these readmissions could be avoided by improved care management, there may be opportunities for providers and payers to reduce these overall medical costs. For example, AFib may be an ideal target for quality improvement efforts. In light of current health reform discussions on reducing costs, and improving care quality, federal policymakers may consider prioritizing AFib among the chronic conditions targeted for Medicare’s quality improvement efforts.

34 |

These average costs per patient are higher than those in the relatively recent study on the cost of AFib to U.S. managed care organizations by Kim and colleagues. The authors found that average total inpatient costs were $11,307 per patient while we found them to be higher at $14,887. This difference is likely attributable in part to the fact that we include five quarters of data (quarter of the index hospitalization and four quarters after) in our study period whereas they only used four quarters of data. Further, in contrast to our results, Kim observed that most of the inpatient services costs were associated with the initial hospitalization costs (75 percent) while the remainder were related to hospital readmissions.59

Other AFib studies have reported lower annual medical costs than those reported in this analysis.

This difference may be attributable to our study population being older and having more comorbidities. Kim included AFib patients who were at least 20 years of age and older, while we restricted our study population to Medicare beneficiaries only.

60,61

The costs observed in our study are comparable to those reported by Lee and colleagues.

However, these studies analyzed different types of patients than those included in our analysis. Our analysis included only Medicare beneficiaries and patients who have had at least one hospitalization for AFib. Therefore, they represent an older, sicker patient population compared to existing published reports that have focused on younger managed care patients or patients who have been newly diagnosed with AFib.

62

In addition, the total AFib costs per patient for five quarters reported in our analysis are similar to those reported in studies of other costly cardiovascular conditions. For example:

Using the five percent Medicare SAFs, Lee reported average one-year healthcare costs in a cohort of AFib patients to be $23,750, compared to our finding of $23,899 over five quarters. Inpatient costs account for the majority (57 percent) of the costs during the one-year follow-up period. However, interestingly, this study focused on newly diagnosed AFib patients, whereas we examined patients after an initial hospitalization for AFib, who were likely a sicker patient population. Further, Lee and colleagues included medical costs from the skilled nursing facilities, home healthcare, durable medical equipment, and hospice in their analysis. Although we included physician costs from skilled nursing facilities, we did not include facility costs from this setting of care.

According to two studies based on managed care data, average one-year medical costs for patients with acute coronary syndrome, including


myocardial infarction and unstable angina, ranged from $22,500 to $41,000.63,64

A recent study analyzing costs and health resource utilization for Medicare patients with heart failure and diabetes reported aggregated two-year mean costs of $32,676 for patients with diabetes and heart failure and $22,230 for patients with heart failure only.

65

Patients in our analysis have high rates of health services utilization

Consistent with previous studies, health services utilization in the outpatient setting, including physician encounters and hospital outpatient visits, were high in our patient study population and contributed to the medical costs observed among these patients. On average, patients had 67 physician encounters during the follow-up period, 30 of which occurred in the physician office setting.

Hospital outpatient use was also frequent among patients in our study — 89 percent of them had at least one hospital outpatient visit. These patients visited the hospital outpatient department 12 times on average during the follow-up period. Finally, 61 percent of patients visited the emergency room at least once during the follow-up period.

AFib patients in our study have relatively high rates of readmissions soon after initial AFib hospitalization In our analysis, 52 percent of patients were readmitted during the five quarters following an initial hospitalization for AFib, and 12 percent of patients had three or more hospitalizations. Nearly half of the hospital readmissions occurred in the same quarter as the index hospitalization or the quarter immediately following the index hospitalization. In addition, nearly half of the readmissions were for cardiovascular-related conditions, and 65 percent of the readmissions were initiated through a visit to the ED.

Given these findings and those in other studies showing high readmission rates in the period shortly following an initial AFib hospitalization,66

further research may be necessary to better understand the causes driving this interesting finding, especially considering the substantial costs associated.

36 |

AFib is often reported as a comorbidity and may influence health services utilization and costs When we expanded our patient study sample to include patients who had an index hospitalization with AFib reported as either a primary or secondary diagnosis, our sample increased six-fold from 14,174 to 89,799, suggesting that AFib is reported more often as a comorbid diagnosis than a primary diagnosis. Average medical costs during the follow-up period were also higher among patients ($33,200) with AFib reported as either a primary or secondary diagnosis at the index hospitalization compared to patients with AFib reported as a primary diagnosis ($23,899). These results suggest that the presence of AFib as a comorbid condition may influence use of healthcare services and medical costs. Further research should consider exploring the specific clinical and economic impact of AFib as a comorbid condition.

In summary, this study provides valuable information on the utilization of healthcare resources and medical costs among a well-defined cohort of Medicare AFib patients following an initial hospitalization for AFib. The findings highlight the economic burden of AFib among older AFib Medicare beneficiaries and emphasize the need for improved management strategies to help reduce the high health services utilization and medical costs in all settings of care for Medicare AFib patients. As the Medicare population continues to grow and the prevalence of AFib increases, reforms aimed at additional research, quality improvement, and cost management will be critical to support the advancement of AFib treatment, improve patient outcomes, and reduce costs for the Medicare program.


Appendix A

Cardiovascular-Related Diagnosis Related Group (DRG) Codes*

DRG Code Description

104 Cardiac Valve & Oth Major Cardiothoracic Proc W Card Cath

105 Cardiac Valve & Oth Major Cardiothoracic Proc W/O Card Cath

106 Coronary Bypass W PTCA

108 Other Cardiothoracic Procedures

110 Major Cardiovascular Procedures W CC

111 Major Cardiovascular Procedures W/O CC

113 Amputation for Circ System Disorders Except Upper Limb & Toe

114 Upper Limb & Toe Amputation FFR Circ System Disorders

117 Cardiac Pacemaker Revision Except Device Replacement

118 Cardiac Pacemaker Device Replacement

119 Vein Ligation & Stripping

120 Other Circulatory System O.R. Procedures

121 Circulatory Disorders W AMI & Major Comp, Discharged Alive

122 Circulatory Disorders W AMI W/O Major Comp, Discharged Alive

123 Circulatory Disorders W AMI, Expired

124 Circulatory Disorders Except AMI, W Card Cath & Complex Diag

125 Circulatory Disorders Except AMI, W Card Cath W/O Complex Diag

126 Acute & Subacute Endocarditis

127 Heart Failure & Shock

128 Deep Vein Thrombophlebitis

129 Cardiac Arrest, Unexplained

130 Peripheral Vascular Disorders W CC

131 Peripheral Vascular Disorders W/O CC

132 Atherosclerosis W CC

133 Atherosclerosis W/O CC

134 Hypertension

38 |

DRG Code Description

135 Cardiac Congenital & Valvular Disorders Age >17 W CC

136 Cardiac Congenital & Valvular Disorders Age >17 W/O CC

137 Cardiac Congenital & Valvular Disorders Age 0-17

138 Cardiac Arrhythmia & Conduction Disorders W CC

139 Cardiac Arrhythmia & Conduction Disorders W/O CC

140 Angina Pectoris

141 Syncope & Collapse W CC

142 Syncope & Collapse W/O CC

143 Chest Pain

144 Other Circulatory System Diagnoses W CC

145 Other Circulatory System Diagnoses W/O CC

479 Other Vascular Procedures W/O CC

515 Cardiac Defibrillator Implant W/O Cardiac Cath

518 Perc Cardio Proc W/O Coronary Artery Stent Or AMI

525 Other Heart Assist System Implant

535 Cardiac Defib Implant W Cardiac Cath W AMI/HF/Shock

536 Cardiac Defib Implant W Cardiac Cath W/O AMI/HF/Shock

547 Coronary Bypass W Cardiac Cath W Major CV DX

548 Coronary Bypass W Cardiac Cath W/O Major CV DX

549 Coronary Bypass W/O Cardiac Cath W Major CV DX

550 Coronary Bypass W/O Cardiac Cath W/O Major CV DX

551 Permanent Cardiac Pacemaker Impl W Maj CV DX Or AICD Lead Or GNRTR

552 Other Permanent Cardiac Pacemaker Implant W/O Major CV DX

553 Other Vascular Procedures W CC W Major CV DX

554 Other Vascular Procedures W CC W/O Major Cv Dx

555 Percutaneous Cardiovascular Proc W Major CV DX

556 Percutaneous Cardiovasc Proc W Non-Drug-Eluting Stent W/O Maj CV DX

557 Percutaneous Cardiovascular Proc W Drug-Eluting Stent W Major CV DX

558 Percutaneous Cardiovascular Proc W Drug-Eluting Stent W/O Maj CV DX

*CC=complicating condition; DX=Diagnosis


Appendix B

Cardiovascular-Related Medicare Severity–Diagnosis Related Group (MS-DRG) Codes*

MS-DRG Code Description

215 Other heart assist system implant

216 Cardiac valve & oth maj cardiothoracic proc w card cath w MCC

217 Cardiac valve & oth maj cardiothoracic proc w card cath w CC

218 Cardiac valve & oth maj cardiothoracic proc w card cath w/o CC/MCC

219 Cardiac valve & oth maj cardiothoracic proc w/o card cath w MCC

220 Cardiac valve & oth maj cardiothoracic proc w/o card cath w CC

221 Cardiac valve & oth maj cardiothoracic proc w/o card cath w/o CC/MCC

222 Cardiac defib implant w cardiac cath w AMI/HF/shock w MCC

223 Cardiac defib implant w cardiac cath w AMI/HF/shock w/o MCC

224 Cardiac defib implant w cardiac cath w/o AMI/HF/shock w MCC

225 Cardiac defib implant w cardiac cath w/o AMI/HF/shock w/o MCC

226 Cardiac defibrillator implant w/o cardiac cath w MCC

227 Cardiac defibrillator implant w/o cardiac cath w/o MCC

228 Other cardiothoracic procedures w MCC

229 Other cardiothoracic procedures w CC

230 Other cardiothoracic procedures w/o CC/MCC

231 Coronary bypass w PTCA w MCC

232 Coronary bypass w PTCA w/o MCC

233 Coronary bypass w cardiac cath w MCC

234 Coronary bypass w cardiac cath w/o MCC

235 Coronary bypass w/o cardiac cath w MCC

236 Coronary bypass w/o cardiac cath w/o MCC

237 Major cardiovasc procedures w MCC or thoracic aortic aneurysm repair

238 Major cardiovasc procedures w/o MCC

239 Amputation for circ sys disorders exc upper limb & toe w MCC

40 |


240 Amputation for circ sys disorders exc upper limb & toe w CC

241 Amputation for circ sys disorders exc upper limb & toe w/o CC/MCC

242 Permanent cardiac pacemaker implant w MCC

243 Permanent cardiac pacemaker implant w CC

244 Permanent cardiac pacemaker implant w/o CC/MCC

245 AICD lead & generator procedures

246 Perc cardiovasc proc w drug-eluting stent w MCC or 4+ vessels/stents

247 Perc cardiovasc proc w drug-eluting stent w/o MCC

248 Perc cardiovasc proc w non-drug-eluting stent w MCC or 4+ ves/stents

249 Perc cardiovasc proc w non-drug-eluting stent w/o MCC

250 Perc cardiovasc proc w/o coronary artery stent or AMI w MCC

251 Perc cardiovasc proc w/o coronary artery stent or AMI w/o MCC

252 Other vascular procedures w MCC

253 Other vascular procedures w CC

254 Other vascular procedures w/o CC/MCC

255 Upper limb & toe amputation for circ system disorders w MCC

256 Upper limb & toe amputation for circ system disorders w CC

257 Upper limb & toe amputation for circ system disorders w/o CC/MCC

258 Cardiac pacemaker device replacement w MCC

259 Cardiac pacemaker device replacement w/o MCC

260 Cardiac pacemaker revision except device replacement w MCC

261 Cardiac pacemaker revision except device replacement w CC

262 Cardiac pacemaker revision except device replacement w/o CC/MCC

263 Vein ligation & stripping

264 Other circulatory system O.R. procedures

280 Acute myocardial infarction, discharged alive w MCC

281 Acute myocardial infarction, discharged alive w CC

282 Acute myocardial infarction, discharged alive w/o CC/MCC

283 Acute myocardial infarction, expired w MCC

284 Acute myocardial infarction, expired w CC

285 Acute myocardial infarction, expired w/o CC/MCC



286 Circulatory disorders except AMI, w card cath w MCC

287 Circulatory disorders except AMI, w card cath w/o MCC

288 Acute & subacute endocarditis w MCC

289 Acute & subacute endocarditis w CC

290 Acute & subacute endocarditis w/o CC/MCC

291 Heart failure & shock w MCC

292 Heart failure & shock w CC

293 Heart failure & shock w/o CC/MCC

294 Deep vein thrombophlebitis w CC/MCC

295 Deep vein thrombophlebitis w/o CC/MCC

296 Cardiac arrest, unexplained w MCC

297 Cardiac arrest, unexplained w CC

298 Cardiac arrest, unexplained w/o CC/MCC

299 Peripheral vascular disorders w MCC

300 Peripheral vascular disorders w CC

301 Peripheral vascular disorders w/o CC/MCC

302 Atherosclerosis w MCC

303 Atherosclerosis w/o MCC

304 Hypertension w MCC

305 Hypertension w/o MCC

306 Cardiac congenital & valvular disorders w MCC

307 Cardiac congenital & valvular disorders w/o MCC

308 Cardiac arrhythmia & conduction disorders w MCC

309 Cardiac arrhythmia & conduction disorders w CC

310 Cardiac arrhythmia & conduction disorders w/o CC/MCC

311 Angina pectoris

312 Syncope & collapse

313 Chest pain

314 Other circulatory system diagnoses w MCC

315 Other circulatory system diagnoses w CC

316 Other circulatory system diagnoses w/o CC/MCC *CC=complicating condition; MCC=major complicating condition

42 |

Appendix C

Cardiovascular-Related International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) Diagnosis Codes

ICD-9-CM Diagnosis Code Description

093.xx Cardiovascular syphilis

306.2 Physiological malfunction arising from mental factors: Cardiovascular

402.0x Hypertensive heart disease: Malignant

402.1x Hypertensive heart disease: Benign

402.9x Hypertensive heart disease: Unspecified

404.1x Hypertensive heart and chronic kidney disease: Benign

404.9x Hypertensive heart and chronic kidney disease: Unspecified

410.xx Acute myocardial infarction

411.xx Other acute and subacute forms of ischemic heart disease

414.xx Other forms of chronic ischemic heart disease

416.xx Chronic pulmonary heart disease

427.xx Cardiac dysrhythmias

428.xx Heart failure

429.xx Myocarditis, unspecified

746.xx Other congenital anomalies of heart

747.xx Other congenital anomalies of circulatory system

785.0 Tachycardia, unspecified

785.1 Palpitations

785.2 Undiagnosed cardiac murmurs

785.3 Other abnormal heart sounds

785.9 Other symptoms involving cardiovascular system

794.3 Nonspecific abnormal results of function studies: Cardiovascular

794.31 Nonspecific abnormal results of function studies: Abnormal electrocardiogram [ECG] [EKG]

794.39 Nonspecific abnormal results of function studies: Other


972.xx Poisoning by agents primarily affecting the cardiovascular system

V17.41 Family history of sudden cardiac death [SCD]

V17.49 Family history of other cardiovascular diseases

V47.2 Other cardiorespiratory problems

V71.7 Observation for suspected cardiovascular disease

V81.xx Special screening for cardiovascular, respiratory, and genitourinary diseases

44 |

Appendix D

Medicare Severity–Diagnosis Related Group (MS-DRG) Assignments for Index Hospitalization Among index hospitalizations, we found the distribution of MS-DRG assignments to be more dispersed than those of DRG assignments, although cardiac arrhythmia with and without complications are among the most common. The MS-DRGs are not as concentrated as the DRGs, likely due to the method used to convert DRGs into MS-DRGs. Some DRGs were split into three MS-DRGs in the fourth quarter of 2007. See the table below for the top five MS-DRG assignments for AFib patients among their index hospitalizations. About seven percent of the index hospitalizations were under the MS-DRG system.

Table 10 Top 5 MS-DRGs for AFib Patient Index Hospitalizations

MS-DRG code Description

Percent of total

310 Cardiac Arrhythmia & Conduction Disorders W/O CC/MCC 8.43%

292 Heart Failure & Shock W CC 3.41%


291 Heart Failure & Shock W MCC 2.96%

293 Heart Failure & Shock W/O CC/MCC 2.96%


Appendix E

Overall Medical Costs during Follow-up Period by Site of Service

Setting of Care Statistic Primary Cohort Primary/Secondary

Cohort

Inpatient - Index Hospitalization

Mean (St Dev) $5,475 ($6,015) $11,222 ($14,068)

[Median] [$4,079] [$6,513]

Inpatient - Readmissions

Mean (St Dev) $9,412 ($17,768) $10,930 ($21,497)

[Median] [$2,119] [$3,668]

Inpatient - TOTAL Mean (St Dev) $14,887 ($23,783) $22,152 ($35,565)

[Median] [$6,198] [$10,181]

Hospital Outpatient Mean (St Dev) $2,649 ($7,379) $3,244 ($8,310)

[Median] [$901] [$1,082]

Physician Office Mean (St Dev) $6,363 ($7,852) $7,804 ($8,474)

[Median] [$4,736] [$5,876]

TOTAL Mean (St Dev) $23,899 ($39,014) $33,200 ($52,349)

[Median] [$11,835] [$17,139]

46 |

Glossary of Key Terms

Cardiovascular-related readmission: readmissions in which patients were assigned to cardiac-related medical and surgical diagnosis related groups

Diagnosis Related Group (DRG): a reimbursement code that CMS used prior to October 2007 to classify Medicare beneficiary inpatient hospital stays based on the diagnosis and the procedures received; these codes corresponded to a numeric weight which was used to inform the appropriate payment for each beneficiary’s stay

Follow-up period: five quarters of observation including the quarter of the index hospitalization and the four quarters following the index hospitalization quarter

The International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM): the official system of assigning codes to diagnoses and procedures associated with hospital utilization in the United States

Index hospitalization: the first instance of an admission to an acute care hospital with an AFib diagnosis recorded on the claim

Medicare Severity Diagnosis Related Groups (MS-DRG): a code CMS uses to classify Medicare beneficiary inpatient hospital stays based on the diagnosis and the procedures received; these codes correspond to a numeric weight which is used to inform the appropriate payment for each beneficiary’s stay

Non cardiovascular-related readmission: readmissions in which patients were assigned to diagnosis related groups that were not related to cardiac conditions

Primary AFib patient cohort: patients with a primary AFib diagnosis at their initial hospitalization

Primary/secondary AFib patient cohort: patients who had a primary or secondary AFib diagnosis at their initial hospitalization

Hospital readmission: an admission into an acute care hospital after the index hospitalization during the five quarters of the follow-up period

Standard Analytic File (SAF): a publicly available database of final action paid Medicare claims for inpatient, outpatient, skilled nursing facility, hospice, home health, physician, or durable medical equipment services


Endnotes

1 . Lee W Lamas G. Balu S.,et al., “Direct treatment cost of atrial fibrillation in the

elderly American population: a Medicare perspective.” Journal of Medical Economics. (2008): 281-298.

2 . Kim, Michael H., Jay Lin, Mohamed Hussein, Charles Kerilick, and David

Battleman, “Cost of Atrial Fibrillation in United States Managed Care Organizations.” Adv Ther. (2009) 26(9):847-857.

3 . Lee W. Lamas G. Balu S, et al. “Direct treatment cost of atrial fibrillation in the

elderly American population: a Medicare perspective.” Journal of Medical Economics. (2008): 281-298. $15.7 billion is calculated as follows: from a 5 percent Medicare sample size the study identifies patients with AF and non-AF. The difference in cost for these two populations is $14,199 per person more for the AF population compared to non-AF. Since this is a sample size the costs need to be extrapolated to the full population. Therefore, $14,199 multiplied by the sample size of 55,260, multiplied by 20 to reflect 100 percent of the Medicare population.

4 . “Medicare and Atrial Fibrillation: Consequences in Cost and Care.” Avalere

Health, September 2009. 5 . Assistant Secretary for Planning and Evaluation. Data Directory. Centers for

Medicare & Medicaid Services. 5. 2. 2 – 4. http://aspe.hhs.gov/datacncl/DataDir/cms.htm

6 . Niefeld. M. et al., “Preventable Hospitalizations Among Elderly Medicare

Beneficiaries with Type 2 Diabetes.” Diabetes Care. (2003) 26(5): 1344. 7 . Kim, Michael H., Jay Lin, Mohamed Hussein, Charles Kerilick, and David


8 . Reynolds, Matthew, Essebag V, Zimetbaum P, Cohen D. “Healthcare Resource

Utilization and Costs Associated with Recurrent Episodes of Atrial Fibrillation: The FRACTAL Registry.” J Cardiovasc Elecrophysiol. 2007;18:628-633.

http://aspe.hhs.gov/datacncl/DataDir/cms.htm

48 |

9 . Lee W. Lamas G. Balu S., et al. “Direct treatment cost of atrial fibrillation in

the elderly American population: a Medicare perspective.” Journal of Medical Economics. 11 (2008): 281-298.

10. We captured the physician costs associated with the skilled nursing facility in

our analysis as they were included in the carrier SAF. 11. Etemad LR, McCollam PL. “Total First Year Costs of Acute Coronary Syndrome

in a Managed Care Setting.” J Manag Care Pharm. 2005;11(4):300-06. 12 . Menzin J, Wygant G, Hauch O, Jackel J, Friedman M. “One-year costs of

ischemic heart disease among patients with acute coronary syndromes: findings from a multi-employer claims database.” Curr Med Res Opin. 2008 Feb;24(2):461-8.

13. Bogner HR, Miller SD, de Vries HF, Chhatre S, Jayadevappa R. “Assessment of

cost and health resource utilization for elderly patients with heart failure and diabetes mellitus.” J Card Fail. 2010 June;16(6):454-60. Epub 2010 Mar 6.

14. Go A. Hylek E. Phillips K., et al. “Factors in Atrial Fibrillation(ATRIA) Study

Stroke Prevention: The Anticoagulation and Risk National Implications for Rhythm Management and Prevalence of Diagnosed Atrial Fibrillation in Adults.” JAMA, 2001: 285(18):2370-2375.

15. Nattel S. “New ideas about atrial fibrillation 50 years on.” Nature. 415

(2002):219-26. 16. eMedicineHealth. Atrial Fibrillation. 1. 7-10.

http://www.emedicinehealth.com/atrial_fibrillation/page2_em.htm 17. Go A. Hylek E. Phillips K., et al. “Factors in Atrial Fibrillation(ATRIA) Study

Stroke Prevention: The Anticoagulation and Risk National Implications for Rhythm Management and Prevalence of Diagnosed Atrial Fibrillation in Adults.” JAMA, 2001: 285(18):2370-2375.

18. Fuster V, et al. "ACC/AHA/ESC Guidelines for the Management of Patients with

Atrial Fibrillation." Circulation. 2001; 104:2118-2150. 19. American Heart Association. About Arrhythmia. Fibrillation. 2. 1 – 6. accessed

May 21, 2009. http://www.americanheart.org/presenter.jhtml?identifier=34

http://www.emedicinehealth.com/atrial_fibrillation/page2_em.htm


20 . Nattel S. “New ideas about atrial fibrillation 50 years on.” Nature 415

(2002):219-26. 21. Nattel S. “New ideas about atrial fibrillation 50 years on.” Nature 415

(2002):219-26. 22. Fuster, V., et al., ACC/AHA/ESC 2006 guidelines for the management of

patients with atrial fibrillation-executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Revise the 2001 Guidelines for the Management of Patients with Atrial Fibrillation). Eur Heart J, 2006. 27(16): p. 1979-2030.

23. Nattel S. “New ideas about atrial fibrillation 50 years on.” Nature.415:6868;

219-226. January 10, 2002. Go AS, Hylek EM, Phillips KA; et al. and “Factors In Atrial Fibrillation (ATRIA) Study Stroke Prevention: the Anticoagulation and Risk National Implications for Rhythm Management and Prevalence of Diagnosed Atrial Fibrillation in Adults.” JAMA. 2001;285(18):2370-2375. CDC. Atrial Fibrillation Fact Sheet. http://www.cdc.gov/DHDSP/library/pdfs/fs_atrial_fibrillation.pdf [August 26,2008].

24. Heart Rhythm Society. “Atrial Fibrillation Facts.”

http://www.hrsonline.org/News/Media/fact-sheets/Atrial-Fibrillation-Facts.cfm (accessed April 29, 2009).

25. Fuster, V., et al., ACC/AHA/ESC 2006 guidelines for the management of


50 |



27. Nichols, Gregory, et al., “Independent Contribution of Diabetes to Increased

Prevalence and Incidence of Atrial Fibrillation.” Diabetes Care. 32(10), October 2009. 1851-1856. This result is from an observational age and sex matched cohort longitudinal study of 34,744 patients with and without diabetes. After adjusting for several risk factors, diabetes was associated with a 26 percent increased risk of AFib among women, but was not statistically significant among men.





30. Dorian P, Werner J, Newman D, et al. “The impairment of health-related

quality of life patients with intermittent atrial fibrillation: implications for the assessment of investigational therapy.” Journal of the American College of Cardiology. 36 (2000) No. 4.



32. Dorian P, Werner J, Newman D, et al. “The impairment of health-related

quality of life patients with intermittent atrial fibrillation: implications for the assessment of investigational therapy.” Journal of the American College of Cardiology. 36 (2000) No. 4.




34. Wattigney WA, et al., “Increasing trends in hospitalization for atrial

fibrillation in the United States, 1985 through 1999: implications for primary prevention.” Circulation.108 (2003): 711-716.

35. Lee W Lamas G. Balu S.,et al., “Direct treatment cost of atrial fibrillation in the

elderly American population: a Medicare perspective.” Journal of Medical Economics. (2008): 281-298.

36. Kim M. Lin Ju., and Hussein M. “Incidence and Temporal Pattern of Hospital

Readmissions for Patients with Atrial Fibrillation.” Current Medical Research and Opinion. 25 (2009) 5: 1215-1220.

37. Miyasaka Yoko et al., “Changing trends of hospital utilization after their first

episode of atrial fibrillation.” The American Journal of Cardiology. 2008; www.AJConline.org

38. Kim, Michael H., Jay Lin, Mohamed Hussein, Charles Kerilick, and David


39. Lee W. Lamas G. Balu S, et al. “Direct treatment cost of atrial fibrillation in the

elderly American population: a Medicare perspective.” Journal of Medical Economics. (2008): 281-298. $15.7 billion is calculated as follows: from a 5 percent Medicare sample size the study identifies patients with AF and non-AF. The difference in cost for these two populations is $14,199 per person more for the AF population compared to non-AF. Since this is a sample size the costs need to be extrapolated to the full population. Therefore, $14,199 multiplied by the sample size of 55,260, multiplied by 20 to reflect 100 percent of the Medicare population.

40. Lee W Lamas G. Balu S.,et al., “Direct treatment cost of atrial fibrillation in

the elderly American population: a Medicare perspective.” Journal of Medical Economics. (2008): 281-298.

http://www.ajconline.org/

52 |

41. Caro J. “An Economic Model of Stroke in Atrial Fibrillation: The Costs of

Suboptimal Oral Anticoagulation.” The American Journal of Managed Care. 10 (2004) Number14: S451-S461.



43. Coyne K., et al. “Assessing the Direct Costs of Treating Nonvalvular Atrial

Fibrillation in the United States.” Value in Health. 9 (2006) 5:348-356. 44. “Medicare and Atrial Fibrillation: Consequences in Cost and Care.” Avalere

Health, September 2009. 45. Centers for Disease Control and Prevention. International Classification of

Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). 1. 1. 4 – 6. http://www.cdc.gov/nchs/icd/icd9cm.htm

46. Assistant Secretary for Planning and Evaluation. Data Directory. Centers for

Medicare & Medicaid Services. 5. 2. 2 – 4. http://aspe.hhs.gov/datacncl/DataDir/cms.htm

47. 2008 was the latest year that SAFs were available. Although ASPE indicates

that “CMS creates the SAFs six months following the end of the calendar year,” past experience shows that it can take a year to generate the previous year’s SAF.

48. Primary diagnosis codes are indicated on the first position of the claim, while

secondary diagnosis codes are indicated in positions two through nine on the claim.

49. For the primary population, the AFib code had to be in the first position on

the claim while for the primary/secondary population, the code could be in any position on the claim.

50. ICD-9-CM codes were summarized at the three digit level. 51. GAO-06-880. United States Government Accountability Office Report to

Congressional Committees. “Medicare: CMS’s Proposed Approach to Set Hospital Inpatient Payments Appears Promising.” July 2006.

http://aspe.hhs.gov/datacncl/DataDir/cms.htm


52. In the fourth quarter of 2007, CMS changed the DRGs to MS-DRGs to better

reflect disease severity in each of the inpatient hospital stays. Some DRGs were split into three MS-DRGs that specify complications and comorbidities in greater detail.

53. The denominator for the number of readmissions per beneficiary is the

number of patients in each population, so it includes patients that did not have a readmission.



55. Lee W. Lamas G. Balu S., et al. “Direct treatment cost of atrial fibrillation in


56. Kim M. , Lin Ju., and Hussein M. “Incidence and Temporal Pattern of Hospital


57. Stewart S, Murphy N, Walker A. et al. “Cost of an Emerging Epidemic: An

Economic Analysis of Atrial Fibrillation in the UK.” Heart. 2004;90:286-292. 58. Le Heuzey JV, Paziaud O, Piot O et al. “Cost of Care Distribution in Atrial

Fibrillation Patients: The COCAF Study.” American Heart Journal. 2004;147:121-126.





61. Reynolds, Matthew, Essebag V, Zimetbaum P, Cohen D. “Healthcare Resource

Utilization and Costs Associated with Recurrent Episodes of Atrial Fibrillation: The FRACTAL Registry.” J Cardiovasc Elecrophysiol. 2007;18:628-633.

54 |

62. Lee W. Lamas G. Balu S., et al. “Direct treatment cost of atrial fibrillation in


63. Etemad LR, McCollam PL. “Total First Year Costs of Acute Coronary Syndrome

in a Managed Care Setting.” J Manag Care Pharm. 2005;11(4):300-06. 64. Menzin J, Wygant G, Hauch O, Jackel J, Friedman M. “One-year costs of

ischemic heart disease among patients with acute coronary syndromes: findings from a multi-employer claims database.” Curr Med Res Opin. 2008 Feb;24(2):461-8.

65. Bogner HR, Miller SD, de Vries HF, Chhatre S, Jayadevappa R. “Assessment of

cost and health resource utilization for elderly patients with heart failure and diabetes mellitus.” J Card Fail. 2010 June;16(6):454-60. Epub 2010 Mar 6.

66. Kim M., Lin Ju., and Hussein M. “Incidence and Temporal Pattern of Hospital


Corresponding Author:

Erin Sullivan, Ph.D., [email protected]

Independent Advisors:

Joseph Lodato, M.D.

Matt Reynolds, M.D., M.Sc.

Contributors:

Shamonda Braithwaite

Kevin Dietz

Carolyn Hickey

Erin Sullivan, Ph.D.

Avalere Health LLC

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