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Clinical Studies using Diagnosis Procedure Combination (DPC) Database

Hideo Yasunaga, MD, PhDDepartment of Health Management and Policy,

Graduate School of Medicine, University of Tokyo

What is DPC?Japanese version of Diagnosis Related Groups

Diagnosis Procedure Combination (DPC) is a diagnosis-dominant case-mix system, comprised of 18 major diagnostic categories (MDC), 520 diagnostic groups, and 2,347 case-mix groups.

18 Major Diagnosis GroupMDC 01 Central nervous systemMDC 02 EyesMDC 03 Ears, Nose and ThroatMDC 04 Respiratory systemMDC 05 Cardiovascular system

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520 Diagnosis GroupsMajor Diagnosis Group 05(Cardiovascular system)

050030 Acute Myocardiac Infarction050050 Angina Pectoris050060 Cardiomyopathy050080 Valvular Diseases

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2,347 DPC050030(Acute myocardiac infarction)

AMI, tPA, Coronary stent⇒ 050030xx03x3xxAMI, IABP, CABG ⇒ 050030xx02x4xx

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The DPC Database is a patient discharge and administrative claims database.

Data are compiled between July and December each year by the DPC Research Group (Chief: Shinya Matsuda MD, PhD) funded by the Ministry of Health, Labour and Welfare, Japan.

The DPC Database

Administrative Claims Database in the US

(1)Nationwide Inpatient Sample (NIS) Database-includes 8 million patients per year from 1,044 hospitals in 40 states, representing approx. 20% of all inpatients in the US.

(2) Medicare Claim Database-includes all patients ≥ 65 yrs-linked with Surveillance, Epidemiology and End Results (SEER) program of cancer registries(SEER-Medicare Linked Database).

Japanese DPC Database includes around 3 million inpatients per half a year, representing approx. 45% of all acute care inpatients in Japan.

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DataThe database include patient information on -Diagnoses coded with the ICD-10 codes-Procedures -Comorbidities at admission (入院時併存症)-Complications after admission (入院後合併症)-Drugs and Devices used-In-hospital mortality(在院死亡)-Length of stay(在院日数)-Costs

-Cancer stage, Chemotherapy, Radiotherapy-Coma Scale-ASA, NYHA, Hugh-Jones, Child-Pugh-Burn Index-Pregnancy-Smoking indexetc.

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Clinical Statisticsusing the DPC Database

Operative Mortality following Cancer Surgery 2007(がん手術後の在院死亡率)

N inhospital death %Lung 17,341 173 1.00%Esophagus 3,327 152 4.57%Stomach 31,910 512 1.60%Liver 10,026 271 2.70%Pancreas 6,123 196 3.20%Colon 27,958 609 2.18%Rectum 17,927 321 1.79%Kidney 8,413 76 0.90%Bladder 2,418 49 2.03%Prostate 7,908 4 0.05%Uterus 7,501 18 0.24%

50-59yrs 60-69yrs 70-79yrs ≥80yrsLung 0.5% 0.7% 1.3% 2.1%Esophagus 2.7% 3.3% 7.3% 10.0%Stomach 0.6% 1.0% 1.8% 3.9%Liver 1.6% 2.3% 3.7% 4.5%Pancreas 1.4% 2.9% 4.0% 6.6%Colon 1.0% 1.3% 2.2% 4.6%Rectum 0.6% 1.0% 2.5% 4.6%Bladder 0.0% 1.4% 3.0% 3.1%Uterus 0.3% 0.2% 0.6% 1.0%

Operative Mortality following Cancer Surgery 2007

Surgical Volume and Operative Outcomes(手術件数と手術成績）

Studies have indicated that higher operative caseload volume is associated with lower surgical mortality after complex surgical procedures.

However, little is known about the relationship between operative volume and postoperative complications.

Postoperative complications followingNephrectomy for Renal Cancer (n=7988)Urinary tract infection 117 (1.5%)Ileus 103 (1.3%) Surgical site infection 97 (1.2%) Cardiac events 87 (1.1%) Sepsis 63 (0.8%) Respiratory complications 58 (0.7%) Renal failure 46 (0.6%) Venous thromboembolism 44 (0.4%) Pancreatitis 21 (0.3%) Stroke 17 (0.2%) Peritonitis 14 (0.2%)

Overall, 595 patients (7.4%) had at least one complication.The in-hospital rate of death was 0.84% (n=67).

Age and Outcomes

Hospital volume and outcomes

*Hospital volume: the annual number of nephrectomy perfomed at each hospital

Multivariate regression

Incidence of Malignant Hyperthermia(悪性高熱)

Malignant hyperthermia (MH) is a life-threatening pharmacogenetic disease that occurs during general anesthesia.

A potential risk of MH is the use of volatile anesthetic agents (揮発性麻酔薬) and muscle relaxants (筋弛緩薬).

The true incidence of MH remains unclear because of a paucity of universal reporting.

N % MHIncidence

(per million)Total 1,238,171 100.0% 17 13.7 Volatile agents Sevoflurane 932,771 75.3% 14 15.0 Isoflurane 33,231 2.7% 0 0.0 Halothane 682 0.1% 0 0.0 Enflurane 35 0.0% 0 0.0 Muscle Relaxants Suxamethonium 19,871 1.6% 0 0.0 Vecuronium 782,899 63.2% 10 12.8 Pancuroneum 11,286 0.9% 0 0.0 Rocuronium 246,572 19.9% 6 24.3Propofol 949,694 76.7% 12 12.6

Incidence of MH determined with the DPC database17 MH detected among 1,238,171 patients undergoing general anesthesia.

Impact of Drug-eluting Stents (DES) on Treatment Option Mix for Coronary Artery Disease in Japan

Percutaneous coronary intervention (PCI)-Bare metal stent (BMS)-Drug-eluting stent (DES)

Coronary artery bypass grafting(CABG) -on-pump CABG-off-pump CABG

DES was introduced in September 2004 in Japan.

PCI:percutaneous coronary intervention, CABG：coronary artery bypass graftingDES：drug eluting stents，BMS：bare metal stents

4-year trend in proportions of therapeutic options for Angina Pectorisfrom 144 hospital in July, 2004-2007

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DES not only replaced BMS, but also expanded patients’ eligibility for PCI.

Increase in PCI was concurrent with a temporary reduction in on-pump CABG but in the increase in off-pump CABG.

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The Effect of Mechanical Thromboprophylaxis for Pulmonary Embolism following Abdominal Cancer Surgery

（腹部がん手術後の肺塞栓症に対する間欠的空気圧迫装置による予防効果）

N PE % N PE %Overall 18,630 38 0.20% 52,231 85 0.16%Gastrectomy 5319 5 0.09% 16070 24 0.15%Colectomy 4849 7 0.14% 15233 20 0.13%Rectal surgery 3070 9 0.29% 9003 12 0.13%Hepatectomy 1751 4 0.23% 3391 5 0.15%Nephrectomy 1474 7 0.47% 3531 13 0.37%Prostatectomy 1376 4 0.29% 3070 5 0.16%Hysterectomy 1202 3 0.25% 2917 7 0.24%

No prophylaxis Mechanical prophylaxis

Incidence of Perioperative Pulmonary Embolism in the groups with and without mechanical prophylaxis

Logistic regressionodds ratio p

Duration of anesthesia ≤180 181 - 240 1.07 0.42 - 2.72 0.893 241 - 300 2.00 0.84 - 4.75 0.117 301 - 360 2.24 0.90 - 5.54 0.081 >360 4.43 1.90 - 10.32 0.001Thromboprophylaxis None Mechanical thromboprophylaxis 0.53 0.31 - 0.92 0.025

Reference

Reference

95% confidence interval

Measles in Japan, 2007-2008

America was declared free from endemic measles transmission in 2002.In Europe, 29,000 measles infections were reported in 2004.In Japan, measles outbreaks occurred in 2001 and 2007.

Measles sometimes accompanies diverse complications, including pneumonia, otitis media, and central nervous system involvement.

We searched for measles-related complications and hospitalizations in Japan in 2007-2008, using the DPC Database.

≤14 15-29 ≥30 AllAny complication (%) 6.6 4.2 3.7 4.8Pneumonia (%) 5.2 1.8 1.4 2.8Encephalitis (%) 0.3 1.0 0.7 0.7Meningitis (%) 0.0 0.1 0.5 0.2Intestinal complications (%) 0.2 0.3 0.1 0.2Conjunctivitis (%) 0.3 0.1 0.3 0.2Otitis media (%) 0.2 0.1 0.0 0.1Other complications (%) 0.4 0.8 0.7 0.6

Age (years)

Measles Complications

Age Distribution

Age distribution revealed two peaks in ≤4 and 15-29 years old.Measles-mumps-rubella （MMR）vaccine failure in late 1980s and early 1990s could be associated with the high incidence in patients aged 15-29 years.

Venomous snake bites in JapanAbout 15% of 3000 species of snakes worldwide are venomous, including rattlesnakes, cottonmouths and copperheads in North America, cobras, mambas and kraits in tropical zones,and mamushi (A. blomhoffii) and habu (T. flavoviridis) in Japan.

←Crotalidae species (pit vipers) with a triangular head, elliptical pupils, and retractable fangs(NEJM2002;347:347-56)

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352

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171

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July Aug Sep Oct Nov Dec

20072008

Mamushi and Habu bites (N=1,670)

n %RegionNorthern area

Hokkaido 8 0.5Tohoku 71 4.3

Central areaKanto 143 8.6Chubu 285 17.1

Western areaKinki 210 12.6Chugoku 243 14.6Shikoku 105 6.3

Southern areaKyushu 522 31.3Okinawa islands 60 3.6

n %Local complicationsWound infection 35 2.1Compartment syndrome 31 1.9Systemic complicationsShock 77 4.6Disseminated intravascular coagulation 29 1.7Rhabdomyolysis 52 3.1Acute renal failure 55 3.3Death 3 0.2

Snake venom increases capillary membrane permeability, which leads to extravasation of electrolytes, albumin, and red blood cells into the bite site. Edema, hypoalbuminemia, and hemoconcentration can result in hypovolemic shock and acute renal failure.

Health service researchesusing the DPC database

Researchers can utilize the DPC database to identify, track, and analyze national trends in healthcare utilization, access, outcomes and costs.

The data can be utilized to make a better allocation of healthcare resources.

Framework for clinical epidemiological studies using the DPC database

Clinical experts Epidemiologists

Study DesignData extractionData screening

Discussion

PaperworkAnalysis

Development of the DPC database

Increase in the coverage rateImprovement of usability for researchersLinkage with other database-Outpatient database-Cancer registry -Long-term care database