Racial and Ethnic Differences in the Quality of Care for Patients Hospitalized

with Myocardial Infarction, 1999-2002.

Elizabeth H. Bradley, PhD

Yale School of Public Health

Acknowledgements

This work is funded by

-National Heart, Lung, and Blood Institute (#R01HS10407-01)

-Patrick & Catherine Weldon Donaghue Medical Research Foundation (#02-102)

-Claude D. Pepper Older Americans Independence Center at Yale (#P30AG21342)

Collaborators

Jeph Herrin, PhDYongfei Wang, MS

Robert McNamara, MDTashonna Webster, MPH

David Magid, MDMartha Blaney, PharmD

Eric Peterson, MDJohn Canto, PhD

Charles Pollack, MDHarlan Krumholz, MD

Background

Many studies demonstrate different patterns of cardiovascular care by racial and ethnic groups (e.g., referral for cardiac catheterization, use of invasive tests)

Few have investigated the relative contributions of socio-demographic, economic, clinical, and health system features to this racial/ethnic disparities

Why is this important?

Elimination of racial/ethnic disparities in care is a national priority (IOM, CDC, AHRQ)

To address disparities, we have to know their source and causal mechanisms

Research objectives

We sought to:

Characterize racial/ethnic differences in quality of cardiovascular care for patients hospitalized with acute myocardial infarction (AMI)

Examine factors that mediate or explain observed racial/ethnic differences in quality of care

Measuring quality of care for AMI

Which quality indicator to use?

- Evidence based

- Well established in clinical guidelines

- Substantial variation in country

- Involving hospital “systems”

Time is muscle!

Quality indicator endorsed by American Heart Assoc is time to acute reperfusion

- 30 minutes door to drug (“lytics”)

- 90 minutes door to balloon (PCI)

Study design and sample

Retrospective, observational study using patient data from the National Registry of Myocardial Infarction, 1999-2002

- fibrinolytic cohort n=73,032; 1,052 hospitals

- PCI cohort n=37,143; 434 hospitals

American Hospital Association Annual Survey of Hospitals, 2000.

Measurement: outcome

Door-to-drug time; door-to-balloon time as continuous measures

Log transformed for performing parametric analyses, in order to account for the skewness of its distribution

Summary measures thus reported as geometric (i.e., logarithmic) mean

Measurement: race/ethnicity

Recorded by admissions clerk or nurse; a set of dummy variables

WhiteAfrican American/BlackHispanicAsian/Pacific IslanderAmerican Indian/Alaska nativeOther/Unknown

Statistical analysis

We examined overall geometric means for door to treatment times for each racial/ethnic group, i.e., “crude” differences

To explore how crude differences might be mediated by other factors, we employed multivariate, hierarchical models (built in sequence of steps)

Results

Crude rates (mins) DTD DTB

TARGET 30 mins 90 mins

White 33.8 103.4

Afr Am 41.1** 122.3**

Hispanic 36.1** 114.8**

Asian 37.4** 105.8

Am Ind 36.4 101.2

Other 33.9 101.2** P-value < 0.01

Door to balloon times: AfricanAmerican (differences from white)

Race/ethnicity effects Compared to white

Overall crude 18.9 minutes

+Hosp cluster effects 12.6 minutes

+Age, sex, ins 12.9 minutes

+Clinical char 11.1 minutes

+Full model 8.6 minutes

Door to balloon times: AfricanAmerican (differences from white)

Of the 18.9 minute crude difference,

- 33.3% (18.9 -12.6/18.9) accounted for by hospital-specific effect

- 21.2% (12.6 - 8.6/18.9) accounted for by patient-level factors and hospital

characteristics - 45.5% (8.6/18.9) independently related to

race/ethnicity

Door to balloon times: Hispanic (differences from white)

Race/ethnicity effects Compared to white

Overall crude 11.4 minutes

+Hosp cluster effects 3.2 minutes

+Age, sex, ins 4.9 minutes

+Clinical char 4.4 minutes

+Full model 3.7 minutes

Door to balloon times: Hispanic (differences from white)

Of the 11.4 minute crude difference,

- 71.9% (11.4 - 3.2/11.4) accounted for by hospital-specific effect

- some negative confounding by sex, age

- 32.5% (3.7/11.4) independently related to race/ethnicity

Discussion

Marked differences in time to reperfusion by racial/ethnic group

Especially apparent for African Americans, whose door-to-drug and door-to-balloon times are 20% longer than for patients identified as white

Discussion

Is the racial/ethnic disparity a result of:

- differential treatment inside the hospital

- selection to different types of hospitals?

Discussion

We found that a substantial portion of the differences in time to acute reperfusion time was explained by accounting for the hospital to which patients were admitted, especially for Hispanic individuals (~70% of the door-to-balloon time disparity) but also for African American patients (~30% of the disparity)

Implications

Efforts to raise awareness of racial/ethnic disparities are important; however…

These data suggest need for parallel efforts directed at improving the care at hospitals where minority groups receive care

A systemic approach will be needed