Brief Report
Ethnic Differences in Risk of Coronary Heart Disease in a Large Contemporary Population

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Introduction

Racial/ethnic differences in diabetes and cardiovascular disease are well documented, but disease estimates are often confounded by differences in access to quality health care. The objective of this study was to evaluate the ethnic differences in risk of future coronary heart disease in patient populations stratified by status of diabetes mellitus and prior coronary heart disease among those with uniform access to care in an integrated healthcare delivery system in Northern California.

Methods

A cohort was constructed consisting of 1,344,899 members with self-reported race/ethnicity, aged 30–90 years, and followed from 2002 through 2012. Cox proportional hazard regression models were specified to estimate race/ethnicity-specific hazard ratios for coronary heart disease (with whites as the reference category) separately in four clinical risk categories: (1) no diabetes with no prior coronary heart disease; (2) no diabetes with prior coronary heart disease; (3) diabetes with no prior coronary heart disease; and (4) diabetes with prior coronary heart disease. Analyses were performed in 2015.

Results

The median follow-up was 10 years (10,980,800 person-years). Compared with whites, blacks, Latinos, and Asians generally had lower risk of coronary heart disease across all clinical risk categories, with the exception of blacks with prior coronary heart disease and no diabetes having higher risk than whites. Findings were not substantively altered after multivariate adjustments.

Conclusions

Identification of health outcomes in a system with uniform access to care reveals residual racial/ethnic differences and point to opportunities to improve health in specific subgroups and to improve health equity.

Introduction

Racial/ethnic differences in diabetes mellitus (DM) and cardiovascular disease are well documented, but population health estimates are often confounded by differences in access to quality health care.1 Inequities and disparities in health outcomes by race/ethnicity and also by income status are persistent and difficult to reduce.2 The IOM report Crossing the Quality Chasm: A New Health System for the 21st Century3 considered equity among six critical features for healthcare quality.

Whereas many studies have shown sizable differences in outcomes between blacks and whites, evidence from the other minority groups is lacking.4 Given the Affordable Care Act’s recent broadening of healthcare access, updated benchmarks established from ethnically diverse populations with uniform healthcare coverage are needed. To address this knowledge gap, and to inform and help reduce health inequalities, this study sought to evaluate ethnic differences in risk of future coronary heart disease (CHD) in patient populations stratified by status of DM and prior CHD in a population with uniform access to care.

Section snippets

Methods

Kaiser Permanente Northern California is a large, integrated healthcare delivery system, caring for >3 million people who are broadly representative of the service area.5, 6 A cohort was constructed of 1,344,899 members with self-reported race/ethnicity, aged 30–90 years at baseline, January 1, 2002, and was followed through December 31, 2012, with censoring after outcome event, end of health plan membership, or death. Individuals were excluded if they were not continuously enrolled during the

Results

The median follow-up was 10 years (10,980,800 person-years). Although 64% of the population was white, there was still a large proportion of Asians (n=190,439); Latinos (n=169,886); and blacks (n=116,273). Whites were older and almost one fifth of blacks were from economically disadvantaged neighborhoods (Table 1).

The exposure of interest included four clinical risk categories defined by presence or absence of diabetes and prior CHD (no DM/no CHD, no DM/prior CHD, DM/no CHD, DM/prior CHD). Race

Discussion

Pervasive racial/ethnic differences in DM, cardiovascular disease, and their risk factors remain an important societal problem.8 It has been suggested that to reduce inequity, healthcare organizations should explore reasons that contribute to disproportionate lack of access.2

Kaiser Permanente is an integrated healthcare delivery system with uniform access to health care, and the present study found slightly reduced or no difference in risk for blacks, Asians, and Latinos compared with whites

Conclusions

Much is still needed to address the differences in health status and outcomes related to race/ethnicity.12 These findings may inform policy development and interventions designed to identify and eliminate racial/ethnic differences.

Acknowledgments

This study was supported by a grant from the Kaiser Permanente Northern California Community Benefit Program, which had no role in the study design or activities.

No financial disclosures were reported by the authors of this paper.

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