Racial Differences in the Competing Risks of Mortality and ESRD After Acute Myocardial Infarction

Background

The prevalence of earlier stage chronic kidney disease is lower for African Americans than whites in the United States. This is counterintuitive given the known 4-fold greater incidence of end-stage renal disease (ESRD) in African Americans. We describe racial differences in the rate of progression to ESRD and address the competing risk of mortality.

Study Design

Retrospective analysis of Cooperative Cardiovascular Project data.

Setting & Participants

127,736 Medicare beneficiaries 65 years and older admitted to 4,545 hospitals with acute myocardial infarction between February 1994 and June 1995, with follow-up data for ESRD and mortality through June 2004.

Predictors

African American versus white race, estimated glomerular filtration rate (eGFR), and their interaction; other characteristics at hospital admission.

Outcomes & Measurements

Time to ESRD using Cox proportional hazards models.

Results

Mean age was 77.1 years, with 8,278 African Americans (6.5%) and 49.9% women. Mean baseline eGFRs were 61.4 ± 31.4 and 57.0 ± 25.6 mL/min/1.73 m² (P < 0.001) for African Americans and whites, respectively. Of 2,161 patients (1.7%) progressing to ESRD (incidence, 3.75/1,000 person-years), 14.9% were African American. The adjusted hazard ratio for ESRD (African Americans versus whites) was 1.90 (95% confidence interval, 1.78 to 2.03); African Americans were at significantly increased risk of incident ESRD at each baseline eGFR stage (P for interaction < 0.001). Racial differences in incident ESRD were not accounted for by differences in mortality.

Limitations

Retrospective analysis, residual bias from unmeasured factors, baseline eGFR determined from serum creatinine levels at the time of acute hospitalization.

Conclusions

Within a nationally representative sample of Medicare patients with acute myocardial infarction, African Americans had an increased 10-year risk of ESRD regardless of baseline kidney function that was not accounted for by differences in pre-ESRD mortality.

Index Words: African American, chronic kidney disease, end-stage renal disease, health disparities, Medicare