Survival Advantage of Black Patients with Kidney Disease after Acute Myocardial Infarction

Abstract

Black individuals have a disproportionate incidence of ESRD when compared with white individuals, and among patients with ESRD, black patients experience better survival. The aim of this analysis is to assess, in a nationally representative sample of patients with cardiovascular disease, ethnic differences in survival among predialysis patients with kidney disease. A retrospective cohort analysis was conducted of Cooperative Cardiovascular Project data of Medicare patients who were aged >65 yr and admitted for incident acute myocardial infarction and had 3 yr of mortality follow-up. Cox regression models and Kaplan Meier estimates were performed to examine differences in survival between black and white patients stratified by severity of kidney disease. Of 57,942 patients, 7.3% were black. Black patients were younger and more likely to be female and were less likely to have decreased kidney function. A significant interaction between race and kidney function existed with respect to mortality among patients who survived to discharge. The adjusted hazard ratios for death, black compared with white patients, were 1.00 (95% confidence interval 0.90 to 1.11) among patients with a GFR ≥60 ml/min per 1.73 m² and decreased monotonically among patients with lower GFR to 0.79 (95% confidence interval 0.61 to 0.97) among patients with a GFR 15 to 29 ml/min per 1.73 m². Among patients with incident acute myocardial infarction, black patients with more severe kidney disease, when compared with their white counterparts, experience better survival. Further investigation into the reasons for ethnic differences in survival and progression of kidney disease is warranted.