Differences in Survival Between Black and White Patients With Diabetic End-Stage Renal Disease

Abstract

To evaluate whether the longer survival of blacks with diabetic end-stage renal disease (ESRD) relative to whites is due to racial differences in type of diabetes, comorbidity at ESRD onset, and ESRD treatment modality and to examine whether survival differences between blacks and whites occur only in certain population subgroups. The Michigan Kidney Registry was used to ascertain all blacks and whites (n = 594) with diabetic ESRD in southeastern Michigan, with ESRD onset at age < 65 years during 1974-1983. Patients were followed through 1988. Medical records were abstracted for type of diabetes, comorbidity at ESRD onset, and other factors. Median survival among insulin-dependent diabetes mellitus patients was 27 months in blacks and 17 months in whites, and among non-insulin-dependent diabetes mellitus patients was 30 months in blacks and 16 months in whites. After adjustment for confounding factors by Cox proportional hazards analysis, the death rate was 45% lower in blacks than in whites on dialysis (relative death rate [RDR] = 0.55, 95% confidence interval [CI] = 0.44-0.69), but was similar in blacks and whites with a renal transplant (RDR = 0.99, 95% CI = 0.64-1.52). Compared with dialysis, transplantation was associated with lower mortality in both races (white, RDR = 0.50, 95% CI = 0.36-0.70; blacks, RDR = 0.89, 95% CI = 0.60-1.34), although the effect was not statistically significant in blacks. Racial differences in survival did not vary by type of diabetes or any additional factor. Survival after ESRD onset is longer in blacks than in whites treated with dialysis, even after adjusting for comorbidity and other factors that affect survival. Survival does not differ by race among transplant patients.