Sixteen-year coronary mortality in black and white men with diabetes screened for the Multiple Risk Factor Intervention Trial (MRFIT).

BACKGROUND: Risk of coronary heart disease (CHD) mortality associated with diabetes is high and it is unclear to what extent the high mortality is due to modifiable risk factors. To explore this, mortality and predictors of CHD death are compared in a large cohort of black and white men with diabetes.

METHODS: In all, 610 black and 3997 white men who reported taking medication for diabetes and had no history of hospitalization for heart attack were screened by 22 centres for the Multiple Risk Factor Intervention Trial (MRFIT). At screening major risk factors for CHD were determined. Participants have been followed for an average of 16 years for vital status. Cause-specific mortality and predictors of CHD are compared for blacks and whites using proportional hazards regression.

RESULTS: Serum cholesterol and systolic blood pressure levels were similar in blacks and whites with diabetes, while diastolic blood pressure and percentage of smokers were higher in blacks (89 versus 86 mmHg and 47% versus 34%) and median income was lower. Coronary heart disease was the leading cause of death, accounting for 31% (68/221) and 44% (564/1293) of deaths among blacks and whites, respectively. Adjusted relative risks of CHD death and all cause mortality for blacks compared to whites were 0.71 (95% CI: 0.53-0.95) and 0.94 (95% CI: 0.75-1.11). Differences in reporting cause of death probably account for some of the black/white difference in CHD. High serum cholesterol, high blood pressure, and smoking increased risk of CHD death similarly in blacks and whites.

CONCLUSIONS: Serum cholesterol, blood pressure, and smoking are major influences on CHD mortality risk in both white and black men with diabetes. High prevalence of these factors indicates substantial potential for CHD prevention in both ethnic groups.