The Effects of Race and Region on Cardiovascular Morbidity Among Elderly Americans With Diabetes

OBJECTIVE: There is conflicting evidence about whether nonwhite Americans with diabetes have an increased risk of cardiovascular disease (CVD). Because geographic region is known to influence the risk of CVD in the U.S., we sought to determine the effects of race and region on cardiovascular morbidity among elderly Americans with diabetes. RESEARCH DESIGN AND METHODS: We performed a national, retrospective, cohort study using the Medicare claims of 126,153 white and 17,962 black patients with diabetes, aged > or =65 years in 1994, who were followed through 1999 for incident acute myocardial infarction, ischemic heart disease, stroke, and heart failure. The effect of race, sex, and region on the incidence of these diseases was assessed using Cox proportional hazards regression, adjusting for baseline demographics and comorbidities. RESULTS: The incidence of any CVD ranged from 23.9/100 person-years among southern black men to 29.2/100 person-years among non-southern black women. The risk of CVD was lower among southern black men (hazard ratio 0.87 [95% CI 0.82-0.92]) and women (0.95 [0.91-0.99]) than their southern white counterparts. In the three other U.S. regions combined (northeast, midwest, and west), black men had a similar risk for CVD (1.01 [0.95-1.07]), and black women had a greater risk (1.10 [1.05-1.16]) than non-southern white men and women, respectively. CONCLUSIONS: Among elderly Americans with diabetes, the incidence of CVD is unlikely to differ a great deal between whites and blacks. Residence in the South seems to confer a modest benefit for elderly black people with diabetes.