HOSPITALIZATION FOR CONGESTIVE-HEART-FAILURE - EXPLAINING RACIAL-DIFFERENCES

Objective.-To determine whether the higher rate of hospitalization amo ng African Americans for congestive heart failure (CHF) could be expla ined by racial differences in the prevalence of clinical risk factors for CHF. Design.-Retrospective cohort study. Setting.-A large health m aintenance organization (HMO). Patients.-A sample of 64 877 enrollees (27% African American and 73% white) of the Northern California Kaiser Permanente Medical Care Program who took at least one multiphasic hea lth checkup (MHC) at or after the age of 40 years and were free of CHF at that time. Main Outcome Measures.-First hospitalization with a pri ncipal diagnosis of CHF. Results.-Among cohort members younger than 60 years at baseline MHC, the age-adjusted risk ratio (RR) (African Amer ican/white) for CHF hospitalization was 2.14 for men and 2.73 for wome n, while for persons 60 years of age and older at MHC, the age-adjuste d RR was 1.48 for both sexes. Cox proportional hazards models were use d to adjust for risk factors and length of follow-up. In persons aged 60 years and older, the race difference was explained by greater preva lence of hypertension and diabetes in African Americans (RR=1.12; 95% confidence interval [CI], 0.94 to 1.34 after adjustment for hypertensi on and diabetes). In those younger than 60 years, findings differed by sex. For men, African-American race was no longer a significant predi ctor of CHF after adjusting for hypertension, diabetes, left ventricul ar hypertrophy on electrocardiogram, and body mass index (adjusted RR= 1.16; 95% CI, 0.86 to 1.56). However, among younger women, African Ame ricans continued at increased risk despite adjustment for these variab les as well as smoking, plasma cholesterol, renal function, alcohol us e, and myocardial infarction (adjusted RR=1.49; 95% CI, 1.00 to 2.21). Conclusions.-In this HMO population, the race differences in first ho spitalization for CHF are largely explained by known clinical and beha vioral risk factors, although in younger women these risk factors do n ot completely explain the excess risk among African Americans. These f indings highlight the role of hypertension and diabetes in the develop ment of CHF, particularly among African Americans.