Effect of hypertension on mortality in Pima Indians

Background-The effect of hypertension on mortality was examined in 5284 Pim a Indians, 1698 of whom had type 2 diabetes at baseline or developed it dur ing follow-up. Methods and Results-During a median follow-up of 12.2 years (range, 0.01 to 24.8 years), 470 nondiabetic subjects and 488 diabetic subjects died. In t he nondiabetic subjects, 45 of the deaths were due to cardiovascular diseas e, 208 to other natural causes, and 217 to external causes; in the diabetic subjects, 106 of the deaths were due to cardiovascular disease, 85 to diab etic nephropathy, 226 to other natural causes, and 71 to external causes. I n the nondiabetic subjects, after adjusting for age, sex, body mass index, and serum cholesterol concentration in a proportional hazards model, hypert ension predicted death from cardiovascular disease (death rate ratio [DRR]= 2.8; 95% CI, 1.4 to 5.6; P = 0.003). In the diabetic subjects, after addit ional adjustment for duration of diabetes, plasma glucose concentration, an d proteinuria, hypertension strongly predicted deaths from diabetic nephrop athy (DRR = 3.5; 95% CI, 1.7 to 7.2; P < 0.001), but it had little effect o n deaths from cardiovascular disease (DRR = 1.4; 95% CI, 0.88 to 2.3; P = 0 .15). Conclusions-We propose that the weak relationship between hypertension and cardiovascular disease in diabetic Pima Indians is not because of a diminis hed effect of hypertension on cardiovascular disease in diabetes, but becau se of a relatively greater effect of hypertension on the progression of dia betic nephropathy. Factors-that may account for this finding in Pima Indian s include a younger age at onset of type 2 diabetes, a low frequency of hea vy smoking, favorable lipoprotein profiles and, possibly, enhanced suscepti bility to renal disease.