EPIDEMIOLOGY OF HYPERTENSION IN DIABETIC-PATIENTS AND IMPLICATIONS FOR TREATMENT

We review the epidemiology of hypertension in diabetic patients and discuss the implications for treatment. The relationship between coronary heart disease (CHD) mortality and blood pressure (BP) in the World Health Organization Multinational Study of Vascular Disease in Diabetics (WHO MSVDD) is evaluated. One thousand two hundred seventy-seven patients with insulin-dependent diabetes mellitus (IDDM) and 3463 patients with non-insulin-dependent diabetes mellitus (NIDDM), aged 35-55 yr at baseline, from 10 centers throughout the world were evaluated. CHD mortality after a follow-up of 6-7 yr was measured. Estimates of usual diastolic BP were made with data from the Framingham study. The relative risk (RR) of CHD death was plotted against usual diastolic BP for IDDM and NIDDM, and the shapes of the relationship were compared with a meta-analysis of nine prospective studies in nondiabetic populations. For the NIDDM group, the CHD RRs were significantly > 1.0 only for the uppermost diastolic BP category (RR 2.23, 95% confidence interval 1.14-4.40). For the IDDM group, the shape of the diastolic BP-CHD relationship was difficult to assess in view of the small number of events. In neither diabetic group was the evidence for a J-shaped relationship. Elevated BP is associated with increased cardiovascular/renal mortality in both types of diabetes. However, the efficacy of antihypertensive therapy in the prevention of these outcomes remains unclear. Prospective data from the WHO MSVDD do not provide clear evidence of benefit from treating diastolic BP < 95-100 mmHg in NIDDM patients. The cost-benefit implications of aggressive BP treatment in IDDM must be more clearly defined before such treatment policies are accepted.