Prevalence of hypertension in diabetes mellitus--its relation to diabetic nephropathy

The prevalence of hypertension was studied in 374 patients with non-insulin dependent diabetes mellitus (NIDDM) and in 1197 non-diabetic controls. The diagnosis of hypertension was made when the mean systolic pressure of three measurements on different occasions was 151 mmHg or greater, or the mean diastolic pressure was 91 mmHg or greater. The prevalence was 42.8% in the diabetics and 17.8% in the controls. It showed a significant difference over age 31 (p less than 0.05). Proteinuria (p less than 0.001), abnormal ECG (p less than 0.01), hyperlipidemia (p less than 0.05) and hypertensive or sclerotic changes of the retina (p less than 0.001) were more frequently observed in the diabetics than in the controls. Hypertension was found in 71% of those with proteinuria, 48% with diabetic retinopathy, 61% with abnormal ECG and 54% with hyperlipidemia in the diabetics. The incidence of proteinuria was 22.8% in the diabetic hypertensives and was 8.3% in the non-diabetic hypertensives (p less than 0.001). 24 subjects out of 119 diabetics, who were normotensive at their initial visits, became hypertensive within 10 years (N-H), and 95 remained normotensive (N-N). 38% of N-H showed proteinuria already on their initial examinations and 3% of N-N did. 73% of those who showed proteinuria on their initial examination became hypertensive and 13% of those who were free from proteinuria did (p less than 0.001). The results suggest that diabetic nephropathy plays an important role in developing hypertension in diabetics.