Long-term renal function in primary hypertension. An epidemiological and pathophysiological study.

The purpose of this study was to investigate the influence of birth factors on adult blood pressure and to study the long-term renal function and hemo dynamic changes in primary hypertension. The investigations were performed in two population-based samples of men derived from two large screening inv estigations on blood pressure, a screening investigation of 49-year-old men and the Primary Prevention Study. Birth variables were studied in 430 subjects, born in 1926-27, who had part icipated in the screening investigation of 49-year-old men in Goteborg. The 14-year follow-up study of renal function and haemodynamics and urinary albumin excretion was performed in a stratified random sample of normotens ive (n = 11) and hypertensive (n = 23) 49-year-old men. The effects of intensified blood pressure control (to a diastolic blood pre ssure, DBP less than or equal to 85 mmHg) on renal function, haemodynamics and urinary albumin excretion, achieved by addition of felodipine or ramipr il to ongoing treatment with beta-blockade, were investigated in 28 hyperte nsives. To determine if treated primary hypertension can lead to end-stage renal di sease, the development of serum creatinine levels during 20 years in 686 hy pertensive men from the Primary Prevention Study, recruited from a random t hird of the male population aged 47-55 years at entry, was studied. The findings demonstrate that preterm birth (gestational age less than 38 w eeks) seemed to increase the risk of hypertension in adult Life. They also showed, that good long-term blood pressure control (DBP less than or equal to 90 mmHg) in primary hypertension can protect the kidneys from abnormal p rogressive decline in glomerular filtration rate and arrest proteinuria but does not normalise the reduced renal blood flow or the increased renal vas cular resistance seen in primary hypertension. On decreasing the DBP to less than or equal to 85 mmHg, achieved by additio n of felodipine to ongoing treatment with beta-blockade, renal blood flow i ncreased and renal vascular resistance decreased to levels no longer signif icantly different from normal. Addition of ramipril to beta-blockade reduce d blood pressure less and renal function and haemodynamics did not normalis e, but the urinary albumin excretion was lowered. The median value for the urinary albumin excretion remained within the range of the urinary albumin excretion of the normotensives in both the felodipine and the ramipril-trea ted groups. In the Primary Prevention Study, none of the hypertensives developed a hype rtensive end-stage renal disease and only a few patients showed a slight in crease in serum creatinine level before the age of 70. Thus, white patients with non-malignant primary hypertension without underl ying renal disease and with good blood pressure control do not appear to de velop progressive decline in kidney function or hypertensive end-stage rena l disease.