EFFECTS OF LONG-TERM ANTIHYPERTENSIVE TREATMENT AND AGING ON RENAL-FUNCTION AND ALBUMIN EXCRETION IN PRIMARY HYPERTENSION

The effects on renal function and urinary albumin excretion of 7 years of antihypertensive treatment compared to the effects of normal aging were studied in a random sample of 40 men with newly diagnosed primar y hypertension and in 17 normotensive men of the same age, respectivel y. The hypertensives were treated with metoprolol either as monotherap y (n = 21) or combined with hydrochlorothiazide or hydralazine. Glomer ular filtration rate (GFR; inulin clearance), renal blood flow (RBF; p ara-aminohippurate clearance), renal vascular resistance (RVR), and th e 24 h urinary albumin excretion were determined. GFR was significantl y reduced from 104 +/- 15 mL/min (mean +/- SD) to 86 +/- 20 mL/min (P < .001) in the hypertensive group, but the reduction was not significa ntly greater than in the normotensive group. As judged from the study of a subgroup of the hypertensives, most of the decrease in GFR occurr ed early as an immediate drug-induced, functionally explained decrease . The changes in RBF and RVR after 7 years of treatment did not differ significantly from those due to normal aging. RVR remained higher and RBF remained lower in the hypertensives than in the normotensives. Th e urinary albumin excretion in the hypertensives was significantly red uced after 7 years but remained higher than in the normotensives. In c onclusion, the changes in renal function and hemodynamics seen after l ong-term treatment with metoprolol in primary hypertension were not si gnificantly different from the changes caused by normal aging in normo tensives.