Renal function during antihypertensive treatment.

To determine the association of renal function and the course of blood pressure in antihypertensive therapy, we studied the changes in serum creatinine as a measure of renal function and in-treatment blood pressure in black and white hypertensive patients. We measured serum creatinine in 2125 mild and moderately hypertensive men during treatment over an average of 5 years. Both unadjusted mean initial and final serum creatinine of 758 blacks (113 and 117 mumol/L respectively) were significantly higher than those of 1367 whites (108 and 107 mumol/L), with a small increase of 4 mumol/L (p < 0.01) for blacks and a fall of 0.9 mumol/L (p > 0.05) for whites. Less than 2% of all patients attained or remained at a final serum creatinine of 177 mumol/L or more. Of this small group (3% blacks, 1.4% whites), 31% had proteinuria at entry. After stratification by in-treatment diastolic blood pressure (< 95 and > or = 95 mm Hg) in each race, mean slopes of reciprocal serum creatinine were estimated, adjusting for age at entry, initial serum creatinine, diastolic pressure, and body-mass index by analysis of covariance. The two adjusted mean slopes did not differ significantly within each race. Multiple regression analysis confirmed that in-treatment diastolic pressure was not independently associated with final serum creatinine. The change in renal function was most likely a reflection of regression towards the mean, and does not support the view that antihypertensive treatment is an important determinant of renal function in mild-to-moderate hypertensive patients. Patients with substantial renal insufficiency may have pre-existing intrinsic renal disease.