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 mu mol/L respectively) were significantly higher than those of 1367 whites (108 and 107 mu mol/L), with a small increase of 4 mu mol/L (p<0.01) for blacks and a fall of 0.9 mu mol/L (p>0.05) for whites. Less than 2% of all patients attained or remained at a final serum creatinine of 177 mu mol/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 greater than or equal to 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.