Proteinuria and renal function during antihypertensive treatment for essential hypertension.

In an attempt to determine the effects of antihypertensive treatment on proteinuria and renal function, these factors were studied in 155 patients with essential hypertension, before and during antihypertensive therapy. Slight renal impairment tended to increase with the progress of hypertension, as evidenced by a slight but significant increase in the levels of blood urea nitrogen (BUN) and serum creatinine, and by a progressive decrease in creatinine clearance. A decrease in proteinuria appeared as early as one month after initiation of treatment and continued for at least two years during treatment. Apparently the proteinuria was caused by increased glomerular pressure and by vascular damage in the glomerular vessels. In 7 patients, normalization of blood pressure resulted in an elevation of BUN and creatinine concentrations, although initial renal function did not differ significantly from that in other groups who did not show such derangement during treatment. Thus, a reduction of proteinuria seems to be a good criterion for predicting beneficial results from antihypertensive treatment.