Comparative effects of converting enzyme inhibition and conventional therapy in hypertensive non-insulin dependent diabetics with normal renal function.

The effects of long-term reduction in blood pressure by the angiotensin converting enzyme inhibitor captopril, as single therapy or in combination with hydrochlorothiazide (HCTZ), were compared with those of metoprolol and/or hydrochlorothiazide in 91 hypertensive non insulin-dependent diabetics with normal renal function. Following a single-blind placebo run-in period of 4 weeks, treatments were assigned randomly in a double-blind fashion. During the study, weight and glycosylated hemoglobin remained elevated. After 9 months of treatment, blood pressure fell significantly (p less than 0.0001) in all treatment groups, with most patients achieving goal supine diastolic blood pressure of less than or equal to 85 mmHg. Whereas urinary albumin excretion (UAE) did not change in patients given metoprolol and/or HCTZ, captopril monotherapy (p = 0.0021) or captopril given in combination with HCTZ (p = 0.0002) decreased UAE without affecting glomerular filtration rate. These data are in favour of a renal beneficial effect of angiotensin converting enzyme inhibitors distinct from their effects on systemic blood pressure. Further studies are needed to determine whether this effect persists with longer treatment, and whether it would lead to better preservation of kidney function than other antihypertensive agents.