EFFECT OF THE ANGIOTENSIN-CONVERTING-ENZYME INHIBITOR BENAZEPRIL ON THE PROGRESSION OF CHRONIC RENAL-INSUFFICIENCY

Background. Drugs that inhibit angiotensin-converting enzyme slow the progression of renal insufficiency in patients with diabetic nephropat hy. Whether these drugs have a similar action in patients with other r enal diseases is not known, We conducted a study to determine the effe ct of the angiotensin-converting-enzyme inhibitor benazepril on the pr ogression of renal insufficiency in patients with various underlying r enal diseases. Methods. in a three-year trial involving 583 patients w ith renal insufficiency caused by various disorders, 300 patients rece ived benazepril and 283 received placebo, The underlying diseases incl uded glomerulopathies (in 192 patients), interstitial nephritis (in 10 5), nephrosclerosis (in 97), polycystic kidney disease (in 64), diabet ic nephropathy (in 21), and miscellaneous or unknown disorders (in 104 ), The severity of renal insufficiency was classified according to the base-line creatinine clearance: 227 patients had mild insufficiency ( creatinine clearance, 46 to 60 mi per minute), and 356 had moderate in sufficiency (creatinine clearance, 30 to 45 mi per minute). The primar y end point was a doubling of the base-line serum creatinine concentra tion or the need for dialysis. Results. At three years, 31 patients in the benazepril group and 57 in the placebo group had reached the prim ary end point (P<0.001), In the benazepril group, the reduction in the risk of reaching the end point was 53 percent overall (95 percent con fidence interval, 27 to 70 percent), 71 percent (95 percent confidence interval, 21 to 90 percent) among the patients with mild renal insuff iciency, and 46 percent (95 percent confidence interval, 12 to 67 perc ent) among those with moderate renal insufficiency, The reduction in r isk was greatest among the male patients; those with glomerular diseas es, diabetic nephropathy, or miscellaneous or unknown causes of renal disease; and those with base-line urinary protein excretion above 1 g per 24 hours, Benazepril was not effective in patients with polycystic disease, Diastolic pressure decreased by 3.5 to 5.0 mm Hg in the bena zepril group and increased by 0.2 to 1.5 mm Hg in the placebo group. C onclusions. Benazepril provides protection against the progression of renal insufficiency in patients with various renal diseases. (C) 1996, Massachusetts Medical Society.