Long-term comparison of losartan and enalapril on kidney function in hypertensive type 2 diabetics with early nephropathy

Background. The objectives of this study were to compare the effects of the angiotensin II receptor blocker, losartan. to those of the angiotensin-con verting enzyme inhibitor, enalapril. on albuminuria and renal function in r elationship to clinic and ambulatory blood pressure (ABP) in hypertensive t ype 2 diabetic subjects with early nephropathy. The tolerability of these a gents and their effect on the metabolic profile were also evaluated. Methods. The study was a one-year prospective, double-blind trial with losa rtan and enalapril administered alone or in combination with hydrochlorothi azide and other antihypertensive agents. ABP and renal and biochemical para meters were measured at baseline and after 12. 28. and 52 weeks of active t reatment. Ninety-two hypertensive type 2 diabetics with early nephropathy c ompleted the study. Results. Both losartan and enalapril administered alone or in combination w ith other agents induced significant reductions in sitting clinic (P < 0.05 ) and ABP (P < 0.002) without a statistical difference between groups. Geom etric means for urinary albumin excretion (UAE) decreased significantly (P < 0.001) in patients treated with losartan from 64.1 to 41.5 mu g/min and i n those treated with enalapril from 73.9 to 33.5 mu g/min after 52 weeks of therapy. A significant relationship (P < 0.05) between changes in systolic and diastolic ABP and the decrease in UAE at 52 weeks was seen in both gro ups. The: decline in glomerular filtration rate (GFR) was stabilized at the end of therapy and was identical in both treatment groups. Treatment with enalapril was associated with a significantly higher incidence of cough (P = 0.006) and a rise in serum uric acid (P = 0.002) compared with losartan. Conclusions. Our results indicate that a one-year course of antihypertensiv e therapy with either losartan or enalapril significantly reduces UAE in hy pertensive type 2 diabetic patients with early nephropathy. The reduction i n UAE with each treatment is similarly related to decrements in ABP. In add ition, the rate of decline in GFR is similar in both treatment groups.