Background Nephropathy and retinopathy remain important complications of type 1 diabetes. It is unclear whether early administration of drugs that block the renin-angiotensin system slows their progression. Methods The Renin Angiotensin System Study [RASS] was a multicenter controlled trial in 285 normoalbuminuric, normotensive type 1 diabetic patients who were randomized to losartan (100mg daily), enalapril (20mg daily) or placebo and followed for 5 years. The primary endpoint was change in glomerular mesangial fractional volume in kidney biopsies. The retinopathy endpoint was a 2-step or greater progression in retinopathy severity scale. Intention-to-treat data analyses used linear and logistic regression models. Results Ninety and 82% of patients had complete renal biopsy and retinopathy data, respectively. Change in mesangial fractional volume per glomerulus over 5 years in placebo (0.016 units) was not significantly different from enalapril (p=0.38) or losartan (p=0.26), nor were there significant changes in other biopsy assessed renal structural variables. Five-year cumulative microalbuminuria incidence was higher for losartan than placebo (14% vs. 4%; logrank p=0.015) but not for enalapril (6% vs. 4%; logrank p=0.96). Two-step or more retinopathy progression incidence was reduced by 65% in the enalapril (O.R. 0.35; 95% C.I., 0.14–0.85) and 70% in the losartan group (O.R. 0.30; 95% C.I., 0.12–0.73) independent of changes in blood pressure. There were three biopsy-related serious adverse events that completely resolved. Chronic cough occurred in 12 enalapril, 6 losartan and 4 placebo patients. Conclusions Early renin-angiotensin system blockade did not modify nephropathy progression in type 1 diabetic patients, but had important effects in slowing retinopathy.

No abstract

No abstract