Placebo-controlled trial of lisinopril in normotensive diabetic patients with incipient nephropathy

To study the effects of an angiotensin converting enzyme inhibitor, lisinopril, on renal function in incipient diabetic nephropathy, a prospective double-blind randomised placebo-controlled single centre study was set up at our outpatient diabetic-renal clinic. There were 27 patients with Type I and Type II diabetes with an albumin excretion rate of between 20 micrograms/min and 200 micrograms/min, respectively and no hypertension. Intervention treatment with placebo or low dose lisinopril was for 48 weeks. The main outcome changes were in urinary albumin excretion rate, urinary prostaglandin excretion, and glomerular filtration rate. Secondary outcome measures included changes in BP and heart rate. Of the 32 patients entered into the study, 27 completed 48 weeks treatment (12 lisinopril, 15 placebo). Mean (+/- SD) urinary albumin excretion rate fell from 57.6 (25.7) micrograms/min (n = 15) at visit 1 to 26.8 (26.7) micrograms/min (n = 12) at visit 7 after 48 weeks treatment in the lisinopril group but not in the placebo group: 119.2 (116.6) micrograms/min (n = 17) vs. 113.7 (77.0) micrograms/min (n = 15). There was a least squares mean treatment difference of -67.6 micrograms/min (95% confidence interval (CI), -115.0 to -20.2, P < 0.01) in favour of lisinopril compared with placebo. After 48 weeks treatment seven lisinopril treated patients were normoalbuminuric and five were microproteinuric; three placebo treated patients were normoalbuminuric, nine were microalbuminuric and three were macroproteinuric. Excretion of prostaglandin-F1 alpha (PGF1 alpha) and thromboxane-B2 (TXB2) fell in the lisinopril treated group.(ABSTRACT TRUNCATED AT 250 WORDS)