Telmisartan is more effective than losartan in reducing proteinuria in patients with diabetic nephropathy

In patients with diabetic nephropathy, lowering blood pressure and reducing proteinuria by over 30% correlates with a slower progression to kidney failure. We compared two different angiotensin receptor-blockers in a double blind, prospective trial of 860 patients with type 2 diabetes whose blood pressure levels was over 130/80 mmHg or who were receiving antihypertensive medication(s) and who had a morning spot urinary protein to creatinine ratio of 700 or more. Patients were randomized to telmisartan (a highly lipophilic agent with a long half-life) or losartan (with low lipophilicity and short half-life). The primary endpoint was the difference in the urinary albumin to creatinine ratio between the groups at 52 weeks. The geometric coefficient of variation and the mean of the urinary albumin to creatinine ratio fell in both groups at 52 weeks but both were significantly greater for the telmisartan compared to the losartan cohort. Mean systolic blood pressure reductions were not significantly different between groups at trial end. We conclude that telmisartan is superior to losartan in reducing proteinuria in hypertensive patients with diabetic nephropathy, despite a similar reduction in blood pressure.