Three studies, recently published in the New England Journal of Medicine, suggest that angiotensin-receptor antagonists may delay kidney failure in patients with Type 2 diabetes. Microalbuminuria and hypertension are both risk factors for diabetic nephropathy. Previously, it had been demonstrated that interruption of the renin-angiotensin system slows the progression of renal disease in patients with Type 1 diabetes, but similar data have not been available for patients with Type 2.

The studies investigated the effects of two angiotensin-receptor antagonists, irbesartan (Avapro) and losartan (Cozaar) and compared the effects of these drugs to either placebo, or to a calcium channel blocker, amlodipine (amlodipine was only investigated in one of the three studies). Primary endpoints varied among the studies but included, the time to onset of diabetic nephropathy; doubling of the base-line serum creatine concentration; development of end-stage renal disease; or death from any cause.

Both medications decreased the risk for development of diabetic nephropathy when compared to placebo, independent of their blood-pressure lowering effects. It is believed that this may be a class effect of all angiotensin-receptor blockers and that ACE inhibitors may have a similar effect.

Sources

1. Lewis, EJ, Hunsicker, LG, Clarke, WR et al. Renoprotective effect of the angiotensin-receptor antagonist irbesartan in patients with nephropathy due to Type 2 diabetes. New England Journal of Medicine. 2001; 345:851-60.
2. Brenner, BM, Cooper, ME, de Zeeuw, D et al. Effects of losartan on renal and cardiovascular outcomes in patients with Type 2 diabetes and nephropathy. New England Journal of Medicine. 2001; 345:861-69.
3. Parving, H, Lehnert, H, Brochner-Mortensen, J et al. The effect of irbesartan on the development of diabetic nephropathy in patients with Type 2 diabetes. New England Journal of Medicine. 2001; 345:870-78.