Angiotensin II receptor blockade and type 2 diabetic nephropathy

Abstract

ACE inhibitors have been shown to reduce albuminuria and slow the progression of nephropathy in type 1 diabetes. There are fewer data in type 2 patients. Three large studies: IRbesartan in patients with type 2 diabetes and MicroAlbuminuria Study (IRMA2), Irbesartan Diabetic Nephropathy Trial (IDNT) and Reduction in End points in NIDDM with the Angiotensin II Antagonist Losartan (RENAAL), of the angiotensin II receptor blockers (ARBs) irbesartan and losartan in microalbuminuric (IRMA2) and nephropathic (IDNT and RENAAL) patients have recently been published. They compared ARBs to conventional treatment, and one used amlodipine as a comparator (IDNT). IRMA2 showed that irbesartan reduced albuminuria in a dose-dependent fashion, achieving a magnitude of response similar to that seen in type 1 diabetic patients. The adjusted hazard ratio for progressing to nephropathy was 0.32 for patients treated with irbesartan 300 mg. IDNT and RENAAL showed that irbesartan 300 mg or losartan 100 mg reduced by 16—19% the numbers of patients reaching a combined end point of doubling of baseline serum creatinine, end-stage renal failure, or all-cause mortality. This effect was not seen in amlodipine treated patients, implying a specific benefit of ARBs. ARBs should be considered as first line therapy in both early and established type 2 diabetic nephropathy.