The Renal Protective Effects of Angiotensin II Receptor Blockers in Type 2 Diabetes Mellitus

OBJECTIVE To review the renal protective effects of angiotensin II receptor blockers (ARBs) in patients with type 2 diabetes mellitus. DATA SOURCES A MEDLINE search (1966-March 2004) was completed using irbesartan, candesartan, losartan, valsartan, eprosartan, olmesartan, telmisartan, renal protection, nephropathy, albuminuria, and type 2 diabetes mellitus as key words. STUDY SELECTION AND DATA EXTRACTION All identified English-language articles were reviewed. References of the identified sources were used to identify additional articles. Articles representative of the subject matter of our review were included. DATA SYNTHESIS ARBs have extensive data showing their renal protective benefits in hypertensive type 2 diabetic patients with microalbuminuria or proteinuria. The benefits are over and above that of blood pressure reduction alone and extend to normotensive diabetic patients as well. Maximizing the ARB dose before adding additional therapies or another renal-protecting agent (angiotensin-converting enzyme [ACE] inhibitor or non-dihydropyridine calcium-channel blocker) may be superior to adding another class of antihypertensive, even if similar blood pressures can be achieved. CONCLUSIONS ARBs are an important therapy for hypertensive type 2 diabetic patients and can benefit normotensive diabetic patients as well. ARB dosage optimization or the addition of a second renoprotective agent (ACE inhibitor or non-dihydropyridine calcium-channel blocker) may be important for optimal renoprotection, although further research is clearly needed in this area.