Dual therapy with angiotensin-converting–enzyme inhibitors plus angiotensin-receptor blockers was no better than monotherapy.

Some clinicians prescribe combinations of angiotensin-converting–enzyme (ACE) inhibitors plus angiotensin-receptor blockers (ARBs) for patients with type 2 diabetes, on the premise that dual blockade of the renin–angiotensin system will slow progression of diabetic nephropathy more effectively than single-agent therapy. In this study, researchers randomized 133 type 2 diabetic patients with nephropathy to receive lisinopril (titrated to 40 mg daily), irbesartan (titrated to 600 mg daily), or combined therapy (titrated to 20 mg and 300 mg, respectively). Inclusion criteria included stage 2 or 3 kidney disease and urine protein-creatinine ratio >300 mg/g. At baseline, mean blood pressure was 153/81 mm Hg, and mean serum creatinine level was 1.5 mg/dL.

After a median follow-up of 32 months, the incidence of the primary composite endpoint (50% increase in serum creatinine level, progression to end-stage renal disease, or death) was virtually identical in the three groups (30%). Frequencies of each of the three individual endpoints and degree of blood pressure lowering also were similar in all groups.

Comment: This study, although small, suggests that combining an ACE inhibitor and an ARB confers no benefit in type 2 diabetic patients with nephropathy. Recall that, in the huge ONTARGET trial (in which enrolled patients had atherosclerotic disease or diabetes), an ACE inhibitor plus an ARB also failed to delay progression of renal dysfunction compared with an ACE inhibitor alone (JW Gen Med Sep 2 2008).

Source: Journal Watch General Medicine