Renin-Angiotensin System (RAS) blockers alone or in combination have similar effects on cardiovascular and renal outcomes in patients with diabetes

Angiotensin-Converting Enzyme (ACE) inhibitors and Angiotensin Receptor Blockers (ARBs) alone or in combination have similar effects on cardiovascular and renal outcomes in patients with diabetes, according to a study published by Ferrán Catalá-López and colleagues from the University of Valencia/CIBERSAM and INCLIVA Health Research Institute, Spain, and the Ottawa Hospital Research Institute, Canada, in this week's PLOS Medicine.

A collaboration of researchers from Canada, USA, Italy and Spain combined data from 71 published and unpublished randomized controlled trials (total of 103,120 participants) that tested the effects of renin-angiotensin system (RAS) blockers alone or in combination with other high blood pressure treatments in adults with diabetes. Using a novel analytic approach called network meta-analysis, the researchers found no significant differences in the risk of major cardiovascular outcome between ACE inhibitors, and either ARBs or a combination of ACE inhibitors plus ARBs. Similarly, for the risk of progression of renal disease, no significant differences were detected between ACE inhibitors and any of the remaining therapies, such as ARBs or a combination of ACE inhibitors plus ARBs. They also found that no RAS blocker strategy was superior to ACE inhibitors with respect to all-cause mortality, cardiovascular mortality, heart attacks, end-stage renal disease, or doubling serum creatinine.

While the findings suggest that any single ACE inhibitor or ARB was equally effective as any other, and just as effective as any drug combination, there were not enough data comparing direct renin (DR) inhibitors with ACE inhibitors or ARBs to allow strong conclusion, therefore additional research might be warranted. Furthermore, the analyses did not consider the costs of any particular drug, or any side effects that were not relevant to the outcomes measured.

The authors say: "Clinicians should discuss the balance between benefits, costs, and potential harms with individual diabetes patients before starting treatment."