Combination of ACEI and ARB therapy increases renal risks in elderly

Combining angiotensin-converting-enzyme (ACE) inhibitors with angiotensin-receptor blockers (ARBs) is associated with increased risk of adverse renal outcomes, according to a recent study published in the Canadian Medical Association Journal.

The researchers studied 32,312 new users (mean age, 76.1 years) of an ACE inhibitor, an ARB, or a combination of both medications. Of these patients, 1,750 (5.4%) received combination therapy; however, 1,512 (86.4%) who were given combination therapy did not have trial-established indications such as heart failure or proteinuria.

Patients given combination therapy were more likely to develop renal dysfunction (5.2 events per 1,000 patients per month) than patients given monotherapy (2.4 events per 1,000 patients per month). Hyperkalemia was also more common among patients given combination therapy (2.5 events per 1,000 patients per month) than among those given monotherapy (0.9 events per 1,000 patients per month). Most patients only received combination therapy for a median of 3 months before at least 1 medication was discontinued.

"Our most striking findings were that combination therapy was commonly prescribed for patients who did not have the trial-proven indications and that it was frequently stopped after only a few months, even when hyperkalemia or renal dysfunction did not occur," the researchers concluded.