According to clinical practice guidelines, the first-line treatment for patients hospitalized with pneumonia is combination therapy with the antibiotic class macrolides, including azithromycin. But recent evidence has also linked azithromycin with an increased risk of such cardiovascular events as myocardial infarction, heart failure, and cardiac arrhythmias.

A team that was led by Eric M. Mortensen, MD, MSc, studied nearly 65,000 older patients hospitalized with pneumonia (JAMA. 2014;311[21]:2199-2208). The retrospective, population-based cohort study included data from 118 hospitals in the Veterans Affairs health-care system.

Of 73,690 patients identified, 31,863 received azithromycin. These cases were matched with 31,863 patients who received another guideline-appropriate antibiotic.

All patients were aged 65 years and older, had been hospitalized for pneumonia between October 2001 and September 2012, and had received antibiotic therapy based on national clinical practice guidelines.

Treatment that included azithromycin was associated with a lower risk of death but a slightly increased risk of myocardial infarction compared with use of other antibiotics. Ninety-day mortality was significantly lower among persons who received azithromycin (17.4% vs. 22.3%)./p>

Although there was an increased risk of heart attack (5.1% vs. 4.4%), there was no significantly increased risk of any cardiac event (43.0% vs. 42.7%), heart failure (26.3% vs. 26.2%), or cardiac arrhythmia (25.8% vs. 26.0%).

As Mortensen observed in a statement from the Veterans Health Administration announcing the study results, the number needed to treat with azithromycin was 21 to prevent 1 death within 90 days, compared with a number needed to harm of 144 for myocardial infarction—corresponding to a net benefit of approximately 7 deaths averted for every 1 myocardial infarction induced.