New study concludes risk of pneumonia increases with H2 and PPI therapies

A study released by the Canadian Medical Association Journal reported that the use of acid-suppressive drugs could be linked to an increased risk of pneumonia. According to this study, acid-suppressive drugs such as histamine2 receptor antagonists and proton pump inhibitors (PPIs) can increase gastric pH and allow bacterial colonization, which may increase the risk of respiratory tract infections.

Investigators Chun-Sick Eom, MD, MPH; Christie Y. Jeon, ScD; Ju-Won Lim, MD; and colleagues state that the observational and randomized controlled trials have so far yielded inconsistent findings about the connection between pneumonia and acid-suppressive drugs. The authors conducted a meta-analysis and systematic review of the literature from MEDLINE, Embase, and the Cochran Central Register for Controlled Trials to summarize this association.

In a review of 2,377 articles, the authors found a total of 31 studies published between 1985 and 2009 that met criteria for their study. These included 5 case-control, 3 cohort, and 23 randomized controlled trials. The authors included studies that specifically “investigated the association between use of acid-suppressive drugs and risk of pneumonia; quantified the outcome with adjusted odds ratios (ORs), relative risk, or number of events, and corresponding 95% confidence intervals (CIs); and reported the results for proton pump inhibitors and histamine2 receptor antagonists separately.”

A meta-analysis of the 8 observational studies found that “the overall risk of pneumonia was higher among people using proton pump inhibitors,” and that among patients in the randomized controlled trials, the use of H2-receptor antagonists “was associated with an elevated risk of hospital-acquired pneumonia.”

The study results found that for every 1,000 patients receiving acid-suppression drugs, 24 to 25 cases of pneumonia can be expected. This “translates to about 1 case of pneumonia for every 200 inpatients treated with acid-suppressive drugs.” The authors said that as 40% to70% of hospital-admitted patients receive these drugs, a considerable “burden of morbidity and mortality of hospital-acquired pneumonia may be attributable to this type of therapy.”

Public health implications for both hospital- and community-acquired pneumonia should prompt caution, and the investigators conclude that physicians should evaluate the risk for their patients when prescribing these drugs, “especially for patients who are already at risk for pneumonia.”