Although H2-receptor antagonists and proton pump inhibitors may be terrific for quieting the pain of acid reflux or stemming a nasty attack of dyspepsia, they might, according to a new study, produce an unfortunate unintended result: pneumonia.
Scientists in the Netherlands examined hospital records of more than 360,000 people taking acid-suppressive drugs, excluding those also on antibiotic therapy for the treatment of Helicobacter pylori infection, to determine whether the reduction in gastric pH and consequent increase in bacterial and viral colonization were associated with higher rates of community-acquired pneumonia (as opposed to nosocomial pneumonia).
Of the 345,224 control patients (those not taking acid-suppressive drugs during the study period), 5,366 (1.5%) acquired pneumonia or probable pneumonia. Of the 19,459 patients who used acid-suppressive drugs, 477 (2.4%) acquired pneumonia or probable pneumonia (185 while taking the drugs and 292 afterward).
Although all recent use of acid-suppressive drugs was associated with an elevated risk of pneumonia, after adjustments for patient characteristics in all patients with pneumonia, the greatest risk was seen in those taking proton pump inhibitors at the time pneumonia developed. The authors also noted a relationship between dose and response, which they say supports "a real biological effect."
Several conditions were associated with an elevated risk of pneumonia when acid-suppressive drugs were being used: lung cancer, chronic obstructive pulmonary disease, concurrent immunosuppressive therapy, heart failure, and diabetes mellitus, among others.
The authors write that although the nationwide collection of patient data in a variety of settings makes the findings generalizable, the potential for misdiagnosis of subjects existed. To account for this, the authors examined the data again, excluding those for patients classified as having "probable" pneumonia, and the "detected association became stronger." Another limitation was that the database reflected only data on prescriptions written for acid-suppressive drugs, not on whether the prescriptions were filled or the drugs taken.
The authors conclude that although the risk of pneumonia increases with the use of acid-suppressive therapy, the risk is still low. But, they write, "patients with asthma or chronic obstructive lung disease, immunocompromised persons, children, and elderly persons should be treated with acid-suppressive drugs only when necessary and with the lowest possible dose."-Doug Brandt
Laheij RJF, et al. JAMA 2004;292(16): 1955-60.