Laheij RJF, Sturkenboom MCJM, Hassing RJ, et al: Risk of community-acquired pneumonia and use of gastric acid-suppressive drugs. JAMA 2004;292(16):1955-60.
Gregor JC: Acid suppression and pneumonia: A clinical indication for rational prescribing. JAMA 2004;292(16):2012-3 (editorial).
Acid-suppressive drugs interfere with the ability of intragastric acidity to defend against ingested pathogens. The authors studied whether the use of acid-suppressive drugs was associated with community-acquired pneumonia. Over a 7-year period in the Netherlands, 5551 of 364,683 individuals developed first occurrences of pneumonia. The adjusted relative risk for pneumonia among persons currently using proton pump inhibitors (PPIs) was 1.89 (95% CI 1.36-2.62), and among current users of H2-receptor antagonists (H2RAs) was 1.63 (95% CI, 1.07-2.48). The authors reported a dose-response effect, with the risk of pneumonia lowest with H2RAs, greater with low-dose PPIs, and the greatest for those taking more than one daily dose of PPI. As in any retrospective study, these results could be misleading if some unknown but important difference existed originally between the groups. For example, the group with more pneumonia may have begun with more severe reflux that caused them to be unable to stop medication and also increased pneumonia risk. For most people who require acid-suppressive therapy, the higher risk for developing community-acquired pneumonia is not a problem because the absolute risk is so low. However, acid-suppressive drugs should be used only when necessary, and in the lowest possible dose, especially for children, elderly persons, and persons with asthma or immunocompromising disease.