Gastric acid suppression is associated with increased risk of pneumonia

Question Does use of acid suppressing drugs increase the risk of community acquired pneumonia

Synopsis Acid suppressing drugs, including H receptor antagonists (H2RAs) and proton pump inhibitors (PPIs), may increase the risk of bacterial colonisation of the gastrointestinal tract by increasing gastric pH. There is some evidence that acid suppression increases the risk of nosocomial infections, but few studies have been done in the outpatient setting. For this case-control trial, the authors gathered data from a large electronic database of the patient records of about 150 general practitioners in the Netherlands. This database contains the complete medical records of approximately 500 000 patients and has been proved valid for pharmacoepidemiologic research. Patients with community acquired pneumonia were matched with 10 randomly selected control patients by sex, year of birth, and index date of enrolment to the database. Exposure to H2RAs and PPIs was classified by duration and amount of use of individual drugs. The incidence rates of pneumonia in non-acid suppressing drug users and acid suppressive drug users were 0.6/100 person years in patients who did not use acid suppressing drugs and 2.45/100 person years in those who did. Patients currently using PPIs were significantly more likely to develop pneumonia than those who stopped (number needed to treat to harm (NNTH) per year = 449; 95% confidence interval 247 to 1111). Similarly, current users of H2RAs were also significantly more likely to develop pneumonia (NNTH per year = 635; 270 to 5714). For current PPI users, the risk of pneumonia increased proportionally with increasing dosage.

Bottom line Current use of drugs that suppress gastric acid, including H receptor antagonists and proton pump inhibitors, is associated with a slightly increased risk of community acquired pneumonia. Higher doses of PPIs are associated with increasing risk. The risk is very low, and patients currently taking these drugs can be equally well controlled with a reduced dose or by stopping treatment altogether.

Level of evidence 3b (see www.infopoems.com/levels.html). Individual case-control study.

Laheij RJ, Sturkenboom MC, Hassing RJ, Dieleman J, Stricker BH, Jansen JB. Risk of community-acquired pneumonia and use of gastric acid-suppressive drugs. JAMA 2004;292: 1955-60.

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