Clinical Question: Does use of acid-suppressive drugs increase the risk of community-acquired pneumonia (CAP)?

Setting: Population-based

Study Design: Case-control

Synopsis: The authors gathered data from a large general practice electronic patient record database of approximately 150 clinicians in the Netherlands. The database contained the complete medical records of approximately 500,000 patients and had been proven valid for pharmacoepidemiologic research. Patients with CAP were matched with 10 randomly selected control patients for sex, year of birth, and index date of enrollment to the database. Exposure to H₂-receptor antagonists and proton pump inhibitors (PPIs) also was classified by duration and extent of use of individual drugs.

The incidence rates of pneumonia in non–acid-suppressive drug users and acid-suppressive drug users were 0.6 and 2.45 per 100 person-years, respectively. Patients currently using PPIs were significantly more likely to develop pneumonia than those who stopped (number needed to treat to harm [NNH] per year = 449; 95 percent confidence interval [CI], 247 to 1,111). Similarly, current users of H₂-receptor antagonists also were significantly more likely to develop pneumonia (NNH per year = 635; 95 percent CI, 270 to 5,714). For current PPI users, the risk of pneumonia proportionally increased with increasing dosage.

Bottom Line: Current use of gastric acid-suppressive therapy, including H₂-receptor antagonists and PPIs, is associated with a small increased risk of CAP. Higher dosages of PPIs are associated with increasing risk. The absolute risk is very low and patients currently taking these medications can be controlled equally well with a reduced dosage or by stopping treatment altogether. (Level of Evidence: 3b)