title: Use of proton pump inhibitors and H2 blockers and risk of pneumonia in older adults: a population-based case-control study.
abstract: OBJECTIVE
  To examine whether use of proton pump inhibitors (PPIs) and H2 blockers is associated with increased pneumonia risk.
  
  
  METHODS
  We conducted a population-based, nested case-control study within Group Health, an integrated healthcare delivery system. Among community-dwelling, immunocompetent adults aged 65-94, we identified presumptive cases of ambulatory and hospitalized community-acquired pneumonia in 2000-2003 from ICD-9 codes and validated them by medical record review (N = 1125). Controls were selected, matched to cases on age, sex, and calendar year (N = 2235). Current PPI or H2 blocker use was ascertained from computerized pharmacy records. Comorbid illnesses and other characteristics were ascertained by medical record review. Multivariable conditional logistic regression was used to examine the association between medication use and pneumonia risk. We conducted sensitivity analyses using only administrative and pharmacy data to assess how these results differed from our primary results.
  
  
  RESULTS
  The prevalence of PPI or H2 blocker use was 21% (241/1125) for pneumonia cases and 16% (350/2235) for controls (adjusted odds ratio [OR] 1.03, 95% CI 0.86-1.24, compared to nonuse). No increased risk was seen for recent initiation. The prevalence of PPI use was 12% (132/1125) for cases and 7% (160/2235) for controls (adjusted OR 1.13, 95% CI 0.88-1.44). Analyses using only administrative and pharmacy data yielded risk estimates farther from the null (adjusted OR 1.32, 95% CI 1.17-1.49, for current PPI use versus nonuse).
  
  
  CONCLUSIONS
  Use of PPIs and H2 blockers is not associated with increased pneumonia risk in older adults. The increased risk observed in some prior studies may reflect confounding.
authors.affiliation: Group Health Research Institute, Seattle, Washington 98101-1448, USA. dublin.s@ghc.org
authors.forename: Sascha
authors.initials: S
authors.lastname: Dublin
authors.forename: Rod L
authors.initials: RL
authors.lastname: Walker
authors.forename: Michael L
authors.initials: ML
authors.lastname: Jackson
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Nelson
authors.forename: Noel S
authors.initials: NS
authors.lastname: Weiss
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Jackson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000897:Anti-Ulcer Agents / Q000009:adverse effects / Q000627:therapeutic use; D016022:Case-Control Studies; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006635:Histamine H2 Antagonists / Q000009:adverse effects* / Q000627:therapeutic use; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D011014:Pneumonia / Q000188:drug therapy / Q000453:epidemiology*; D011336:Probability; D054328:Proton Pump Inhibitors / Q000009:adverse effects* / Q000627:therapeutic use; D012307:Risk Factors
chemical_list: D000897:Anti-Ulcer Agents; D006635:Histamine H2 Antagonists; D054328:Proton Pump Inhibitors