title: Association Between Use of Proton Pump Inhibitors and a Clostridium difficile-Associated Disease Outbreak: Case-Control Study.
abstract: BACKGROUND
  The use of proton pump inhibitors (PPIs) has been implicated as a potential contributor to the development of Clostridium difficile-associated disease (CDAD) because of the ability of these drugs to substantially reduce the bactericidal effect of gastric acid. This study focused on the impact of PPIs, among other known risk factors, during an outbreak of CDAD in a hospital setting.
  
  
  OBJECTIVE
  The primary objective was to determine whether there was an association between current use of a PPI and the CDAD outbreak. Secondary objectives were to evaluate any correlations between the CDAD outbreak and past use of PPIs, use of antibiotics, diabetes mellitus, enteral feeding, cancer, gastrointestinal surgery, inflammatory bowel disease, and previous care or residence in an institutional setting.
  
  
  METHODS
  A retrospective case-control study was conducted. One hundred and fifty cases of hospital-acquired Clostridium difficile were identified. Patients were individually matched to controls for age, sex, date of admission to hospital, and hospital unit. The groups were compared with respect to each exposure.
  
  
  RESULTS
  Eight case patients could not be matched with suitable controls. Therefore, data from 142 cases and 142 controls were analyzed. There was no association between current use of a PPI and the CDAD outbreak (odds ratio [OR] 1.0, 95% confidence interval [CI] 0.99-1.01). Similarly, there was no correlation between the CDAD outbreak and diabetes, enteral feeding, cancer, gastrointestinal surgery, inflammatory bowel disease, or previous care or residence in an institution. However, the development of CDAD was positively associated with use of antibiotics within the 30 days preceding the infection (OR 12.0, 95% CI 4.0-35.7) and with past use of a PPI (OR 2.4, 95% CI 1.4-4.3).
  
  
  CONCLUSIONS
  The development of CDAD during a hospital outbreak was associated with use of antibiotics and with past, not current, use of PPIs.
authors.affiliation: , BScPhm, ACPR, was a Pharmacy Resident at Trillium Health Centre, Mississauga, Ontario, while completing this study. She is now a Pharmacist with Sudbury Regional Hospital, Sudbury, Ontario.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Linney
authors.forename: Tania
authors.initials: T
authors.lastname: Fernandes
authors.forename: Thomas
authors.initials: T
authors.lastname: Einarson
authors.forename: Anjana
authors.initials: A
authors.lastname: Sengar
authors.forename: John H
authors.initials: JH
authors.lastname: Walker
authors.forename: Allan
authors.initials: A
authors.lastname: Mills