title: Incidence of Campylobacter and Salmonella infections following first prescription for PPI: a cohort study using routine data.
abstract: OBJECTIVE
  To examine the incidence of Campylobacter and Salmonella infection in patients prescribed proton pump inhibitors (PPIs) compared with controls.
  
  
  METHODS
  Retrospective cohort study using anonymous general practitioner (GP) data. Anonymised individual-level records from the Secure Anonymised Information Linkage (SAIL) system between 1990 and 2010 in Wales were selected. Data were available from 1,913,925 individuals including 358,938 prescribed a PPI. The main outcome measures examined included incidence of Campylobacter or Salmonella infection following a prescription for PPI.
  
  
  RESULTS
  The rate of Campylobacter and Salmonella infections was already at 3.1-6.9 times that of non-PPI patients even before PPI prescription. The PPI group had an increased hazard rate of infection (after prescription for PPI) of 1.46 for Campylobacter and 1.2 for Salmonella, compared with baseline. However, the non-PPI patients also had an increased hazard ratio with time. In fact, the ratio of events in the PPI group compared with the non-PPI group using the prior event rate ratio was 1.17 (95% CI 0.74-1.61) for Campylobacter and 1.00 (0.5-1.5) for Salmonella.
  
  
  CONCLUSIONS
  People who go on to be prescribed PPIs have a greater underlying risk of gastrointestinal (GI) infection beforehand and they have a higher prevalence of risk factors before PPI prescription. The rate of diagnosis of infection is increasing with time regardless of PPI use, and there is no evidence that PPI is associated with an increase in diagnosed GI infection. It is likely that factors associated with the demographic profile of the patient are the main contributors to increased rate of GI infection for patients prescribed PPIs.
authors.affiliation: Swansea University, Swansea, UK. s.brophy@swansea.ac.uk
authors.forename: Sinead
authors.initials: S
authors.lastname: Brophy
authors.forename: Kerina H
authors.initials: KH
authors.lastname: Jones
authors.forename: Muhammad A
authors.initials: MA
authors.lastname: Rahman
authors.forename: Shang-Ming
authors.initials: SM
authors.lastname: Zhou
authors.forename: Ann
authors.initials: A
authors.lastname: John
authors.forename: Mark D
authors.initials: MD
authors.lastname: Atkinson
authors.forename: Nick
authors.initials: N
authors.lastname: Francis
authors.forename: Ronan A
authors.initials: RA
authors.lastname: Lyons
authors.forename: Frank
authors.initials: F
authors.lastname: Dunstan
mesh_terms: D000328:Adult; D000368:Aged; D002169:Campylobacter Infections / Q000453:epidemiology*; D016009:Chi-Square Distribution; D011307:Drug Prescriptions; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D054328:Proton Pump Inhibitors / Q000627:therapeutic use; D012189:Retrospective Studies; D012307:Risk Factors; D012480:Salmonella Infections / Q000453:epidemiology*; D013997:Time Factors; D014852:Wales / Q000453:epidemiology
chemical_list: D054328:Proton Pump Inhibitors