title: Systematic review: Patterns of proton pump inhibitor use and adherence in gastroesophageal reflux disease.
abstract: OBJECTIVE
  Variation in how proton pump inhibitors (PPIs) are taken likely influences their clinical effectiveness, and must be considered when estimating PPI failure rates. This review aimed to systematically investigate the literature on patterns of PPI use in patients with gastroesophageal reflux disease (GERD).
  
  
  METHODS
  PubMed and Embase were searched (1989-May 2010) to identify observational studies providing information on patterns of PPI use in patients with GERD.
  
  
  RESULTS
  Of 902 studies identified, 13 met prespecified selection criteria. Across 2 database studies, 53.8%-67.7% of patients with GERD had a medication possession ratio (MPR) of >0.80. Across 2 more database studies, the mean MPR for the study population was 0.68 to 0.84. Across 3 surveys, 70%-84% of patients reported daily PPI use. In 2 surveys, the presence and severity of reflux symptoms increased PPI adherence, as did Barrett's esophagus in another 2 studies. Across 3 surveys, 11%-22.2% of patients reported twice daily PPI use, and across 6 studies 11.0%-44.8% of patients took GERD medication in addition to a PPI.
  
  
  CONCLUSIONS
  The results of this systematic review suggest that the majority of patients with GERD are relatively adherent to their PPI, although substantially different estimates were obtained using MPR data compared with surveys. Severe symptoms and the presence of Barrett's esophagus may increase PPI adherence, and other GERD medication is frequently taken in addition to a PPI. Limitations of studies in this area include inferring adherence from indirect MPR data, and recall bias associated with patient surveys.
authors.affiliation: School of Medicine and Health, Wolfson Research Institute, Durham University, Stockton-on-Tees, United Kingdom. a.p.s.hungin@durham.ac.uk
authors.forename: A Pali S
authors.initials: AP
authors.lastname: Hungin
authors.forename: Catherine
authors.initials: C
authors.lastname: Hill
authors.forename: Michael
authors.initials: M
authors.lastname: Molloy-Bland
authors.forename: Anan
authors.initials: A
authors.lastname: Raghunath
mesh_terms: D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D006801:Humans; D054328:Proton Pump Inhibitors / Q000627:therapeutic use*; D016896:Treatment Outcome; D016903:Drug Monitoring
chemical_list: D054328:Proton Pump Inhibitors