title: Proton pump inhibitors and risk of fracture: a systematic review and meta-analysis of observational studies.
abstract: OBJECTIVE
  Proton pump inhibitors (PPIs) are widely used in several acid-related gastrointestinal disorders. In vivo studies have suggested that gastric suppression by PPIs could result in decreased intestinal calcium absorption. Subsequently, there have been concerns that the chronic use of a PPI is associated with an increased risk of bone fracture. However, the results of clinical studies are conflicting.
  
  
  METHODS
  We performed a systematic review and meta-analysis of controlled observational studies to evaluate the risks of PPI use on fracture outcome. All controlled observational studies that compared fracture outcome in patients with PPI therapy with a control group were included. We calculated pooled odds ratios (ORs) using a random-effects model.
  
  
  RESULTS
  Of 1,668 identified studies, 10 (4 cohort and 6 case-control) with 223,210 fracture cases were included in our analysis. In PPI users, compared with non/past users, the OR for hip fracture (n=9) was 1.25 (95% confidence interval (CI)=1.14-1.37). The OR for vertebral fracture (n=4) was 1.50 (95% CI=1.32-1.72) and for wrist/forearm fracture (n=3) was 1.09 (95% CI=0.95-1.24). In subgroup analysis of hip fracture, this association was observed in both high-dose and low-dose PPI exposure. When stratified by duration of exposure, the short duration of PPI use was associated with increased risk of developing hip fracture (OR=1.24; 95% CI=1.19-1.28), whereas there was no significant increase in risk of hip fracture in long-term PPI users (OR=1.30; 95% CI=0.98-1.70). There was significant statistical and clinical heterogeneity among studies for the main analysis and most of the subgroup analyses.
  
  
  CONCLUSIONS
  Our results should be interpreted with caution. We found a modest association between PPI use and increased risk of hip and vertebral fractures, but no evidence of duration effect in subgroup analysis. However, observational studies cannot clarify whether the observed epidemiologic association is a causal effect or a result of unmeasured/residual confounding. Thus, randomized controlled studies are required to confirm or refute these results.
authors.affiliation: Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, Texas, USA. saowanee.ngamruengphong@ttuhsc.edu
authors.forename: Saowanee
authors.initials: S
authors.lastname: Ngamruengphong
authors.forename: Grigorios I
authors.initials: GI
authors.lastname: Leontiadis
authors.forename: Saba
authors.initials: S
authors.lastname: Radhi
authors.forename: Andrew
authors.initials: A
authors.lastname: Dentino
authors.forename: Kenneth
authors.initials: K
authors.lastname: Nugent
mesh_terms: D050723:Fractures, Bone / Q000139:chemically induced* / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D054328:Proton Pump Inhibitors / Q000009:adverse effects*
chemical_list: D054328:Proton Pump Inhibitors