title: High-dimensional versus conventional propensity scores in a comparative effectiveness study of coxibs and reduced upper gastrointestinal complications.
abstract: OBJECTIVE
  High-dimensional propensity score (hd-PS) adjustment has been proposed as a tool to improve control for confounding in pharmacoepidemiological studies using longitudinal claims databases. We investigated whether hd-PS matching improved confounding by indication in a study of Cox-2 inhibitors (coxibs) and traditional nonsteroidal anti-inflammatory drugs (tNSAIDs) and their association with the risk of upper gastrointestinal complications (UGIC).
  
  
  METHODS
  In a cohort study of new users of coxibs and tNSAIDs we compared the effectiveness of these drugs to reduce UGIC using hd-PS matching and conventional propensity score (PS) matching in the German Pharmacoepidemiological Research Database.
  
  
  RESULTS
  The unadjusted rate ratio (RR) of UGIC for coxib users versus tNSAID users was 1.21 [95 % confidence interval (CI) 0.91-1.61]. The conventional PS matched cohort based on 79 investigator-identified covariates resulted in a RR of 0.84 (0.56-1.26). The use of the hd-PS algorithm based on 900 empirical covariates further decreased the RR to 0.62 (0.43-0.91).
  
  
  CONCLUSIONS
  A comparison of hd-PS matching versus conventional PS matching resulted in improved point estimates for studying an intended treatment effect of coxibs versus tNSAIDs when benchmarked against results from randomized controlled trials.
authors: Department of Clinical Epidemiology, BIPS-Institute for Epidemiology and Prevention Research, Achterstr. 30, 28359 Bremen, Germany. garbe@bips.uni-bremen.de
authors: E
authors: E
authors: Garbe
authors: S
authors: S
authors: Kloss
authors: M
authors: M
authors: Suling
authors: I
authors: I
authors: Pigeot
authors: S
authors: S
authors: Schneeweiss
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000009:adverse effects*; D019985:Benchmarking; D057186:Comparative Effectiveness Research; D016001:Confidence Intervals; D015986:Confounding Factors, Epidemiologic; D052246:Cyclooxygenase 2 Inhibitors / Q000009:adverse effects*; D005260:Female; D005767:Gastrointestinal Diseases / Q000139:chemically induced / Q000453:epidemiology / Q000517:prevention & control*; D005858:Germany / Q000453:epidemiology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D017891:Pharmacoepidemiology / Q000379:methods*; D057216:Propensity Score; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D052246:Cyclooxygenase 2 Inhibitors