title: Value of Propensity Score Matching for Equalizing Comparator Groups in Observational Database Studies: A Case Study in Anti-infectives.
abstract: Propensity score methodologies can reduce bias and confounding in nonrandomized studies, including pharmaceutical comparative effectiveness studies. An observational case study was developed to demonstrate the impact of propensity score adjustments on outcomes (ie, discharge status) of patients hospitalized for complicated intra-abdominal infections.
  
  
  
  Two cohorts were examined: intensive care unit (ICU) (vs non-ICU) patients and tigecycline-treated patients (vs patients receiving other antibiotics). Discharge status was captured before propensity scoring.
  
  
  
  The impact of propensity scoring on discharge outcome was greater when comparing ICU patients versus non-ICU patients than when comparing tigecycline recipients versus nonrecipients.
  
  
  
  Propensity scoring should be examined carefully to optimize its effects. Moreover, propensity scoring only addresses bias and confounding in nonrandomized studies that are attributable to variables contained within the dataset (ie, so called "observables") and not to other variables that may influence the relationship between outcomes and other independent variables.
authors.affiliation: Pharmaceutical Health Services Research Department, University of Maryland School of Pharmacy, Baltimore, Maryland. Electronic address: dmullins@rx.umaryland.edu.
authors.forename: C Daniel
authors.initials: CD
authors.lastname: Mullins
authors.affiliation: Indegene Inc, Kennesaw, Georgia.
authors.forename: Frank R
authors.initials: FR
authors.lastname: Ernst
authors.affiliation: QuintilesIMS, New York, NY.
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Krukas
authors.affiliation: University of Cincinnati College of Medicine, Cincinnati, Ohio.
authors.forename: Joseph
authors.initials: J
authors.lastname: Solomkin
authors.affiliation: Department of General, Visceral and Thoracic Surgery, Klinkum Peine Academic Hospital of Medical University Hannover, Peine, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Eckmann
authors.affiliation: Medicine Development Group, Pfizer Inc, Collegeville, Pennsylvania; Columbia School of Public Health, New York, New York.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Shelbaya
authors.affiliation: Medicine Development Group, Pfizer Inc, Collegeville, Pennsylvania.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Quintana
authors.affiliation: Global Innovative Pharma Business, Pfizer Inc, New York, New York.
authors.forename: Arlene
authors.initials: A
authors.lastname: Reisman
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D003422:Critical Care; D016208:Databases, Factual / Q000706:statistics & numerical data*; D006801:Humans; D007362:Intensive Care Units; D016555:Matched-Pair Analysis; D008911:Minocycline / Q000031:analogs & derivatives / Q000627:therapeutic use; D064887:Observational Studies as Topic / Q000706:statistics & numerical data*; D057216:Propensity Score; D000078304:Tigecycline
chemical_list: D000900:Anti-Bacterial Agents; D000078304:Tigecycline; D008911:Minocycline
keywords: abdominal infection; glycylcycline; propensity score