title: Pharmaceutical industry sponsorship and research outcome and quality: systematic review.
abstract: OBJECTIVE
  To investigate whether funding of drug studies by the pharmaceutical industry is associated with outcomes that are favourable to the funder and whether the methods of trials funded by pharmaceutical companies differ from the methods in trials with other sources of support.
  
  
  METHODS
  Medline (January 1966 to December 2002) and Embase (January 1980 to December 2002) searches were supplemented with material identified in the references and in the authors' personal files. Data were independently abstracted by three of the authors and disagreements were resolved by consensus.
  
  
  RESULTS
  30 studies were included. Research funded by drug companies was less likely to be published than research funded by other sources. Studies sponsored by pharmaceutical companies were more likely to have outcomes favouring the sponsor than were studies with other sponsors (odds ratio 4.05; 95% confidence interval 2.98 to 5.51; 18 comparisons). None of the 13 studies that analysed methods reported that studies funded by industry was of poorer quality.
  
  
  CONCLUSIONS
  Systematic bias favours products which are made by the company funding the research. Explanations include the selection of an inappropriate comparator to the product being investigated and publication bias.
authors.affiliation: School of Health Policy and Management, York University, Toronto, ON, Canada M3J 1P3. joel.lexchin@utoronto.ca
authors.forename: Joel
authors.initials: J
authors.lastname: Lexchin
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Bero
authors.forename: Benjamin
authors.initials: B
authors.lastname: Djulbegovic
authors.forename: Otavio
authors.initials: O
authors.lastname: Clark
mesh_terms: D002986:Clinical Trials as Topic / Q000592:standards; D004345:Drug Industry / Q000191:economics* / Q000941:ethics / Q000592:standards; D005381:Financing, Organized; D011643:Publishing / Q000191:economics; D012106:Research / Q000592:standards*; D012109:Research Support as Topic