title: Association of industry sponsorship and positive outcome in randomised controlled trials in general and abdominal surgery: protocol for a systematic review and empirical study.
abstract: BACKGROUND
  Industry sponsorship has been identified as a factor correlating with positive research findings in several fields of medical science. To date, the influence of industry sponsorship in general and abdominal surgery has not been fully studied. This protocol describes the rationale and planned conduct of a systematic review to determine the association between industry sponsorship and positive outcome in randomised controlled trials in general and abdominal surgery.
  
  
  METHODS
  A literature search in the Cochrane Library, MEDLINE and EMBASE and additional hand searches in relevant citations will be conducted. In order to cover all relevant areas of general and abdominal surgery, a new literature search strategy called multi-PICO search strategy (MPSS) has been developed. No language restriction will be applied. The search will be limited to publications between January 1985 and July 2014. Information on funding source, outcome, study characteristics and methodological quality will be extracted.The association between industry sponsorship and positive outcome will be tested by a chi-squared test. A multivariate logistic regression analysis will be performed to control for possible confounders, such as number of study centres, multinational trials, methodological quality, journal impact factor and sample size.
  
  
  CONCLUSIONS
  This study was designed to clarify whether industry-sponsored trials report more positive outcomes than non-industry trials. It will be the first study to evaluate this topic in general and abdominal surgery. The findings of this study will enable surgical societies, in particular, to give advice about cooperation with the industry and disclosure of funding source based on empirical evidence.
  
  
  BACKGROUND
  PROSPERO CRD42014010802.
authors.forename: Pascal
authors.initials: P
authors.lastname: Probst
authors.forename: Kathrin
authors.initials: K
authors.lastname: Grummich
authors.forename: Alexis
authors.initials: A
authors.lastname: Ulrich
authors.forename: Markus W
authors.initials: MW
authors.lastname: Büchler
authors.forename: Phillip
authors.initials: P
authors.lastname: Knebel
authors.affiliation: University Hospital Heidelberg, Department of General, Visceral and Transplantation Surgery, University of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany. markus.diener@med.uni-heidelberg.de.
authors.forename: Markus K
authors.initials: MK
authors.lastname: Diener
mesh_terms: D000005:Abdomen / Q000601:surgery*; D016265:Conflict of Interest; D013502:General Surgery; D006801:Humans; D007221:Industry / Q000191:economics*; D016032:Randomized Controlled Trials as Topic; D012109:Research Support as Topic; D000078202:Systematic Reviews as Topic; D016896:Treatment Outcome