BACKGROUND: Over the last few decades medical research and development has come to depend more heavily on the financial support of industry. However, there is concern that financial relations between the medical community and medical industry could unduly influence medical research and therefore patient care. Our objective was to determine whether conflict of interest owing to authors'/investigators' financial affiliation with industry associated with their academic research has been identified in the surgical literature. In particular, we sought to answer the following questions: What is the extent of such conflict of interest? Does conflict of interest bias the results of academic surgical research in favour of industry? What are the potential causes of this proindustry bias? METHODS: We conducted a systematic review of the literature in May 2008 using the OVID SP search engine of MEDLINE, EMBASE, CINAHL, the Cochrane Database of Systematic Reviews, DARE and Health Technology Assessment. Quantitative studies that included a methods section and reported on conflict of interest as a result of industry funding in surgery-related research specifically were included in our analysis. RESULTS: The search identified 190 studies that met our criteria. Author/investigator conflict of interest owing to financial affiliation with industry associated with their academic research is well documented in the surgical literature. Six studies demonstrated that authors with such conflicts of interest were significantly more likely to report a positive outcome than authors without industry funding, which demonstrates a proindustry bias. Two studies found that the proindustry bias could not be explained by variations in study quality or sample size. CONCLUSION: The conflict of interest that exists when surgical research is sponsored by industry is a genuine concern.
