Funding sources are under-reported in randomised clinical trials of biological treatments in sports medicine: a systematic review

Importance There have been numerous publications involving the use of biologics in sports medicine injuries. However, a lack of clarity exists with reporting industry affiliations and sources of funding. Objective The purposes of this study were (1) to determine the frequency of reporting of funding sources in randomised clinical trials evaluating the clinical effects of biological treatments in sports medicine and (2) to evaluate potential relationships between reported clinical results and affiliated funding sources. We hypothesised that funding sources would be under-reported and the favourability of the results would be associated with the specific type of funding received. Evidence review A systematic search of MEDLINE and Embase databases was performed to identify funding sources and favourability of conclusions reported for all randomised clinical trials that compared a biological treatment to a standard treatment for sports medicine-related injuries. Industry affiliation was defined as a funding source or author affiliation with the company that provided the biological product being studied. Extracted data included the reported purpose, conclusion, funding sources, researcher industry affiliations, sample size, minimum follow-up (FU) and the outcome metrics used. Two-tailed t-tests and logistic regression analyses were performed for analysis. Findings Ninety-eight studies met our inclusion criteria and included a total of 5898 subjects with a minimum FU of 6 weeks–24 months. These studies investigated shoulder, knee, foot and ankle, and elbow issues. Forty-eight of the 98 studies (49%) did not report the source of study funding. In total, 47 of the 98 studies (48%) reported favourable results, and 5 of these studies (10.6%) reported industry affiliations. Published studies with unknown funding sources reported conclusions in favour of the biological treatment significantly more often than those with reported funding sources (p=0.015). Conclusions and relevance Nearly half of the included studies did not disclose funding sources, and studies with unknown funding sources more frequently reported results in favour of the biological treatment. Clinical reports of randomised trials should emphasise reporting of funding sources to ensure data transparency and interpretability of results. Future initiatives should focus on developing standard international criteria for reporting research funding in scientific publications. Level of evidence II