Prevalence of financial conflicts of interest among systematic review authors regarding the management of proximal humerus fractures

Background: A systematic review is an important evidence synthesis technique used to collate results from individual studies, such as on treatments for proximal humerus fractures. Thus, a need exists for reliable and unbiased systematic reviews. The aim of this study was to characterize the influence of financial bias on the results and conclusions of systematic reviews and to characterize the nature of disclosed and undisclosed COIs of their authors.

Methods: Ovid MEDLINE and Ovid Embase databases were searched to locate systematic reviews covering proximal humerus fracture treatments. Following these searches, title and abstract screening was performed in a triplicate, masked fashion. Data from the final reviews comprising our sample were extracted in the same manner as screening. These data included several characteristics about the systematic reviews and about the authors, including: PubMed ID and/or DOI; journal name; publication date; name of authors; affiliations; compared treatment interventions; source of funding; full COI statement; risk of bias assessment; verbatim risk of bias statement; whether systematic review author(s) on any of the primary studies included in the review; number of self-cited primary studies; the articles primary outcome or the first outcome reviewed; whether an overall pooled effect estimate was calculated; pooled effect estimate for the primary outcome; type of calculated pooled effect estimate; significance of pooled effect estimate; the primary outcomes favorability of pooled effect estimate; and what was favored in the narrative results and conclusions. All authors of each systematic review were screened for non-disclosed COIs through a stepwise process which included 3 additional databases – the Open Payments database, Dollars for Profs, and the United States Patent and Trademark Office (USPTO). We evaluated for risk of bias using the Cochrane Collaboration’s criteria.

Results: We found no relationship between authorial COI and the results and conclusions of the systematic reviews; however, this finding is tempered by the small sample size of the included studies. Among the 17 included systematic reviews, 7 (41.2%) had at least one non-disclosed COI. Of the 7 reviews with a non-disclosed COI, 2 (28.6%) were found to have a high risk of bias. We were unable to assess for an association between industry funding and study outcomes and conclusions since no systematic reviews funded by industry were retrieved.

Conclusions: Findings from this study should be placed in light of our small sample size. Larger studies to elucidate the effect of financial bias on the results and conclusions of systematic reviews are clearly warranted.

Clinical Relevance: Financial bias has the potential to affect the outcomes and conclusions of systematic reviews. Patient care and clinical decision making are contingent upon well-designed, well-executed, and well-reported studies; thus, it is critical to understand the role of financial bias in systematic reviews.