Background: A systematic review is an important evidence synthesis technique used to collate results from individual studies, such as treatments for proximal humerus fractures. Therefore it is necessary to minimize bias in systematic reviews, including financial COIs. Financial bias has been shown to result in unreliable assessments of credibility, which is why transparency with COI is essential for accurate assessments of research. Objective: The aim of this study was to characterize the influence of financial bias on the results and conclusions of systematic reviews of proximal humerus fracture treatments and to characterize the nature of disclosed and undisclosed COIs. 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 duplicate, masked fashion. Data from the final reviews were extracted in a triplicate manner. The data included: PubMed ID and/or DOI; journal; publication date; author names; affiliations; interventions; funding source; risk of bias assessment/statement; whether systematic review author(s) on any of the primary studies; the articles primary outcome; whether an overall pooled effect estimate was calculated; pooled effect estimate; type of pooled effect estimate/significance; the primary outcomes favorability of pooled effect estimate; and favorability of narrative results/conclusions. All authors of each systematic review were screened for non-disclosed COIs. Results: We found no relationship between authorial COI and the results and conclusions of the systematic reviews. 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. Conclusions: Findings from this study have limited generalizability due to our small sample size. More studies are needed to fully elucidate the effect of financial bias on the results and conclusions of systematic reviews.
