Commercially Funded and United States-Based Research Is More Likely to Be Published; Good-Quality Studies with Negative Outcomes Are Not

BACKGROUND: Prior studies implying associations between receipt of commercial funding and positive (significant and/or pro-industry) research outcomes have analyzed only published papers, which is an insufficiently robust approach for assessing publication bias. In this study, we tested the following hypotheses regarding orthopaedic manuscripts submitted for review: (1) nonscientific variables, including receipt of commercial funding, affect the likelihood that a peer-reviewed submission will conclude with a report of a positive study outcome, and (2) positive outcomes and other, nonscientific variables are associated with acceptance for publication. METHODS: All manuscripts about hip or knee arthroplasty that were submitted to The Journal of Bone and Joint Surgery, American Volume, over seventeen months were evaluated to determine the study design, quality, and outcome. Analyses were carried out to identify associations between scientific factors (sample size, study quality, and level of evidence) and study outcome as well as between non-scientific factors (funding source and country of origin) and study outcome. Analyses were also performed to determine whether outcome, scientific factors, or nonscientific variables were associated with acceptance for publication. RESULTS: Two hundred and nine manuscripts were reviewed. Commercial funding was not found to be associated with a positive study outcome (p = 0.668). Studies with a positive outcome were no more likely to be published than were those with a negative outcome (p = 0.410). Studies with a negative outcome were of higher quality (p = 0.003) and included larger sample sizes (p = 0.05). Commercially funded (p = 0.027) and United States-based (p = 0.020) studies were more likely to be published, even though those studies were not associated with higher quality, larger sample sizes, or lower levels of evidence (p = 0.24 to 0.79). CONCLUSIONS: Commercially funded studies submitted for review were not more likely to conclude with a positive outcome than were nonfunded studies, and studies with a positive outcome were no more likely to be published than were studies with a negative outcome. These findings contradict those of most previous analyses of published (rather than submitted) research. Commercial funding and the country of origin predict publication following peer review beyond what would be expected on the basis of study quality. Studies with a negative outcome, although seemingly superior in quality, fared no better than studies with a positive outcome in the peer-review process; this may result in inflation of apparent treatment effects when the published literature is subjected to meta-analysis.