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.