Meta-epidemiological study of publication integrity, and quality of conduct and reporting of randomized trials included in a systematic review of low back pain

Objective: To comprehensively describe the quality of conduct, reporting, and publication integrity characteristics for all trials included in a large Cochrane review, comparing those published by presumed predatory publishers with those published by nonpredatory publishers. Design: Cross-sectional meta-epidemiological study. Study selection: Two hundred seventy-nine studies (25,704 participants) eligible for the recent update of the “Exercise therapy for chronic low back pain” Cochrane review were included. Data extraction: Study and manuscript characteristics, including predatory publication status and other quality and integrity characteristics were extracted along with treatment effect. Results: Nine percent of trials included were in presumed predatory publications; 12% in the period since 2010. We found frequency of other concerning characteristics to range from low (eg, plagiarism, 5%) to common (eg, lack of evidence of trial registration or protocol publication [75%]; insufficient sample size [84%]) in included studies. Studies published by presumed predatory publishers consistently had inferior conduct, reporting and publication integrity characteristics. Presumed predatory publication was associated with missing conflict of interest statement (OR 7.6, 95% CI 3.0–19.1), inadequate follow-up duration (OR 11.2, 95% CI 3.7–33.7), incomplete study methods (OR 12.1, 95% CI 2.8–52.2) and baseline reporting (OR 4.3, 95% CI 1.6–11.7), and high risk of bias (OR 2.7, 95% CI 1.2–6.3). All (100%) presumed predatory publications were missing trial registrations (vs. 72%) and had inadequate sample sizes (vs. 82%). Trials published in presumed predatory journals did not appear to have inflated effect sizes. Conclusions: Predatory publishers pose a distinct challenge to the consumption and synthesis of randomized controlled trials. More work is needed in other clinical areas to understand the potential impact of randomized controlled trials published in predatory publications, and as a result, the potential impact on evidence from systematic reviews that include these studies.