Publication of Randomized Clinical Trials in Pediatric Research: A Follow-up Study.

Importance: Nonpublication of research results in considerable research waste and compromises medical evidence and the safety of interventions in child health.

Objective: To replicate, compare, and contrast the findings of a study conducted 15 years ago to determine the impact of ethical, editorial, and legislative mandates to register and publish findings.

Design, Setting, and Participants: In this cohort study, abstracts accepted to the Pediatric Academic Societies (PAS) meetings from May 2008 to May 2011 were screened in duplicate to identify phase 3 randomized clinical trials enrolling pediatric populations. Subsequent publication was ascertained through a search of electronic databases in 2017. Study internal validity was measured using the Cochrane Risk of Bias Tool, the Jadad scale, and allocation concealment, and key variables (eg, trial design and study stage) were extracted. Associations between variables and publication status, time to publication, and publication bias were examined.

Main Outcomes and Measures: Publication rate, trial registration rate, study quality, and risk of bias.

Results: A total of 177 787 abstracts were indexed in the PAS database. Of these, 3132 were clinical trials, and 129 met eligibility criteria. Of these, 93 (72.1%; 95% CI, 53.8%-79.1%) were published. Compared with the previous analysis, the current analysis showed that fewer studies remained unpublished (183 of 447 [40.9%] vs 36 of 129 [27.9%], respectively; odds ratio [OR], 0.56; 95% CI, 0.36-0.86; P = .008). Fifty-one of 129 abstracts (39.5%) were never registered. Abstracts with larger sample sizes (OR, 1.92; 95% CI, 1.15-3.18; P = .01) and those registered in ClinicalTrials.gov (OR, 13.54; 95% CI, 4.78-38.46; P < .001) were more likely to be published. There were no differences in quality measures, risk of bias, or preference for positive results (OR, 1.60; 95% CI, 0.58-4.38; P = .34) between published and unpublished studies. Mean (SE) time to publication following study presentation was 26.48 (1.97) months and did not differ between studies with significant and nonsignificant findings (25.61 vs 26.86 months; P = .93). Asymmetric distribution in the funnel plot (Egger regression, -2.77; P = .04) suggests reduced but ongoing publication bias among published studies. Overall, we observed a reduction in publication bias and in preference for positive findings and an increase in study size and publication rates over time.

Conclusions and Relevance: These results suggest a promising trend toward a reduction in publication bias and nonpublication rates over time and positive impacts of trial registration. Further efforts are needed to ensure the entirety of evidence can be accessed when assessing treatment effectiveness.