Selective outcome reporting bias in randomized controlled trials on dental caries in children and adolescents: A meta-research study.

Introduction: Selective Outcome Reporting (SOR) is a type of bias that potentially manifests in Randomized Controlled Trials (RCTs) and is defined as the change or omission of the primary outcome in the publication compared to the protocol. Researchers may alter outcomes to emphasize statistical significant results. We aimed to assess the prevalence of SOR in RCTs related to dental caries in Pediatric Dentistry.

Methods: We conducted a search on the ClinicalTrials.gov and International Clinical Trials Registry Platform (ICTRP), using a comprehensive search strategy that included terms related to pediatric dentistry and dental caries, up to February 2023. Two independent reviewers included any trial that had two or more arms and focused on dental caries in pediatric dentistry. We excluded any registration that did not result in at least one published article. Data such as study characteristics and outcome data were extracted. The chi-square test was used with a significance level set at 5% to detect the association between SOR and the pre-specified variables.

Results: One hundred and forty-four protocols and their corresponding publications were included. SOR was observed in 58.9% (n=103), and 41.1% (n=72) having discrepancies in the primary outcome follow-up. Retrospectively registered studies accounted for 73.7%. SOR was significantly associated with discrepancies in the follow-up period (p<0.001) and with type of study design in paper (p=0.048).

Conclusion: The high prevalence of SOR in dental caries RCTs in pediatric dentistry confirms that the issue deserves attention. Achieving transparency in the process requires the implementation of an appropriate pre-registered protocol, disclosure of deviations from it, and allowing stakeholders to compare the established protocol with the submitted documents Registration DOI: https://doi.org/10.17605/OSF.IO/5UVJ8.