Agreement in reporting between trial publications and current clinical trial registry in high impact journals: A methodological review

Objectives: The primary objective of this systematic survey was to examine the percentage of studies in which there was agreement in the reporting of the primary outcome between the currently updated version of the clinical trial registry and the published paper. We also investigated the factors associated with agreement in reporting of the primary outcome. Methods: We searched PubMed for all randomized control trials (RCT)s published in 2012-2015 in the top five general medicine journals (based on the 2014 impact factor). Two hundred abstracts (50 from each year) were randomly selected for data extraction. Agreement in reporting of 11 key study conduct items (e.g., sample size) and study characteristics (e.g., funding, number of sites) were extracted by two independent reviewers. Analysis: Descriptive analyses were conducted to determine the proportion of studies on which there was agreement in reporting of key study conduct items. Generalized estimating equations were used to explore factors associated with agreement in reporting of the primary outcome. Results: Of the 200 included studies, 87% had agreement in reporting of the primary outcome. After adjusting for other covariates, having greater than 50 sites was associated with an increased likelihood of agreement in reporting of the primary outcome (odds ratio = 7.1, 95% confidence interval = 1.39, 36.27, p = 0.018). Conclusions: We identified substantive disagreement in reporting between publications and current clinical trial registry, which were associated with several study characteristics. Further measures are needed to improve reporting given the potential threats to the quality and integrity of scientific research.