MedDRA Adoption and Adverse Event Reporting Quality in Gastrointestinal and Abdominal Surgery Randomized Controlled Trials: A Cross-Sectional Analysis

IntroductionAdverse event (AE) reporting transparency is essential for evidence-based surgical practice, yet substantial reporting gaps persist despite Consolidated Standards for Reporting Trials (CONSORT) Harms guidance. The Medical Dictionary for Regulatory Activities (MedDRA) provides standardized terminology for AE classification, but its association with AE reporting quality remains unexplored. ObjectivesThe purpose of this study was to establish the frequency of Medical Dictionary for Regulatory Activities (MedDRA) utilization in gastrointestinal and abdominal surgical trials, identify predictors of its adoption, and quantify the association between MedDRA use and adverse event reporting quality as measured by Completeness scores, registry-publication Concordance, and overall Transparency indices. DesignCross sectional analysis of matched randomized controlled trial registry-publication pairs. Participants116 gastrointestinal and abdominal surgery randomized controlled trials registered on ClinicalTrials.gov with results posted between September 2009 and December 2024 and an associated peer-reviewed publication. Primary and Secondary Outcome MeasuresPrimary outcomes were differences in AE reporting quality between MedDRA-documenting and non-documenting trials, measured using Harms Reporting Completeness score (0-8), Concordance score (0-7), and Harms Transparency Index (0-15). Secondary outcomes included prevalence of MedDRA adoption and predictors of MedDRA documentation via univariable logistic regression. ResultsAmong 116 included trials, only 22 (18.8%) explicitly documented MedDRA use. Industry-funded trials (OR=29.32, 95% CI=8.94-118.50, p<0.001) and those with at least one U.S. site (OR=4.59, 95% CI=1.22-30.02, p=0.050) demonstrated significantly higher rates of MedDRA adoption. Trials documenting MedDRA use demonstrated significantly improved reporting across all three score parameters: Completeness score (p<0.001), Concordance score (p=0.002), and Transparency Index (p<0.001). MedDRA use was also associated with lower rates of registry-publication discordance across key safety metrics: serious adverse event (SAE) participant count registry-publication discordance was 59.1% in MedDRA documenting trials and 85.1% in non-MedDRA trials; mortality reporting discordance was 60.0% in MedDRA trials and 82.1% in non-MedDRA trials. ConclusionDespite strong association with improved AE reporting completeness and registry-publication concordance, MedDRA adoption in gastrointestinal and abdominal surgical trials remains below 20%, concentrated among industry-funded studies. The predominance of unstandardized terminology and free-text strategies promotes reporting inadequacies that complicate evidence synthesis and undermine evidence-based surgical practice. Journals, funding agencies, academic institutions, and researchers should prioritize the adoption of standardized AE terminology to enhance transparency and improve surgical research. Trial RegistrationPROSPERO CRD420251081191. Strengths and Limitations of this StudyO_LIThis is the first study to quantify the association between MedDRA use and adverse event reporting quality in surgical trials C_LIO_LIDual independent screening and extraction with pre-registered protocol minimizes bias and enhances reproducibility C_LIO_LIAnalysis limited to gastrointestinal and abdominal surgery; generalizability to other surgical subspecialties remains uncertain C_LIO_LIRequired explicit MedDRA documentation; trials using MedDRA without disclosure would be misclassified as non-users C_LIO_LIConcordance assessment examined numerical agreement without evaluating clinical significance of discrepancies C_LI