Reporting characteristics of allergic rhinitis trials registered on ClinicalTrials.gov and in publications: an observational study

Background: Data from randomized controlled trials (RCTs) on Allergic rhinitis (AR) should be complete and consistent throughout multiple sources to ensure accurate evidence-based information. The aim of this study was to determine whether there are discrepancies in the reported data from AR trials. Methods: This cross-sectional study retrospectively analyzed completed RCTs on AR registered in ClinicalTrials.gov and last updated between 9/27/2009 and 10/4/2019 with results and corresponding publications. Completeness, informativeness and major changes to World Health Organization Trial Registration Data Set items as well as completeness of results data in ClinicalTrials.gov and corresponding publications were analyzed. Results: Omitted items were present in 35 (46.1%) of the 76 trials at initial registration, 15 (19.7%) at last registration, and in 22 (56.4%) of the 39 publications. All 76 trials between first and last registration and all 39 publications had major changes in registration items. Uninformative reporting of analyzed items were present both in ClinicalTrials.gov and publications. Completeness of results in ClinicalTrials.gov was satisfactory. In contrast, publications reported fewer adverse events. Conclusions: Discrepancies in data elements of AR trials are common both in ClinicalTrials.gov and subsequent publications. To ensure transparent data reporting from AR trials, multiple stakeholders should control the accuracy, consistency, and completeness of AR trial data to notice discrepancies before publication.