Transparency of results reporting for depression treatment studies in ClinicalTrials.gov: a cross-sectional study

Abstract

ObjectivesDepression affects an estimated 7% of the adult population at an estimated cost of over US$200 billion/year in the USA. Complete, transparent reporting of clinical trial data facilitates valid estimates of treatment efficacy. In the USA, ClinicalTrials.gov increases transparency through mandatory prospective trial registration and outcome reporting. We examined characteristics of the transparent reporting of depression treatment studies registered in ClinicalTrials.gov.DesignCross sectional.Setting and participantsUS-based studies identified in a search of ClinicalTrials.gov with depression as the condition, enrolling ages 18 and older, and completed between 1 January 2008 and 1 May 2019.InterventionsAll interventions were included.Main outcomes and measuresThe main outcome was whether any results were reported prior to 1 May 2020. Data were extracted regarding inclusion and exclusion criteria, publications related to the study and specification of hypotheses.Results725 studies involving 156 634 patients met inclusion criteria. 416 (57.4%) of the studies posted some results. However, statistical test results were not included in 230 studies (55.3%). Most studies had data that could have been analysed and reported. Compared with studies without results, studies with any results were more likely to have hypotheses, include drug treatment conditions, and to have publications related to the study.ConclusionsRequired study registration does not always result in transparent outcome reporting. Better compliance with mandated reporting and improved reporting standards would facilitate a more comprehensive representation of depression treatment research.