The following is a summary of “Depression trial results: A cross-sectional study of ClinicalTrials.gov” published in the May 2023 issue of Psychiatric Research by Schmaling, et al.

Published clinical trials are a subset of the objective data required to evaluate depression treatments. In a systematic review (PROSPERO #CRD42020173606) of depression trial results registered on ClinicalTrials.gov, researchers assess the extent of selective and delayed reporting. Inclusion criteria included studies registered on ClinicalTrials.gov with depression as the condition, with 18-year-old or older participants, concluded between January 1, 2008, and May 1, 2019, and with results published by February 1, 2022. Cox regression analyses of the time to result posting from registration and the study’s conclusion included enrollment as a covariate. 

The median publication of results for 442 protocols occurred more than two years after study completion and five years after registration. Among protocols with incomplete results, the effect sizes (d or W) of 134 protocols were calculated. The median effect size for protocols with incomplete results was small (0.16, 95% CI: 0.08, 0.21). In 28% of protocols, observed effects were opposite to what was predicted. As pre-treatment data were inconsistent, between-group effect size calculations relied on post-treatment data. 

Compliance with the requirement that drug and device trials in the United States register with ClinicalTrials.gov is imperfect, and submissions need to be peer-reviewed. It is typical for depression treatment trials to elapse between the study’s conclusion and the results’ release. In addition, researchers frequently need to report the results of statistical tests. Failure to timely report trial results and omission of statistical test reporting may cause systematic literature reviews to overestimate treatment effects.

Source: sciencedirect.com/science/article/abs/pii/S0022395623001681