Abstract WMP48: The Credibility Of Subgroup Analyses Reporting In Stroke Trials Is Poor: A Methodological Review.

Abstract

Background: Subgroup analyses are widely used to evaluate heterogeneity of treatment effects in randomized clinical trials. However, there is a limited investigation of the quality of prespecified and reported subgroup analyses in stroke trials. This study evaluated the credibility of subgroup analyses in stroke trials. Methods and Analysis: We searched Medline/PubMed, Embase, the Cochrane Central Register of Controlled Trials, and the Web of Science from inception to March 24 th , 2021. Three reviewers screened, extracted, and analyzed the data from the publications. Primary publications of stroke trials that reported at least one subgroup effect and had published corresponding study protocols were included. The Instrument for Assessing the Credibility of Effect Modification Analyses (ICEMAN) was used to examine the quality of the subgroup effects reported. The risk of bias was assessed using the Cochrane Risk-of-Bias tool for randomized trials version 2. Results: Seventy-four articles met the inclusion criteria and altogether reported 647 subgroup effects. The median sample size was 1264 (interquartile range (IQR): 380 - 3876) while the median number of subgroups prespecified in the protocol was 6 (IQR:2 - 10), and 61 studies (82.4%) used the univariate test of interaction. One hundred and thirty-nine subgroup effects (43.6%) in acute stroke treatment and 131 subgroup effects (35.03%) in studies published in 2015 or later had moderate credibility. Overall, 458 subgroup effects (70.8%) had low credibility, while 189 subgroup effects (29.2%) had moderate credibility. Conclusion: Subgroup analysis reporting quality in stroke trials remains poor. Trialists and medical journal publishers must ensure that reporting guidelines, such as ICEMAN, are adopted to improve the credibility of reported subgroup analyses in stroke trials.