Quality Evaluation of Randomized Controlled Trials of Rhodiola Species: A Systematic Review

Background. Rhodiola is a worldwide used medicinal plant for its various medicinal functions, and the number of randomized controlled trials (RCTs) of Rhodiola is increasing in recent years. This study aims to evaluate the reporting quality and risk of bias of the current RCT reports of different Rhodiola species. Methods. Six databases including Embase, PubMed, Web of Science, the Cochrane Library, ClinicalTrial.gov, and China National Knowledge Infrastructure were searched to identify RCTs that used Rhodiola as a single intervention and were published in English or Chinese from inception to December 2020. The Consolidated Standards of Reporting Trials (CONSORT) 2010 statement was used as the checklist for assessment, and a scoring system was applied to the evaluation of RCTs. Score 0 represents no reporting or inadequate reporting, and score 1 represents adequate reporting. The risk of bias of the included studies was also assessed using the Cochrane Risk of Bias tool. Results. A total of 39 RCTs were included in this study, including 23 RCTs of Rhodiola rosea (R. rosea), 8 RCTs of Rhodiola crenulata (R. crenulata), and 8 RCTs of Rhodiola wallichiana (R. wallichiana). None of the included studies met all the CONSORT statement criteria, and the reporting quality of RCTs of the three Rhodiola species was all generally poor. Based on the risk of bias assessment, the majority of included studies were judged to have an unclear risk of bias in most domains due to inadequate reporting. Conclusions. There is inadequate reporting among the included RCTs of different Rhodiola species, and RCTs of Rhodiola with higher reporting quality and better methodological quality are needed.