Risk of bias among 2,060 Chinese language randomized controlled trials on Chinese herbal medicine included in meta-analyses published in 2021-22: A cross-sectional study

The reliability of meta-analyses on Chinese herbal medicine (CHM) largely depends on the methodological quality of the included randomized controlled trials (RCTs). This study assessed the risk of bias (RoB) among Chinese-language CHM RCTs embedded in meta-analyses (MAs) published between 2021 and 2022. Chinese language CHM MAs were identified through literature searches across seven databases (three international and four Chinese databases). RCTs were extracted from the eligible MAs and their methodological quality was appraised using the Cochrane Risk of Bias (RoB) tool. Logistic regression analyses were conducted to explore associations between bibliographical characteristics and quality. Of 2,060 RCTs (published between 1997-2021), 93.01% (n=1,916) had low RoB in incomplete data, but only 43.90% (n=906) in random sequence generation. No RCTs had low RoB in selective outcome reporting. Non-patent CHM RCTs performed poorly in sequence generation, allocation concealment, and outcome assessment blinding but well in incomplete data. Government-funded RCTs showed better performance in sequence generation and outcome assessment but worse in incomplete data. No analysis was done for selective reporting due to lack of low RoB RCTs. The methodological quality of Chinese language RCTs embedded in recently published MAs was found to be unsatisfactory, indicating their limited utility in informing clinical decision. There is an urgent need for enhancing clinical trial training for researchers, reviewers, and editors in China.