Jockey Club School of Public Health and Primary Care, the Chinese University of Hong Kong, 999077, Hong Kong, China.
Xiangya School of Public Health, Central South University, Changsha 410006, Hunan Province, China.
J Integr Med. 2024 May;22(3):223-234. doi: 10.1016/j.joim.2024.04.003. Epub 2024 Apr 23.
Previously published meta-epidemiological studies focused on Western medicine have identified some trial characteristics that impact the treatment effect of randomized controlled trials (RCTs). Nevertheless, it remains unclear if similar associations exist in RCTs on Chinese herbal medicine (CHM). Further, Chinese medicine-related characteristics have not been explored yet.
To investigate trial characteristics related to treatment effect estimates on CHM RCTs.
This meta-epidemiological study searched 5 databases for systematic reviews on CHM treatment published between January 2011 and July 2021.
An eligible systematic review should only include RCTs of CHM and conduct at least one meta-analysis.
Two reviewers independently conducted data extraction on general characteristics of systematic reviews, meta-analyses and included RCTs. They also assessed the risk of bias of RCTs using the Cochrane risk of bias tool. A two-step approach was used for data analyses. The ratio of odds ratios (ROR) and difference in standardized mean differences (dSMD) with 95% confidence interval (CI) were applied to present the difference in effect estimates for binary and continuous outcomes, respectively.
Ninety-one systematic reviews, comprising 1338 RCTs were identified. For binary outcomes, RCTs incorporated with syndrome differentiation (ROR: 1.23; 95 % CI: [1.07, 1.39]), adopting Chinese medicine formula (ROR: 1.19; 95% CI: [1.03, 1.34]), with low risk of bias on incomplete outcome data (ROR: 1.29; 95% CI: [1.06, 1.52]) and selective outcome reporting (ROR: 1.12; 95% CI: [1.01, 1.24]), as well as a trial size ≥ 100 (ROR: 1.23; 95% CI: [1.04, 1.42]) preferred to show larger effect estimates. As for continuous outcomes, RCTs with Chinese medicine diagnostic criteria (dSMD: 0.23; 95% CI: [0.06, 0.41]), judged as high/unclear risk of bias on allocation concealment (dSMD: -0.70; 95% CI: [-0.99, -0.42]), with low risk of bias on incomplete outcome data (dSMD: 0.30; 95% CI: [0.18, 0.43]), conducted at a single center (dSMD: -0.33; 95% CI: [-0.61, -0.05]), not using intention-to-treat analysis (dSMD: -0.75; 95% CI: [-1.43, -0.07]), and without funding support (dSMD: -0.22; 95% CI: [-0.41, -0.02]) tended to show larger effect estimates.
This study provides empirical evidence for the development of a specific critical appraisal tool for risk of bias assessments on CHM RCTs. Please cite this article as: Wang BH, Lin YL, Gao YY, Song JL, Qin L, Li LQ, Liu WQ, Zhong CCW, Jiang MY, Mao C, Yang XB, Chung VCH, Wu IXY. Trial characteristics and treatment effect estimates in randomized controlled trials of Chinese herbal medicine: A meta-epidemiological study. J Integr Med. 2024; 22(3): 223-234.
之前发表的侧重于西药的荟萃分析研究已经确定了一些影响随机对照试验（RCT）治疗效果的试验特征。然而，中药（CHM）的 RCT 是否存在类似的关联尚不清楚。此外，与中医相关的特征尚未得到探索。
探讨与 CHM RCT 治疗效果估计相关的试验特征。
本荟萃分析研究检索了 2011 年 1 月至 2021 年 7 月发表的关于 CHM 治疗的系统评价，共 5 个数据库。
合格的系统评价应仅包括 CHM 的 RCT，并进行至少一项荟萃分析。
两名评审员独立对系统评价、荟萃分析和纳入 RCT 的一般特征进行了数据提取。他们还使用 Cochrane 偏倚风险工具评估了 RCT 的偏倚风险。采用两步法进行数据分析。比值比（ROR）和标准化均数差（dSMD）的差异及其 95%置信区间（CI）分别用于表示二分类和连续性结局的效应估计差异。
共确定了 91 项系统评价，包含 1338 项 RCT。对于二分类结局，纳入了辨证论治（ROR：1.23；95%CI：[1.07，1.39]）、采用中药方剂（ROR：1.19；95%CI：[1.03，1.34]）、低偏倚的 RCT（ROR：1.29；95%CI：[1.06，1.52]）和选择性结局报告（ROR：1.12；95%CI：[1.01，1.24]）以及试验规模≥100（ROR：1.23；95%CI：[1.04，1.42]）的 RCT 更倾向于显示更大的效果估计。对于连续性结局，采用中医诊断标准的 RCT（dSMD：0.23；95%CI：[0.06，0.41]）、被判断为分配隐藏高/不确定偏倚（dSMD：-0.70；95%CI：[-0.99，-0.42]）、低偏倚的 RCT（dSMD：0.30；95%CI：[0.18，0.43]）、单中心进行的 RCT（dSMD：-0.33；95%CI：[-0.61，-0.05]）、未采用意向治疗分析（dSMD：-0.75；95%CI：[-1.43，-0.07]）和无资金支持（dSMD：-0.22；95%CI：[-0.41，-0.02]）的 RCT 更倾向于显示更大的效果估计。
本研究为开发针对中药 RCT 偏倚风险评估的特定评价工具提供了经验证据。请引用本文为：Wang BH, Lin YL, Gao YY, Song JL, Qin L, Li LQ, Liu WQ, Zhong CCW, Jiang MY, Mao C, Yang XB, Chung VCH, Wu IXY. Trial characteristics and treatment effect estimates in randomized controlled trials of Chinese herbal medicine: A meta-epidemiological study. J Integr Med. 2024; 22(3): 223-234.
