Comparative Effectiveness of Traditional Chinese Medicine vs. Losartan on Blood Pressure: Real-World Insights from RCT-Eligible Populations

When evaluating the effectiveness of a drug, a Randomized Controlled Trial (RCT) is often considered the gold standard due to its perfect randomization. While RCT assures strong internal validity, its restricted external validity poses challenges in extending treatment effects to the broader real-world population due to possible heterogeneity in covariates. In this study, we employed the augmented inverse probability of sampling weighted (AIPSW) estimator to generalize findings from an RCT comparing the efficacy of Songling Xuemaikang Capsule (SXC) —— a traditional Chinese medicine (TCM) and Losartan on hypertension reduction to a real-world trial-eligible population. Additionally, we conducted sensitivity analyses to assess the robustness of the AIPSW estimation against unmeasured confounders. The generalization results indicated that although SXC is less effective in lowering blood pressure than Losartan on week 2, week 4, and week 6, there is no statistically significant difference among the trial-eligible population at week 8, and the generalization is robust against potential unmeasured confounders. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial The study protocol was approved by the Institutional Review Board of Dongzhimen Hospital affiliated to Beijing University of Chinese Medicine (approval number: ECSL-BDY-2011-19) and was registered on the Chinese Clinical Trial Registry Platform ([www.chictr.org.cn][1]; Unique identifier: ChiCTRONC-11001612) ### Funding Statement This work was supported by the Beijing Nova Program of Science and Technology (Z211100002121061) and the Young Elite Scientist Sponsorship Program by the China Association for Science and Technology (2021-QNRC1-04). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Institutional Review Board of Dongzhimen Hospital affiliated to Beijing University of Chinese Medicine (approval number: ECSL-BDY-2011-19) I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The author cannot share the data without a permit from a relative institution. [1]: http://www.chictr.org.cn