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.