Ethnopharmacological relevance: Previous studies had indicated that hormone therapy (HT) may increase the risk of ischemic stroke (IS) in menopausal women. However, little is known about the benefits and risks of use of Chinese herbal medicine (CHM) in conditions related to hormone use. The aim of this study is to explore the risk of IS in menopausal women treated with HT and CHM.
Materials and methods: A total of 32,441 menopausal women without surgical menopause aged 40-65 years were selected from 2003 to 2010 using the 2-million random samples of the National Health Insurance Research Database in Taiwan. According to the medication usage of HT and CHM, we divided the current and recent users into two groups: an HT use-only group (n = 4989) and an HT/CHM group (n = 9265). Propensity-score matching samples (4079 pairs) were further created to deal with confounding by indication. The adjusted hazard ratios (HR) of IS were estimated by the robust Cox proportional hazards model.
Results: The incidence rate of IS in the HT/CHM group was significantly lower than in the HT group (4.5 vs. 12.8 per 1000 person-year, p < 0.001). Multivariate analysis results indicated that additional CHM use had a lower risk of IS compared to the HT group (HR = 0.3; 95% confidence interval [CI], 0.21-0.43). Further subgroup analyses and sensitivity analyses had similar findings.
Conclusion: We found that combined use of HT and CHM was associated with a lower risk of IS. Further study is needed to examine possible mechanism underlying this association.
Keywords: Chinese herbal medicine; Hazard ratio; Hormone therapy; Ischemic stroke; Menopause; Pharmaco-epidemiology.
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