The effects of Bu Yang Huan Wu Tang on post-stroke epilepsy: a nationwide matched study

Objective: To compare the long-term risk of epilepsy in stroke patients who use Bu Yang Huan Wu Tang (BYHWT) and those who do not. Methods:In the Taiwanese national insurance claims data, we identified newly diagnosed stroke patients receiving inpatient care in the years 2000-2004. Using propensity score-matched pairs to balance the baseline characteristics, we selected eligible stroke patients who did (n=8,971) and did not (n=8,971) receive BYHWT. These two groups were followed up until the end of 2009 to track the occurrence of epilepsy. We used Cox proportional hazard models to calculate the adjusted HRs and 95% CIs for post-stroke epilepsy during the follow-up period according to BYHWT use. Results: Compared with the control group, stroke patients with BYHWT had a reduced risk of epilepsy during the 5-9 years of the follow-up period (HR 0.69, 95% CI 0.61-0.77). The association between BYHWT and reduced post-stroke epilepsy was significant in various subgroups of stroke patients. There was a dose-dependent decrease in the frequency of epilepsy with increasing quantities of BYHWT use from 1 package (HR 0.77, 95% CI 0.66-0.90) to >= 6 packages (HR 0.52, 95% CI 0.42-0.65). Conclusion: Stroke patients who received BYHWT therapy had a reduced long-term risk of epilepsy, and the beneficial effect could be observed in various subgroups. However, future clinical trials will be necessary to corroborate the present findings and identify the biochemical mechanism involved.