New Users of Herbal Medicine Containing Aristolochic Acids and the Risk of Dementia in the Elderly: A Nationwide, Population-Based Study in Taiwan

BACKGROUND: Herbal medicine containing aristolochic acids (HMCAA) was used for inflammatory and infectious diseases. This study aimed to investigate the association between the usage of HMCAA and the risk of dementia. METHODS: A total of 199 new users of HMCAA were enrolled, along with 597 controls without the usage of HMCAA, at a ratio of 1:3 – matched by age, sex, and comorbidity, between 2000 and 2003 – from the National Health Research Institutes Database (NHRID) of Taiwan, which contains two million randomly sampled subjects, in this cohort study. We used Fine and Gray’s survival analysis (competing with mortality) to compare the risk of developing dementia during a 15-year follow-up period (2000–2015). RESULTS: In general, HMCAA was not significantly associated with dementia (adjusted subdistribution hazard ratio [SHR] = 0.861, 95% confidence interval [CI] = 0.484–1.532, p = 0.611) for the HMCAA-cohort, although differential risk was observed among the groups at risk. The patients with usage of HMCAA aged ≧ 85 years were associated with a higher risk in dementia (adjusted SHR: 6.243, 95% CI=1.258–21.084, p = 0.001), in comparison to those aged 50–54 years. Furthermore, the patients with usage of HMCAA that had cerebrovascular accidents were associated with an increased risk of dementia. CONCLUSION: The usage of HMCAA was associated with the risk of developing dementia in the patients aged ≧ 85 years.