Combined Traditional Chinese and Western Medicine Reduces Dementia Risk in Insomnia Patients: A Real-World Cohort Study

Background Benzodiazepines (BZDs) and Z-drugs are widely prescribed for insomnia, but have been linked to potential cognitive decline, with conflicting evidence regarding their association with dementia risk, particularly in aging populations. In Taiwan, Traditional Chinese Medicine (TCM) is commonly used as a complementary therapy for insomnia and has demonstrated benefits in slowing cognitive decline. However, the impact of combining TCM with Western pharmacotherapy on dementia risk remains unclear. Aims & Objectives This study aimed to evaluate whether the adjunctive use of TCM alongside BZDs and Z-drugs reduces the risk of dementia in patients with insomnia compared to the use of BZDs and Z-drugs alone. Method This retrospective cohort study was conducted using data from the Taiwan National Health Insurance Research Database (NHIRD). This study included 941, 267 patients aged > 45 years who were newly diagnosed with insomnia between 2002 and 2006. Patients were followed from the index date until the diagnosis of dementia, death, or December 31, 2022. To minimize confounding, inverse probability of treatment weighting (IPTW) based on propensity scores was applied. Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI), adjusting for demographic and clinical variables associated with dementia risk. Results During the follow-up period, 29% of patients were diagnosed with dementia. Compared to non-users, patients receiving combined TCM and Western medicine exhibited a significantly lower risk of dementia (adjusted HR: 0.41, 95% CI: 0.38–0.42), followed by those using Western medicine alone (adjusted HR: 0.63, 95% CI: 0.62–0.64) and those using TCM alone (adjusted HR: 0.70, 95% CI: 0.69–0.71). Subgroup analyses based on the type of hypnotic agent consistently revealed that the risk of dementia was lower among patients using both TCM and Western medicine—whether in combinations of BZDs plus TCM, Z-drugs plus TCM, or BZDs plus Z-drugs plus TCM—compared to those receiving either treatment modality independently. Notably, patients concurrently treated with TCM and benzodiazepines demonstrated the lowest dementia risk, with an HR of 0.44 (95% CI: 0.43–0.45). Discussion & Conclusions This large-scale, real-world cohort study suggests that both TCM and Western pharmacotherapy independently reduce dementia risk in patients with insomnia, with the combined use of TCM and Western medicine offering the most significant protective effects. Importantly, the adjunctive use of TCM did not increase the dementia risk, supporting its potential as a complementary strategy in clinical practice. Future research should focus on elucidating the pharmacological mechanisms underlying this integrative approach and its long-term cognitive benefits.