Supplementary Material for: Impact of Traditional Korean Medicine Use on Medical Costs in Patients with Cancer in Korea

Introduction: Cancer remains a leading cause of death worldwide, and many patients use traditional medicine (TM) or complementary and alternative medicine (CAM) to manage symptoms; however, their economic impact remains unclear. In Korea, traditional Korean medicine (TKM) is practiced alongside Western medicine (WM); however, some CAM practices lie outside licensed TKM. This study investigated TKM use and its costs among cancer patients, examining its relationship with WM and CAM costs.
Methods: This study classified cancer patients from the 2016 Korean Health Panel Survey (KHPS) into treatment and comparison groups based on TKM use in 2017. Propensity score matching (PSM) was applied to ensure comparability, while WM and CAM costs in 2018 were analyzed using generalized linear models and marginal effects.
Results: After 1:2 PSM, 374 cancer patients were included (125 TKM users; 249 nonusers). TKM use was not significantly associated with WM costs; however, it was linked to reduced CAM costs. TKM costs showed no significant association with WM or CAM costs. Subgroup analysis revealed that TKM use was associated with a greater decrease in CAM costs among survivors diagnosed more than five years prior.
Conclusion: TKM use among cancer patients was associated with reduced CAM costs but not with WM costs. The CAM cost-saving effect was more substantial in long-term survivors, suggesting a shift toward institutionalized TKM use; however, increased TKM spending did not further reduce CAM costs. These findings imply a need for policies that promote evidence-based, appropriate TKM use to improve healthcare cost efficiency.