Association Between the Diabetes Drug Cost and Cardiovascular Events for Type 2 Diabetes in Korea: A National Health Insurance Service Database Analysis

Background: We aimed to investigate the long-term effects of diabetes drug costs on cardiovascular (CV) events and death. Methods: This retrospective observational study used the 2009–2018 National Health Insurance data in Korea. Among patients with type 2 diabetes, those who were taking antidiabetic drugs and did not have CV events before 2009 were included. Data on the annual cost of each diabetes drug were collected. The 10-year incidence of CV events (cardiac death, non-fatal myocardial infarction, stroke, hospitalization for heart failure, and coronary revascularization) and CV death were analyzed according to the diabetes drug cost quartiles (Q1 [the lowest] – Q4 [the highest]).Results: A total of 441,914 participants were enrolled (median age, 60 years; male, 57%). CV events and death occurred in 28.1% and 8.36% of patients, respectively. The overall diabetes drug cost was USD 271/year per person (range: 1–18,921). The 10-year incidence of CV events and death was lowest in Q3 and high in Q4 and Q1. After adjusting for CV risk factors, the risk of CV events increased in the sequential order of cost quartiles (hazard ratio (HR)=1 [ref], 1.102 [95% confidence interval (CI): 1.084–1.120], 1.137 [95% CI: 1.118–1.156], and 1.323 [95% CI: 1.3011.346]). The risk of CV death showed U-shaped pattern which was lowest in the Q3 (HR=0.943, 95% CI 0.903-0.984) and highest in the Q4 (HR= 1.234, 95% CI 1.182-1.287).Conclusion: The expenditure for diabetes drug affects 10-year CV events and death. Affording an appropriate diabetes cost at a similar CV risk is an independent protective factor for CV death.Trial registration: retrospectively registered