Results of a Markov model analysis to assess the cost-effectiveness of statin therapy for the primary prevention of cardiovascular disease in Korea: the Korean Individual-Microsimulation Model for Cardiovascular Health Interventions.

BACKGROUND: Although hyperlipidemia is well recognized as a risk factor for cardiovascular disease (CVD), there has been no appraisal of the economic impact of statin therapy in Korea.

OBJECTIVE: The aim of this model analysis was to determine the cost-effectiveness of statin therapy versus no treatment for the primary prevention of CVD over a lifetime in Korea, from a health care system perspective.

METHODS: We developed the Korean Individual-Microsimulation Model for Cardiovascular Health Interventions (KIMCHI), an epidemiologic and economic Markov model of first-onset CVD in Korea in which all individuals began the simulation in the health state alive without CVD, and moved among the 4 health states (alive without CVD, alive with CVD, dead from CVD, and dead from non-CVD causes) in yearly cycles for any specified time horizon, up to 40 years. KIMCHI was populated with 372 subjects from the 2005 Korean National Health and Nutrition Examination Survey (KNHNES) who were aged > or =45 years, did not have a history of myocardial infarction or ischemic stroke, and met current Korean reimbursement criteria for treatment with lipid-lowering medications. The probability of first-onset CVD was estimated for each study participant individually, based on an Asian population-specific risk equation that relied on an individual's sex, age, serum total cholesterol, systolic blood pressure, current smoking status, diabetes mellitus status, and body mass index. Statin treatment was represented by a hybrid of atorvastatin and simvastatin (the most popular statins in Korea), the lipid-modifying effects of which were de rived from a published meta-analysis. Data regarding utilities and costs of CVD (both those covered and not covered by insurance) were derived from published local sources.

RESULTS: In the base case, the estimated incremental costutility ratio was 15,134,284 Korean won (KRW) per quality-adjusted life-year (QALY) gained, and the estimated incremental cost-effectiveness ratio was 20,657,829 KRW per life-year gained (LYG) (1200 KRW approximately US $1). Based on a willingness-to-pay (WTP) threshold of 30 million KRW per QALY saved, there was a 93.7% probability that statin therapy would be cost-effective. Given a WTP threshold of 20 million KRW per QALY, there was a 53.8% probability of being cost-effective. The probabilities at WTP thresholds of 30 and 20 million KRW per LYG were 62.4% and 25.8%, respectively.

CONCLUSIONS: Based on this analysis using data from the 2005 KNHNES and the KIMCHI model, statin therapy is likely to be cost-effective for the primary prevention of CVD among Koreans aged > or =45 years. The probability of being cost-effective was greater at a threshold of 30 million KRW per QALY (93.7%) than at 20 million KRW per QALY (53.8%).