LAUSR

OBJECTIVES Since 2011, the Korean government has implemented differential cost sharing to increase the utilization of primary care clinics for the management of chronic diseases. The objective of this study was to examine the impact of the prescription drug cost-sharing increase on outpatients' selection of the medical care institution. STUDY DESIGN This was a pre-post comparison study. METHODS Participants were 34,842 patients with hypertension and 13,886 patients with type 2 diabetes, who were all newly prescribed. Data were collected via national health insurance system claims. The change in the main medical care institution for disease management before and after the cost sharing policy was analyzed using logistic regression analysis. RESULTS Nearly 18% of participants with hypertension and 22% of participants with diabetes used tertiary care or general hospital outpatient services before the policy was implemented. After the increased prescription drug coinsurance rate (by 10-20%), the likelihood of selecting primary care clinics or small hospitals was significantly higher among patients with hypertension within 1 year (odds ratio [95% confidence interval] = 1.29 [1.19-1.41]) than before. However, the policy effect was not significant among patients with diabetes. CONCLUSIONS The cost sharing policy was effective in inducing patients with hypertension to manage their chronic disease in primary care institutions; however, this was not true for patients with diabetes. The assurance of high-quality disease management services and low out-of-pocket expenses may be needed to encourage patients with chronic diseases to use primary care clinics.