Impact of differential copayment on patient healthcare choice: evidence from South Korean National Cohort Study

Abstract

<jats:sec><jats:title>Objective</jats:title><jats:p>We evaluate the effectiveness of mild disease differential copayment policy aimed at reducing unnecessary patient visits to secondary/tertiary healthcare institutions in South Korea.</jats:p></jats:sec><jats:sec><jats:title>Design</jats:title><jats:p>Retrospective study using difference-in-difference design.</jats:p></jats:sec><jats:sec><jats:title>Setting</jats:title><jats:p>Sample Research database provided by the Korean National Health Insurance Service, between 2010 and 2013.</jats:p></jats:sec><jats:sec><jats:title>Participants</jats:title><jats:p>206 947 patients who visited healthcare institutions to treat mild diseases during the sample period.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>A linear probability model with difference-in-difference approach was adopted to estimate the changes in patients’ healthcare choices associated with the differential copayment policy. The dependent variable was a binary variable denoting whether a patient visited primary healthcare or secondary/tertiary healthcare to treat her/his mild disease. Patients’ individual characteristics were controlled with a fixed effect.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>We observed significant decrease in the proportion of patients choosing secondary/tertiary healthcare over primary healthcare by 2.99 per cent point. The decrease associated with the policy was smaller by 14% in the low-income group compared with richer population, greater by 19% among the residents of Seoul metropolitan area than among people living elsewhere, and greater among frequent healthcare visitors by 33% than among people who less frequently visit healthcare.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>The mild disease differential copayment policy of South Korea was successful in discouraging unnecessary visits to secondary/tertiary healthcare institutions to treat mild diseases that can be treated well in primary healthcare.</jats:p></jats:sec>