Has the National Health Insurance improved the inequality in the use of tertiary-care hospitals in Korea?

BackgroundTo improve financial protection against catastrophic illness, the Korean government expanded the benefit coverage of the National Health Insurance (NHI) for cancer patients in 2005. This paper examined whether the policy has reduced income-inequality in the use of tertiary care hospitals.MethodsWe evaluated the effect of the policy on income-inequalities in outpatient visits and inpatient admissions to tertiary care hospitals, based on triple difference estimators. Using nationwide claims data of the NHI from 2002 to 2010, we compared cancer patients as a treatment group with liver disease and cardio-cerebrovascular disease as control groups and the lower-income with the highest-income group.ResultsBefore the introduction of the policy, lower-income cancer patients utilized less inpatient and outpatient services in tertiary care hospitals than high-income patients did. After the benefit coverage was expanded, while the incidence and total number of inpatient admissions to tertiary care hospitals increased among cancer patients compared with liver diseases, lower-income cancer patients experienced a greater increase than those of higher-income did compared with both diseases. The use of outpatient services increased more in cancer patients than those of both diseases; however, the gap between the highest- and the lowest-income rarely decreased, except the incidence of visits when compared to liver disease.ConclusionOur findings indicated that the expanded NHI benefits coverage partially improved income-related inequalities in inpatient admissions to tertiary-care hospital, but not in outpatient visits.