The baseline study population is all insured Koreans residing in Korean territories. These people are divided into three categories: NHI program for employee and self-employed groups and medical aid beneficiaries. The MA program is managed by the Korean government and is a public assistance scheme to secure the minimum livelihood of low-income households and to assist with self-help by providing medical services. As shown in Table 1 [12 ], 100% of the Korean population is covered by the Korean NHI system. In 2013, the NHI system covered 97.2% (n=49,989,620) of the population and the MA system covered the remaining and 2.8% (n=1,458,871) of the population.