상복부 초음파 검사 급여 확대에 따른 의료이용의 변화 : 이중차이(difference-in-difference) 혼합모형 추정방법을 이용하여

Abstract

Korea introduced the national health insurance system covering the entire population in a relatively short period of time after the implementation of the health insurance system. However, it has a policy burden of excessive household medical expenses. In order to solve these problems, the health insurance coverage expansion has been gradually introduced since 2005. However, there is little research that has evaluated the sustainability of the policy and its impacts after the policy expansion. In this study, we analyze the changes of medical utilization in tertiary care hospital due to expansion of upper abdominal ultrasound, which was introduced on April 1, 2018, as follow-up measures for the health insurance coverage expansion. And we will provide basic data for planning and promoting future policies. This study used the claims data held by the Health Insurance Review and Assessment Service, and the data is from July 1, 2017 to November 30, 2018. The study institutions include all 42 tertiary care hospital to minimize selection bias. Statistical analysis was performed using SAS version 9.4. The analysis method was a difference-in-difference mixed model analysis in which in the control group(other abdomen ultrasound group) for the upper abdomen ultrasound group is selected and the two groups compare and analyze for 8 months before and after introducing the policy. Model 1 included only DID related variables. Model 2 further included the number of beds as a facility factor, the number of ultrasonic devices as a equipment factor and the number of general doctors, the number of interns, the number of residents, the number of specialists, the number of nurses and the number of nurse assistants as personnel factors. Model 3 further includes ownership, total amount of medical care expenses and geographic region. The results showed the frequency of upper abdomen ultrasound increased statistically by 86% after expansion of upper abdominal ultrasound. In a equipment factor, the frequency of upper abdomen ultrasound was decreased in a group of 45-49 and a group of 50-66 compared with a group with 44 or fewer ultrasound devices. In personnel factors the frequency of upper abdomen ultrasound was statistically decreased when the number of general doctors, the number of interns, the number of nurse assistants, and the number of radiologists increased. In addition, the frequency of upper abdomen ultrasound of the other metro-cities and provinces were lower than that of Seoul. As a result of these researches, it can be seen that the policy for expanding the coverage by item serves as an incentive to increase the use of medical care. Financial considerations are needed when introducing the policy, and management of frequency of medical use is required through long-term monitoring. In addition, though subject is limited to those who have the disease or suspected of having the disease, the frequency of upper abdomen ultrasound increased. It can be seen that the unmet need is satisfied. This implies that the health insurance coverage expansion needs to be expanded from medical services for disease treatment to medical services for disease prevention. Based on the results of this study, it is expected that further research will be possible in the future.