اصلاحات بیمه بهداشت و رشد اقتصادی: تجزیه و تحلیل و شبیه سازی در ژاپن

This paper evaluates the drastic reforms of Japanese public health insurance initiated in 2006. We employ a computable general equilibrium framework to numerically examine the reforms for an aging Japan in the dynamic context of overlapping generations. Our simulation produced the following results: first, an increase in the co-payment rate, a prominent feature of the 2006 reform, would promote economic growth and welfare by encouraging private saving. Second, the ex-post moral hazard behavior following the increase in co-payment rates, however, reduces economic growth. Third, Japan's trend of increasing the future public health insurance benefits can mainly be explained by its aging population, and increasing the co-payment rate does little to reduce future payments of public health insurance benefits. Fourth, the effect on future economic burdens of reducing medical costs through efficiencies in public health insurance, emphasis on preventive medical care, or technological progress in the medical field is small. Finally, a policy of maintaining public health insurance at a fixed percentage of GDP will require reducing public health insurance benefits, perhaps up to 45% by 2050. Such a policy also reduces economic growth until approximately 2035. Our simulation indicates that the reform does not significantly reduce future public health insurance benefits, but it can enhance economic growth and welfare by encouraging private saving.

Japan has undergone one of the most drastic reforms of public health insurance since the present system was launched. Begun in 2006, several reforms have been implemented gradually and necessarily, because Japan's public health insurance program could be unsustainable as its population ages. Since medical expenditure by people 65 and older are more than half of Japan's total medical expenditure,1 the reform particularly aims at decreasing medical expenditure by the elderly. This study investigates the effect of the 2006 reform on economic growth of Japan by simulating scenarios involving an aging populace in a dynamic context of overlapping generations in a general equilibrium framework. Japan's current ratio of the national medical expenditure to GDP exceeds 8% and is growing faster than the economy. Their effect on GDP is no longer negligible, and trends imply that their effect on economic growth could increase in future. Detailed numerical examination of the reform's effects on growth is warranted. Another factor motivating reform is the prospect that future generations would pay higher premiums for public health insurance, if the current program is maintained. This study differs from previous studies in numerically exploring and evaluating intergenerational effects of reform through a multi-period overlapping-generations model developed by Auerbach and Kotlikoff (1983) within a general equilibrium framework.2 It has been empirically observed that changes in co-payments, a prominent feature of the 2006 reform, have little effect,3 and empirical studies using micro-data have found little evidence of ex-post moral hazard in individual behavior. However, the literature has evaluated the behavioral consequences of changing co-payment rates within a partial equilibrium framework and left unexplored the effects on the macro-economy and on the welfare of disparate generations. This study numerically examines, within a general equilibrium framework, the effect of changing the co-payment rate over time on the macro-economy and intergenerational welfare. The reform seeks to reduce national medical expenditure by improving efficiency in providing medical services and by urging practitioners to augment preventive care. As Hiroi (1994) pointed out, however, technological advances might induce increases in national medical expenditure. Thus, this study simulates the effects of increases and decreases in national medical expenditure via reform. Some advocate limiting the growth rate of Japan's national medical expenditure to the rate of economic growth. This argument is also evaluated numerically. Our simulation results indicate that the reform is not particularly effective in reducing future national medical expenditure. On the other hand, an increase in the co-payment rate would promote economic growth and welfare by encouraging private saving. However, the magnitude of the effect on economic growth is not large. The effect on future economic burdens of reducing medical costs through efficiencies in public health insurance, emphasis on preventive medical care, or technological progress in the medical field is also small. These results suggest that Japan's trend of increasing the future public health insurance benefits can mainly be explained by its aging population. This paper is organized as follows: the next section introduces the Japanese health care system. Section 3 explains reforms initiated in 2006. Section 4 simulates the effect on economic growth and burdens of changes in key instruments by incorporating population aging. Section 5 concludes.

The paper has investigated the effect of public health insurance reforms on Japan's economic growth and welfare, by simulating the reform for an aging Japan, in a dynamic computable general equilibrium framework. The paper has used actual and projected population data to capture realistic demographics, and the effects of the reform as well as recent policy arguments have been evaluated in a dynamic context. Our results are summarized as follows. First, increasing the co-payment rate, one of the most prominent changes in the reform, would improve economic growth and welfare by encouraging private saving. However, the magnitude of the effect on economic growth is not large—0.0% and 0.01% in year 2050 depending on the change in the co-payment rate, and 0.01–0.09% in the short-run. The positive effect on economic growth is relatively larger when the policy change is implemented, but the magnitude of the positive effect decreases over time. On the other hand, the positive effect of increasing the co-payment rate on lifetime income or welfare is greater among relatively younger generations. Our simulation model estimates that the increase in co-payment rate in the reform have induced benefits which vary between 10,000 yen for the generation born in 1920 and 3.52 million yen for the generation born in 2000. Second, potential ex-post moral hazard behavior also results in a decrease in medical expenditures, although it weakens the benefits to economic growth of increasing co-payment rates. The maximum short-run effect of the ex-post moral hazard on economic growth is measured at −0.04% when medical expenditures decrease by 10% because of the behavior. Third, the rise in future public health insurance benefits can mainly be explained by Japan's aging population, and increasing the co-payment rate does little to reduce future public health insurance benefits, even when re-examined in a general equilibrium framework. Fourth, reducing medical costs through efficiencies, preventive care, or technological progress has little effect on future economic burdens. A change in the national burden ratio in 2050 is merely 1.2% points even if per capita medical costs change by 10%. Finally, if government tries to hold public health insurance benefits as a percentage of GDP, it must continually reduce benefits, perhaps up to 45% by 2050. Such a policy also restrains economic growth until approximately 2035. Our simulation results indicate that the reform discussed in this paper is not particularly effective in reducing future national medical expenditure, and greater efficiencies and emphasis on preventive care do not significantly influence the macro-economy even if they reduce medical expenditures. Their miniscule macroeconomic effect suggests that future questions about the efficiency of the Japanese public health insurance and/or national medical expenditure should be examined in a microeconomic rather than macroeconomic context.