Social burden of three major diseases in Japan: A time trend and future projections using the comprehensive cost of illness method

BACKGROUND: Three major diseases in Japan, cancer, heart disease, and cerebrovascular disease (CVD) are the leading causes of death in Japan. This study aimed to clarify the social burden of these diseases, including long-term care (LTC), and to predict future trends. METHODS: The comprehensive cost of illness (C-COI), a modification of the cost of illness (COI), was used to estimate the social burden of the three major diseases in Japan. The C-COI can macroscopically estimate both direct and indirect costs, including the LTC. A new method for future projections of the C-COI was developed according to the method for future projections of the COI. All data sources were government statistics. RESULTS: The C-COI of cancer, heart diseases, and CVD in 2017 amounted to 11.0 trillion JPY, 5.3 trillion JPY, and 6.5 trillion JPY, respectively. The projected future C-COI in 2029 was 10.3 trillion JPY, 5.3 trillion JPY, and 4.4 trillion JPY, respectively. In 2029, the LTC costs accounted for 4.4%, 12.8%, and 44.1% of the total C-COI, respectively. Informal care costs are projected to be approximately 1.7 times higher, assuming that all family caregivers will be replaced by professional caregivers in 2029. CONCLUSION: Indirect costs for all three diseases were projected to decrease owing to aging of the patient. In contrast to the other two diseases, the LTC cost of CVD accounted for a large proportion of the burden. The burden of CVD is expected to decrease in the future, but informal care by older family caregivers is suggested to reach its limits. In the future, the focus of resource allocation should shift from medical care to LTC, especially support for family caregivers. A method of future projections for the social burden based on the C-COI was considered effective for identifying issues for healthcare policy in the context of the times.