OBJECTIVES: In Japan, in 2025, It is estimated that approximately 5 million elderly people will have Alzheimer’s disease (AD). Various disease-modifying treatments (DMTs) are being developed for AD targeting patients diagnosed with Mild Cognitive Impairment (MCI). The prescriptions are based on the accumulation of amyloid-β detected by PET scans, the cost of which is not covered by Universal Health Insurance (UHI) in Japan. This study aimed to determine the percentage of people with MCI who would be willing to pay for a PET scan, which costs about 500,000 JPY or 3300 EUR, as an out-of-pocket expense. The analysis results could help predict the cost of DMT.

METHODS: We asked the following survey question to 4,398 individuals from the general population: “Suppose you are 75 years old and have been diagnosed with MCI. If the diagnosis is confirmed by a PET scan, you would be eligible for the DMT covered by UHI to extend the period from MCI to the progression of AD by 2 years. Would you be willing to pay 500,000 JPY for the PET scan?" We performed several subgroup analyses.

RESULTS: Overall, 23.3% were willing to pay. Subgroup analyses showed that richer people or higher educated people tended to be willing to pay. Especially, 41.0%, 1.8 times of the average, of the people with the highest health literacy in the top 10% were positive. The simulation showed that post-launch DMT will cost around 780 billion yen after 4 years assuming the per-patient cost of 2 million JPY. If health literacy improves, the cost would rise to 1.4 trillion yen, which represents about 5% of Japan's National Health Expenditure.

CONCLUSIONS: About a quarter of people diagnosed with MCI could be willing to pay for PET scans to receive AD treatment. An improvement in health literacy could almost double the percentage.