All governments confront the same harsh reality: with limited healthcare budgets, how do you choose which treatments to finance and which to deny? For many years, the response has been encapsulated in a single figure, representing the fixed cost for a year of optimal health. In Japan, this figure is approximately 5 million yen. Treatments that exceed this cost per healthy year gained are generally turned down, while those that are less expensive are approved.
Researchers from Tokyo University of Science contend that this methodology has a critical flaw. The economic significance of a year of good health at age 25 is not equivalent to that of a year at age 85, and disregarding this discrepancy subtly skews the allocation of medical resources among an aging populace.
In a study published in Scientific Reports, a team directed by Professor Ryuta Takashima developed a model that adjusts the valuation of a quality-adjusted life year (the QALY) based on an individual’s age and realistic health trajectories. They assessed how this value fluctuates across various life stages by employing Japanese wage statistics, consumption habits, and survival probabilities.
This pattern contradicts common sense. The financial value of a QALY tends to increase with age. For individuals in their 20s, an additional healthy year may be valued at 3 to 4 million yen, while for those in their 80s, that same year could surpass 9 million yen. This variation arises partly due to discounting (where future benefits are deemed less valuable than immediate ones) but also because older individuals experience the advantages of a longer life expectancy more tangibly.
Four Paths Through Aging
To ground their estimates in reality, the researchers simulated how life quality usually evolves throughout a person’s lifetime. One scenario assumes a slow, gradual decline beginning at age 50. Another predicts a dramatic health downturn at 60, possibly due to chronic ailments, followed by a period of stabilization. A third scenario depicts a slow decline throughout life. The fourth indicates relatively stable health until a steep decrease approaches the end of life.
By applying these scenarios to economic models that utilize the concept of a statistical life (a common metric for the societal cost of diminishing mortality risk), the researchers calculated age-specific QALY values for each trajectory. In all four cases, the trend persisted: older individuals have a higher value per healthy year.
This existing policy may subtly bias decisions as a consequence. Relying on a uniform QALY threshold of 5 million yen could dismiss cost-effective treatments for older adults while endorsing inefficient ones for younger demographics. In an aging society, this distortion amplifies.
The research also reveals a less apparent insight. When populations enjoy prolonged better health, the economic value of an additional year of perfect health diminishes. Not because health is less significant, but because benefits are distributed across a longer, healthier life span. In populations where people remain vigorous into their later years, an additional year provides a smaller marginal advantage than in those where decline begins sooner.
Paying Less by Staying Healthier
Investing in initiatives that effectively increase healthy life expectancy can lead to reduced total healthcare expenses, even with longer lifespans. When more individuals pursue healthier aging trajectories, governments gain population-wide health improvements at a lower cost per QALY. Preventative measures alter the economic foundation.
“Our findings clarify the importance of extending healthy lifespans in relation to quality of life and age, enabling the development of measures for the rational distribution of medical resources,” Takashima elaborates.
The model can be customized by incorporating local demographic and economic data. As global populations age, the dilemma of how to assess health improvements will only become more pressing. This study does not propose that some lives have greater value than others; it illustrates how simplistic assumptions permeate funding choices, subtly influencing which treatments gain approval.
A treatment priced at 6 million yen per healthy year could be declined today for exceeding the established threshold. However, if that treatment is aimed at older adults, where a healthy year is valued at 9 million yen, rejecting it squanders potential value. In a future marked by longer lifespans and limited budgets, adopting a more adaptable perspective on the worth of a healthy year may assist policymakers in navigating aging as a variable they can influence, rather than an unavoidable expense.
Scientific Reports: 10.1038/s41598-025-29794-6
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