Climate risks, multi-tier medical insurance systems, and health inequality: evidence from China's middle-aged and elderly populations.

Background: Against the backdrop of increasing population aging, the uncertainty and irreversibility of climate change have a significant impact on the health and healthcare burden of the elderly. However, it remains uncertain whether the multi-tiered medical insurance system disproportionately influences the health impacts of climate risks.

Methods: Using data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2020, matched with urban climate risk variables, we employ a multi-dimensional panel fixed effects model and an instrumental variable model to examine the impact of climate risks on the health of the middle-aged and elderly, while also investigating the unequal effects of the multi-tiered medical insurance system.

Results: Climate risks significantly worsened the self-reported health of the middle-aged and elderly (β = 0.073, P = 0.089), and increased both total medical costs (β = 2.570, P = 0.012) and out-of-pocket expenses (β = 2.652, P = 0.003). Notably, the increases in hospitalization costs (β = 0.721, P = 0.004) and out-of-pocket hospitalization expenses (β = 0.706, P = 0.036) are particularly prominent. The current multi-tiered medical insurance system results in unequal impacts of climate risks on health and medical costs. Specifically, urban employee medical insurance and commercial medical insurance effectively improve the health outcomes of elderly individuals affected by climate risks. Urban residents' medical insurance significantly reduces both total medical costs and out-of-pocket expenses for the elderly, whereas the new rural cooperative medical insurance shows no significant mitigating effect. Additionally, there is no evidence to suggest that the integration of urban and rural resident medical insurance can reduce the medical burden on rural elderly populations caused by climate risks. Our long-term projections indicate that, under both the SSP245 and SSP585 scenarios, the increase in elderly healthcare costs due to climate risks is irreversible. However, restrictive climate policies would yield significant health benefits, potentially reducing per capita medical costs for the elderly by nearly 50%.

Conclusions: The decentralized multi-tier medical insurance system leads to significant inequality in the health impacts of climate risks. Our study emphasizes the critical role of reforming the existing social medical insurance system and implementing climate policies to protect the health of elderly populations.