To explore how the subjective life expectancy of patients with chronic diseases affects their medical expenditure and provide a policy intervention perspective for improving the quality of life of patients with chronic diseases.

The data from the China Health and Retirement Longitudinal Study (CHARLS) were used. A total of 9 949 samples with any chronic disease at three time points in 2015 (T1), 2018 (T2), and 2020 (T3) were selected. Information such as subjective life expectancy, annual medical expenditure, frequency of outpatient and inpatient visits from modules including health status, medical service utilization records, family economy, and individual basic information was used. A cross-lagged model was applied to test the interaction between subjective life expectancy and medical expenditure and explore the mediating effect of medical resource utilization.

The results of the standardized cross-lagged analysis showed that the subjective life expectancy T1 of patients with chronic diseases significantly negatively predicted the medical expenditure T2 (β=-0.043, P < 0.01), and the medical expenditure T2 significantly negatively predicted the subjective life expectancy T3 (β=-0.043, P < 0.01); the medical expenditure T1 of patients with chronic diseases significantly negatively predicted the subjective life expectancy T2 (β=-0.034, P < 0.05), and the subjective life expectancy T2 significantly negatively predicted the medical expenditure T3 (β=-0.043, P < 0.01). Medical resource utilization had a mediating effect in this process (β=-0.02, P < 0.05).

There is a complex interaction mechanism between the subjective life expectancy and medical expenditure of patients with chronic diseases. There may be a vicious cycle in which health anxiety leads to the deterioration of the condition and an increase in medical expenditure, which further aggravates anxiety, as well as the phenomenon of excessive medical treatment due to pessimistic health expectations. This indicates the value of formulating differentiated psychological intervention policies for different groups to improve the quality of life of patients with chronic diseases.