Enrollment or dropout: dynamics of social health insurance participation among Chinese children and their impact on health service utilization and medical expenses.

Since children's participation in social health insurance (SHI) in China is voluntary, fluctuations in enrollment or dropout are inevitable. Using data from the two waves of the China Family Panel Study in 2020 and 2022, this study aims to examine these participation dynamics and their impact on children's health service utilization and medical expenses. Specifically, a balanced panel of 1958 children under the age of 15 was constructed, first-difference and difference-in-difference models were employed to assess the factors influencing children's SHI enrollment or dropout, as well as the impact of these changes on health service utilization and medical expenses. Robustness checks were conducted after excluding new enrollees and dropouts separately. Our analysis showed that between 2020 and 2022, 263 children (13.4%) were newly enrolled in SHI, while 135 (6.9%) dropped out. Maternal SHI enrollment increased the likelihood of children's enrollment and reduced the probability of dropout. Children with commercial insurance were 34% less likely to enroll and 58% more likely to dropout. Compared to children with unchanged participation status, newly enrolled children were about 8% more likely to use outpatient services and had 77% higher medical expenses in the past year, whereas no significant changes were observed among those who dropped out. These findings highlight the dynamic nature of children's SHI participation in China and suggest that passive enrollment policies and parental participation could help promote universal coverage. Improving the reimbursement system, particularly for children's outpatient care, is also recommended.