Impact of family mutual aid system for personal medical insurance accounts on paediatric patients’ outpatient utilization patterns and costs: a difference-in-differences analysis

This study explores the effect of the transformation of paediatric healthcare through the implementation of the Family Mutual Aid System (FMAS) for personal medical insurance accounts among paediatric patients at a children's hospital (Hospital A in Shanghai, China). We conducted a cohort study in the endocrinology department of Hospital A from August 2021 to July 2023 to assess the impact of FMAS enrolment on patients' annual outpatient visits, annual outpatient expenditures, and the allocation of these costs among the basic medical insurance pooling fund and patients' out-of-pocket expenses, with a further subdivision into online and offline consultations. Analysis employed a weighted difference-in-differences approach within a fixed-effects model following propensity score matching. The study encompassed 10 975 paediatric patients, divided into those enrolled in FMAS (observation group) and those not (control group). Enrolment in FMAS was associated with a statistically significant increase in annual outpatient visits by an average of 1.107, predominantly attributed to an uptick in offline consultations. Additionally, there was a substantial 38.9% rise in annual outpatient costs. Detailed analysis revealed a 52.5% increase in costs covered by the medical insurance pooling fund, while patients' out-of-pocket expenses decreased by an average of 69.2%. These findings highlight the beneficial effects of FMAS enrolment on healthcare service utilization and the risk-sharing mechanisms of medical insurance.