Payment modality and cumulative hospitalization expenditures among stroke rehabilitation patients in five Chinese hospitals

Background Stroke rehabilitation can generate substantial inpatient expenditure, yet evidence on how payment modality is associated with cumulative expenditure and expenditure composition remains limited. We examined these associations among rehabilitation patients in five Chinese hospitals and assessed whether they varied by hospital tier and disease chronicity. Methods This retrospective observational study included 8,041 eligible admissions from January 2018 to December 2025, aggregated to 4,945 unique patients by identification number. Expenditures and length of stay were summed across included admissions for each patient. Total gross inpatient expenditure was divided into rehabilitative therapy, hospital bed, nursing care, medications, laboratory/examination, and other recorded services. Patient characteristics included sex, age, insurance, disease chronicity, hospitalization count, cumulative length of stay, and Charlson Comorbidity Index (CCI). Generalized linear models with a gamma distribution and log link and robust standard errors estimated adjusted associations; payment-by-tier and payment-by-chronicity interactions were examined. Results Mean cumulative hospitalization expenditure was US$11,317 (SD US$15,231; median US$6,313, IQR US$2,677–13,925). Rehabilitative therapy represented 31.2% of expenditure, medications 24.4%, other recorded services 19.0%, hospital bed 12.1%, laboratory/examination 7.6%, and nursing care 5.7%. Compared with fee-for-service, DRG/DIP payment was associated with significantly lower total expenditure ( β = −0.077, p = 0.010) and per-diem payment with a larger negative association ( β = −0.418, p < 0.001). The per-diem association was more negative in tertiary than in secondary hospitals (interaction β = −0.161, p = 0.017) and among patients with longer disease chronicity (3–6 months: β = −0.203, p = 0.004; >6 months: β = −0.351, p < 0.001). Conclusion DRG/DIP and per-diem payment were associated with lower cumulative hospitalization expenditure than fee-for-service after adjustment for measured patient and hospital characteristics. Because payment assignment was non-random and key clinical severity measures were unavailable, these findings should be interpreted as associations rather than causal effects.