Table 1_Association of DRG-based payment reform with inpatient costs and resource use among older adults: an interrupted time series study in a county-level referral hospital in China.docx

Supplementary analyses used monthly aggregated models with Newey-West standard errors and exploratory disease-group heterogeneity analyses.</p>Results<p>In the adjusted admission-level interrupted time series models, the implementation of DRG was associated with an immediate reduction in OOP costs (β₂ = −1360.617 CNY) and a more pronounced negative trend post-implementation (β₃ = −106.705 CNY per month).

LOS experienced an immediate increase (β₂ = 0.831 days) and continued to rise in comparison to the pre-implementation trend (β₃ = 0.077 days per month). Total-cost findings differed by the analytical level: no statistically significant immediate or slope change was observed in the admission-level model (β₂ = −84.683 CNY; β₃ = 34.844 CNY/month), whereas the monthly aggregated model showed an immediate decrease (β₂ = −851.064 CNY) followed by an upward post-intervention slope change (β₃ = 75.090 CNY/month).

Changes in total costs and most cost components were not consistent across different model specifications. Monthly aggregated analyses indicated directionally similar results for OOP costs and LOS. Disease-group analyses revealed that reductions in OOP costs were more substantial for neoplasms, digestive diseases, and circulatory diseases, while increases in LOS were primarily observed in certain circulatory and respiratory conditions.</p>Conclusion<p>Among older adult inpatients in a county-level referral hospital in China, DRG-based payment reform was associated with lower patient OOP but longer hospital stays.

Its effects on total spending and cost composition were less consistent and varied across disease groups.</p>