Analysis and optimization of inpatient cost structure for fracture patients under the implementation of the DRG policy.

Background: Fractures are among the most common traumatic injuries in China, with rising incidence driven by population aging, traffic accidents, and sports injuries. They impose a heavy economic burden due to high treatment costs and prolonged rehabilitation. To improve cost efficiency, China launched a nationwide Diagnosis-Related Groups (DRG) payment reform in 2019. While DRG has shown positive effects in controlling costs for chronic diseases, its impact on trauma-related conditions like fractures remains unclear due to clinical complexity and treatment variability. Existing research mostly focuses on epidemiology, lacking economic evaluations under the DRG system. This study aims to assess how DRG reform influences the inpatient cost structure of fracture patients and explore differential effects across comorbidity and fracture types, providing evidence for more refined payment strategies in trauma care. Methods: Using data from 12,101 hospitalized fracture patients (ICD-10 codes S22-S92) admitted to a tertiary hospital in Anshan, Liaoning Province between 2018 and 2024, we conducted a structural change analysis to assess shifts in the composition of inpatient costs before and after the introduction of the DRG payment system. An interrupted time series (ITS) model was applied to estimate both the immediate impact and the longitudinal trend changes associated with the DRG reform initiated on July 1, 2019. In addition, gray relational analysis was employed to further examine the relative contribution of different cost categories to overall expenditure. Results: A total of 12,101 fracture inpatients were included, covering the entire period before and after the DRG reform. Significant changes in the cost structure were observed post-implementation. The median drug cost decreased from 3,416.06 CNY to 2,796.74 CNY (a reduction of 18.1%). Although the proportion of consumables costs slightly increased (median rose from 7,358.12 CNY to 7,465.64 CNY), the growth rate significantly slowed ( Conclusion: The DRG-based payment reform effectively controlled pharmaceutical expenditures while increasing diagnostic costs, leading to fracture-type-specific shifts in treatment structure and highlighting the need for differentiated management strategies. This study provides empirical evidence to support the optimization of DRG payment standards and the advancement of healthcare payment reform.