Cost Homogenization and System-Level Drivers in Plateau Laparoscopic Cholecystectomy: Failure and Reconstruction of Traditional Cost-Control Models in the DRG Era

Background: Under the DRG/DIP payment reform, the cost structure and its driving factors for laparoscopic cholecystectomy (LC) in resource-limited plateau regions remain unclear. Methods: Based on a single-center cohort of 605 plateau LC patients from May 2020 to October 2025, natural log transformation was applied to total hospitalization costs. Pearson/Spearman correlation, multivariate linear regression (traditional clinical model vs system-driven model with year dummies), and quantile regression were used. Results: Mean hospitalization cost 8097.49+/-936.85 CNY, CV=11.6%, Gini=0.062, demonstrating high homogenization. Traditional six-variable clinical model yielded R^2=0.008 (F=0.78, P=0.587), no significant predictors. The system-driven model achieved R^2=0.143 (F=3.42, P=0.001), with year dummies as dominant predictors. The study proposes the SAO (System-Allocation-Outcome) paradigm to replace the traditional SPO framework.