Diagnosis‐Intervention Packet (DIP) Payment Standard Versus Actual In‐Hospital Cost: Insights From a Chinese County Hospital
Chun‐Ying WangABSTRACT
Objectives
Evaluate alignment between calculated Diagnosis‐Intervention Packet (DIP) payment entitlements and observed inpatient costs and identify insurance, regional, and disease‐group patterns in payment‐cost misalignment.
Study Design
Retrospective observational study of all inpatient final settlements (2023–2024).
Methods
We analyzed 23,597 discharge settlements using linear mixed‐effects models with DIP group as a random intercept and heteroskedasticity‐robust standard errors to compare signed payment‐cost gaps. Robustness was assessed with model diagnostics and 1st−99th percentile trimming; separate gamma‐log mixed models evaluated total cost and calculated DIP payment. Analyses compared insurance type (UEBMI vs. URRBMI) and insured region (local vs. non‐local); high‐volume DIP groups were defined as those with at least 150 admissions, and groups with cost‐to‐calculated‐payment ratios of at least 3.0 were profiled as descriptive outliers.
Results
Mean total cost per admission was CNY 14,604 and mean calculated DIP payment was CNY 4865, equivalent to 33.3% of observed inpatient cost. The mean signed payment‐cost gap was ‐CNY 9739. Adjusted gaps were more negative for UEBMI than URRBMI (‐CNY 12,971 vs. ‐CNY 8936) and for non‐local than local admissions (‐CNY 11,796 vs. ‐CNY 9279); trimmed analyses were consistent. Ten high‐volume cerebrovascular, oncologic, renal, cardiac, infectious, and pancreatic clusters accounted for 18.8% of episodes and 35.6% of the cohort's net payment‐cost shortfall.
Conclusions
At this county hospital, calculated DIP payments were equivalent to about one‐third of observed inpatient spending, with concentrated shortfalls in complex neurovascular and oncologic groups and larger adjusted gaps among UEBMI and non‐local admissions. These associations should not be interpreted causally because detailed clinical severity and comorbidity were unavailable. Although site‐specific, the findings suggest that case‐based payment systems may require severity adjustment, outlier protection, and periodic recalibration to reduce systematic payment‐cost misalignment while safeguarding access to complex care.