Risk adjustment: beyond patient classification systems

Area of Science:

• Health Economics
• Hospital Management
• Healthcare Policy

Background:

• Diagnosis Related Groups (DRGs) are international standards for hospital reimbursement.
• Existing DRG versions, often based on American models, may not accurately reflect European healthcare costs.
• Understanding cost variability is crucial for effective hospital resource allocation and policy-making.

Purpose of the Study:

• To assess the explanatory power of Diagnosis Related Groups (DRGs) and their associated weights on patient cost variability.
• To analyze the impact of clinical factors (severity, comorbidities, complications) and socioeconomic status on patient costs.
• To evaluate the suitability of American DRG systems for European healthcare contexts.

Main Methods:

• Analysis of 35,262 hospital discharges from two public hospitals in Barcelona.
• Calculation of Health Care Financing Administration (HCFA)-DRGs and All Patient Refined (APR)-DRGs.
• Adjustment for patient severity, comorbidities, complications, and socioeconomic status using established methodologies and linear regression models.

Main Results:

• Medicare's DRG-weights explained only 19% of patient cost variability.
• Cost-based DRG-weights demonstrated significantly higher explanatory power (38-42%).
• Exclusion of outliers and inclusion of clinical/socioeconomic variables increased explanatory power to 49-51%.

Conclusions:

• American DRG-weights are suboptimal for European healthcare settings.
• Cost-based DRG-weights and outlier management substantially enhance cost variability explanation.
• Adapting DRG classification systems to local healthcare environments is recommended for accurate hospital production cost valuation in Europe.