DRGs and hospital case records: implications for Medicare case mix accuracy

Area of Science:

• Health Services Research
• Healthcare Economics
• Medical Billing and Reimbursement

Background:

• Medicare's transition to a Diagnosis-Related Group (DRG)-based prospective payment system necessitates accurate hospital case-mix data.
• Uncertainty exists regarding the adequacy of federal data for setting DRG prices and evaluating hospital case mix.

Purpose of the Study:

• To compare Medicare case mix data derived from billing claims with actual case mix documented in medical records.
• To assess the accuracy of DRG assignment based on submitted claims versus medical record documentation.

Main Methods:

• A comparative analysis of Medicare claims data and medical record charts for patients in Minneapolis-St. Paul hospitals.
• Evaluation of DRG (Diagnosis-Related Group) code concordance between billing submissions and medical records.

Main Results:

• The DRG derived from Medicare billing claims matched the DRG from the medical record for approximately 50% of patients.
• These data mismatches led to a statistically significant understatement of hospital case mix.

Conclusions:

• Inaccurate Medicare billing data can lead to an underestimation of hospital case mix.
• Discrepancies in DRG assignment have significant implications for setting accurate DRG prices and ensuring equitable hospital reimbursement.