The relationship between hospital per diem billing and DRG reimbursement for urban trauma patients.

STUDY OBJECTIVE

To study the relationship between a trauma center per diem charges and medicare DRG reimbursement.

DESIGN

Retrospective comparison of charges ($630/day, $1500/ICU day) and hypothetical DRG reimbursement using medical records ICD-9 N and P codes and version 5.0 of grouper.

SETTING

An urban level I trauma center that participates in a trauma system that serves a population of 3 million people.

PATIENT POPULATION

Trauma patients > or = 16 years old (mean age of 32 years) admitted and discharged between 1/1/88 and 9/30/88. The group was 85% male, 75% black, with a blunt mechanism of injury in 64%. The mean ICU stay was 0.9 days, and the mean total length of stay was 5.0 days.

RESULTS

Total per diem charges were $8,652.159, and DRG reimbursement was $8,636,505, causing a net loss of $15,654, or 0.2% of charges. Mean charges and reimbursement did not differ for the entire group. The mean loss per patient was "8. Mean charges and reimbursement differed in penetrating trauma patients (mean loss = $138), as well as those with different lengths of stay. The correlation between charges and reimbursement was 0.42; for penetrating trauma patients, the correlation was 0.58 (p < .001).

CONCLUSION

If DRG reimbursement were provided for all admitted trauma patients, the amount would equal per diem rates. Trauma centers with similar patients and lengths of stay can use these per diem rates to estimate DRG reimbursement.