Use of the All Patient Refined-Diagnosis Related Group (APR-DRG) Risk of Mortality Score as a Severity Adjustor in the Medical ICU

Syed Ali Riaz,Feroza Daroowalla,Paul Richman,Ruel Garcia,Guangxiang Zhang,John J Chen,Erin Healy,Daniel Baram

doi:10.4137/ccrpm.s544

Abstract

To evaluate the performance of APR-DRG (All Patient Refined-Diagnosis Related Group) Risk of Mortality (ROM) score as a mortality risk adjustor in the intensive care unit (ICU). Retrospective analysis of hospital mortality. Medical ICU in a university hospital located in metropolitan New York. 1213 patients admitted between February 2004 and March 2006. Mortality rate correlated significantly with increasing APR-DRG ROM scores (p < 0.0001). Multiple logistic regression analysis demonstrated that, after adjusting for patient age and disease group, APR-DRG ROM was significantly associated with mortality risk in patients, with a one unit increase in APR-DRG ROM associated with a 3-fold increase in mortality. APR-DRG ROM correlates closely with ICU mortality. Already available for many hospitalized patients around the world, it may provide a readily available means for severity-adjustment when physiologic scoring is not available.

Highlights

If an intensive care unit (ICU) institutes a systematic change in practice and the mortality rate is unchanged, it is possible that the change in practice was effective but that the ICU severity increased hiding the actual improvement in outcome
The association of mortality and All Patient Refined-Diagnosis Related Group (APR-DRG) Risk of Mortality (ROM) scores was consistent within various disease groups, i.e. higher APR-DRG ROM scores tended to be associated with increased mortality (Table 1)
The crude odds ratios of two higher levels (“High” and “Extreme”) of APR-DRG ROM scores are statistically significantly higher than the “Low” ROM score (OR for “High vs. Low”= 10.15 [95% confidence intervals (CI): 3.13,32.86]; OR for “Extreme vs. Low” = 32.57 [95% CI: 10.24,103.58]), the difference between level “Moderate” and level “Low” was less dramatic (OR for “Moderate vs. Low” = 2.90 [95% CI: 0.79,10.59]) (Fig. 1)

Summary

Methods

Stony Brook University Medical Center’s Medical ICU is a 12 bed ICU in a 504 bed tertiary-care university hospital located in the metropolitan New York area. It is a closed ICU managed by boardcertified pulmonary/critical care attendings who supervise medical housestaff and pulmonary/ critical care fellows. 1213 patients admitted to the medical ICU between February 1, 2004 and March 31, 2006 were identified. APR-DRG ROM (3M, Version 20) was available through the University Hospital Consortium, as Stony Brook University Medical Center is a member of this organization. APR-DRG calculations are based on electronic bills submitted by the hospital at time of patient discharge after chart data extraction by certified professional coders. Primary DRG billing diagnosis was identified and divided into 5 groups: cardiology, gastroenterology, neurology, pulmonary, and other

Results

Discussion

Conclusion