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J Med Syst. 2018 Mar 22;42(5):81. doi: 10.1007/s10916-018-0936-3.

Validation of the All Patient Refined Diagnosis Related Group (APR-DRG) Risk of Mortality and Severity of Illness Modifiers as a Measure of Perioperative Risk.

Author information

1
Department of Anesthesiology & Critical Care, Memorial Sloan Kettering Cancer Center, New York, NY, USA. mccormp1@mskcc.org.
2
Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
3
Department of Anesthesiology, Perioperative and Pain Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
4
Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
5
Department of Geriatrics and Palliative Care, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
6
Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.

Abstract

The All Patient Refined Diagnosis Related Group (APR-DRG) is an inpatient visit classification system that assigns a diagnostic related group, a Risk of Mortality (ROM) subclass and a Severity of Illness (SOI) subclass. While extensively used for cost adjustment, no study has compared the APR-DRG subclass modifiers to the popular Charlson Comorbidity Index as a measure of comorbidity severity in models for perioperative in-hospital mortality. In this study we attempt to validate the use of these subclasses to predict mortality in a cohort of surgical patients. We analyzed all adult (age over 18 years) inpatient non-cardiac surgery at our institution between December 2005 and July 2013. After exclusions, we split the cohort into training and validation sets. We created prediction models of inpatient mortality using the Charlson Comorbidity Index, ROM only, SOI only, and ROM with SOI. Models were compared by receiver-operator characteristic (ROC) curve, area under the ROC curve (AUC), and Brier score. After exclusions, we analyzed 63,681 patient-visits. Overall in-hospital mortality was 1.3%. The median number of ICD-9-CM diagnosis codes was 6 (Q1-Q3 4-10). The median Charlson Comorbidity Index was 0 (Q1-Q3 0-2). When the model was applied to the validation set, the c-statistic for Charlson was 0.865, c-statistic for ROM was 0.975, and for ROM and SOI combined the c-statistic was 0.977. The scaled Brier score for Charlson was 0.044, Brier for ROM only was 0.230, and Brier for ROM and SOI was 0.257. The APR-DRG ROM or SOI subclasses are better predictors than the Charlson Comorbidity Index of in-hospital mortality among surgical patients.

KEYWORDS:

Case mix; Comorbidity; Diagnostic related group; Perioperative mortality; Risk adjustment

PMID:
29564554
PMCID:
PMC6750741
DOI:
10.1007/s10916-018-0936-3
[Indexed for MEDLINE]
Free PMC Article

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