All Patient Refined-Diagnosis Related Groups’ (APR-DRGs) Severity of Illness and Risk of Mortality as predictors of in-hospital mortality

Abstract

The aims of this study were to assess All-Patient Refined Diagnosis-Related Groups' (APR-DRG) Severity of Illness (SOI) and Risk of Mortality (ROM) as predictors of in-hospital mortality, comparing with Charlson Comorbidity Index (CCI) and Elixhauser Comorbidity Index (ECI) scores. We performed a retrospective observational study using mainland Portuguese public hospitalizations of adult patients from 2011 to 2016. Model discrimination (C-statistic/ area under the curve) and goodness-of-fit (R-squared) were calculated. Our results comprised 4,176,142 hospitalizations with 5.9% in-hospital deaths. Compared to the CCI and ECI models, the model considering SOI, age and sex showed a statistically significantly higher discrimination in 49.6% (132 out of 266) of APR-DRGs, while in the model with ROM that happened in 33.5% of APR-DRGs. Between these two models, SOI was the best performer for nearly 20% of APR-DRGs. Some particular APR-DRGs have showed good discrimination (e.g. related to burns, viral meningitis or specific transplants). In conclusion, SOI or ROM, combined with age and sex, perform better than more widely used comorbidity indices. Despite ROM being the only score specifically designed for in-hospital mortality prediction, SOI performed better. These findings can be helpful for hospital or organizational models benchmarking or epidemiological analysis.

Convergent Validity of 2 Widely Used Methodologies for Calculating the Hospital Standardized Mortality Ratio in Flanders, Belgium

“…At discharge, APR-DRGs’ ROM has been shown to be a good predictor of in-hospital mortality in different settings and disease groups 12–14,18,19 . Consistent with our findings for the Elixhauser score, these studies reported superior discrimination by ROM compared with (different variants of) the Charlson and Elixhauser indices 12,14,18,19 . This is not surprising given that ROM is specifically designed to estimate the likelihood of death within APR-DRG groups, whereas the Charlson and Elixhauser indices were solely developed for the quantification of comorbidities.…”

“…Measures of model performance indicated superiority of the 3M model, suggesting that the APR-DRG ROM subclasses are better predictors of in-hospital mortality than the set of variables [12][13][14]18,19 Consistent with our findings for the Elixhauser score, these studies reported superior discrimination by ROM compared with (different variants of ) the Charlson and Elixhauser indices. 12,14,18,19 This is not surprising given that ROM is specifically designed to estimate the likelihood of death within APR-DRG groups, whereas the Charlson and Elixhauser indices were solely developed for the quantification of comorbidities. Also, the APR-DRG severity of illness (SOI) indicator has been found to be a better predictor of in-hospital mortality than the comorbidity indices.…”

“…The ROM classification is based on interactions of age, type of surgical procedure, comorbidity, and the principal diagnosis, and has been validated previously. [12][13][14] Whereas the 3M™-Core Grouping Software generates separate indicators for ROM at admission and ROM at discharge, the 3M model3M model uses the latter for risk adjustment, thereby taking into account not only comorbidities present on admission (POA) but also those due to complications generated during the hospital stay. The Elixhauser comorbidity score, on the other hand, is typically restricted to POA diagnoses.…”

Coding for Physical Restraint Status Among Hospitalized Patients: a 2019 National Inpatient Sample Analysis

“…This logistic regression incorporates the sampling methodology of the NIS, so it explicitly considers the NIS stratum and hospital identifier as part of variance calculations. In this model, age ( z score), sex, race, admission type (elective vs. non-elective), hospital bed size (small/medium/large), primary service line, region, income quartile of the patient’s ZIP code, and patient severity (defined based off of All Patient Refined-Diagnosis Related Groups’ (APR-DRGs) Severity of Illness) 21 , 22 are descriptor variables. As a sensitivity analysis, this analysis was repeated separately for patients with a procedure code for mechanical ventilation during hospitalization.…”

Racial and socioeconomic disparities in the advanced treatment of medically intractable pediatric epilepsy

“…The APR-DRG is a standardized method of assessing the comorbidities and risk of mortality based on the diagnosis and clinical condition of the patient. 18,19 The Healthcare Cost and Utilization Project data provided this information for each patient. The location of the patient was provided based on the 6-category classification of the National Center for Health Statistics.…”