Performance of intensive care unit severity scoring systems across different ethnicities in the USA: a retrospective observational study

Abstract

Summary Background Despite wide use of severity scoring systems for case-mix determination and benchmarking in the intensive care unit (ICU), the possibility of scoring bias across ethnicities has not been examined. Guidelines on the use of illness severity scores to inform triage decisions for allocation of scarce resources, such as mechanical ventilation, during the current COVID-19 pandemic warrant examination for possible bias in these models. We investigated the performance of the severity scoring systems Acute Physiology and Chronic Health Evaluation IVa (APACHE IVa), Oxford Acute Severity of Illness Score (OASIS), and Sequential Organ Failure Assessment (SOFA) across four ethnicities in two large ICU databases to identify possible ethnicity-based bias. Methods Data from the electronic ICU Collaborative Research Database (eICU-CRD) and the Medical Information Mart for Intensive Care III (MIMIC-III) database, built from patient episodes in the USA from 2014–15 and 2001–12, respectively, were analysed for score performance in Asian, Black, Hispanic, and White people after appropriate exclusions. Hospital mortality was the outcome of interest. Discrimination and calibration were determined for all three scoring systems in all four groups, using area under receiver operating characteristic (AUROC) curve for different ethnicities to assess discrimination, and standardised mortality ratio (SMR) or proxy measures to assess calibration. Findings We analysed 166 751 participants (122 919 eICU-CRD and 43 832 MIMIC-III). Although measurements of discrimination were significantly different among the groups (AUROC ranging from 0·86 to 0·89 [p=0·016] with APACHE IVa and from 0·75 to 0·77 [p=0·85] with OASIS), they did not display any discernible systematic patterns of bias. However, measurements of calibration indicated persistent, and in some cases statistically significant, patterns of difference between Hispanic people (SMR 0·73 with APACHE IVa and 0·64 with OASIS) and Black people (0·67 and 0·68) versus Asian people (0·77 and 0·95) and White people (0·76 and 0·81). Although calibrations were imperfect for all groups, the scores consistently showed a pattern of overpredicting mortality for Black people and Hispanic people. Similar results were seen using SOFA scores across the two databases. Interpretation The systematic differences in calibration across ethnicities suggest that illness severity scores reflect statistical bias in their predictions of mortality.

Contraindications to the Initiation of Veno-Venous ECMO for Severe Acute Respiratory Failure in Adults: A Systematic Review and Practical Approach Based on the Current Literature

“…The Sepsis-Related/Sequential Organ Failure Assessment Score (SOFA) was created in 1996 as a result of an initiative of the European Society of Intensive Care Medicine “to quantitatively and objectively describe the degree of organ dysfunction/failure over time in groups of patients or even in individual patients” [ 129 ]. Although, as already stated in its first description, “it is important to realize that the SOFA score is designed not to predict outcome but to describe a sequence of complications in the critically ill”, it has increasingly been used to predict mortality in various diseases/conditions [ 130 , 131 , 132 , 133 , 134 , 135 ]. All of these trials only found a fair precision in predicting mortality [ 82 ], which obviously varies across different groups of patients.…”

Comparison of prognosis predictive value of 4 disease severity scoring systems in patients with acute respiratory failure in intensive care unit

“…[ 15 ] This is why in our study we investigated the 4 scoring systems, 3 of which are already widely used in ICU settings, and 1 of which is a newly developed generic scoring system. [ 16 , 17 ] APS III is extracted from the APACHE III system, a widely used scoring system in ICU, which was first proposed by Knaus et al [ 18 ] in 1981 and has been updated several times and validated in ICU conditions. [ 19 ] OASIS was actually developed in 2013 from the APACHE IV system by screening and simplifying its parameters.…”

Origin of Sepsis Associated with the Short-Term Mortality of Patients: A Retrospective Study Using the eICU Collaborative Research Database

“…The data can be publicly used after registration, and many applications have been developed using this database, including the development of machine learning algorithms, decision support tools, and clinical research. 13 , 14 …”