Equitably Allocating Resources during Crises: Racial Differences in Mortality Prediction Models

Abstract

Rationale: Crisis standards of care (CSCs) guide critical care resource allocation during crises. Most recommend ranking patients on the basis of their expected in-hospital mortality using the Sequential Organ Failure Assessment (SOFA) score, but it is unknown how SOFA or other acuity scores perform among patients of different races. Objectives: To test the prognostic accuracy of the SOFA score and version 2 of the Laboratory-based Acute Physiology Score (LAPS2) among Black and white patients. Methods: We included Black and white patients admitted for sepsis or acute respiratory failure at 27 hospitals. We calculated the discrimination and calibration for in-hospital mortality of SOFA, LAPS2, and modified versions of each, including categorical SOFA groups recommended in a popular CSC and a SOFA score without creatinine to reduce the influence of race. Measurements and Main Results: Of 113,158 patients, 27,644 (24.4%) identified as Black. The LAPS2 demonstrated higher discrimination (area under the receiver operating characteristic curve [AUC], 0.76; 95% confidence interval [CI], 0.76-0.77) than the SOFA score (AUC, 0.68; 95% CI, 0.68-0.69). The LAPS2 was also better calibrated than the SOFA score, but both underestimated in-hospital mortality for white patients and overestimated in-hospital mortality for Black patients. Thus, in a simulation using observed mortality, 81.6% of Black patients were included in lower-priority CSC categories, and 9.4% of all Black patients were erroneously excluded from receiving the highest prioritization. The SOFA score without creatinine reduced racial miscalibration. Conclusions: Using SOFA in CSCs may lead to racial disparities in resource allocation. More equitable mortality prediction scores are needed.

Keywords: acute respiratory failure; critical care; disaster planning; sepsis; triage.

Figure 1.

In-hospital mortality among white and Black patients by a mortality prediction score. (A) Sequential Organ Failure Assessment (SOFA) score. Those with a SOFA score of 8 or greater were included in one category, as few patients had very high SOFA scores. (B) LAPS2. In-hospital mortality was calculated for white and Black patients in each mortality prediction score category. The table beneath each graph demonstrates the total number of patients in each category. LAPS2 = version 2 of the Laboratory-based Acute Physiology Score.

Figure 2.

Calibration belts for selected mortality prediction scores among white and Black patients. (A) Original Sequential Organ Failure Assessment (SOFA) score. (B) Original LAPS2. (C) SOFA score without creatinine. A P value < 0.05 indicates miscalibration. Reported at the bottom of each graph are values of expected mortality for which observed values are significantly under (i.e., the model overestimates mortality) or over (i.e., the model underestimates mortality) the bisector using the 95% confidence interval (shaded area of the graph). LAPS2 = version 2 of the Laboratory-based Acute Physiology Score.

Figure 2.

Calibration belts for selected mortality prediction scores among white and Black patients. (A) Original Sequential Organ Failure Assessment (SOFA) score. (B) Original LAPS2. (C) SOFA score without creatinine. A P value < 0.05 indicates miscalibration. Reported at the bottom of each graph are values of expected mortality for which observed values are significantly under (i.e., the model overestimates mortality) or over (i.e., the model underestimates mortality) the bisector using the 95% confidence interval (shaded area of the graph). LAPS2 = version 2 of the Laboratory-based Acute Physiology Score.

Figure 3.

Black patients are inappropriately excluded from receiving the highest priority on the basis of in-hospital mortality in a commonly used crisis standard of care. In this simulated scenario, the Black patients with SOFA scores between 6 and 8 were sequentially reclassified as being the highest priority until the overall mortality risk for Black patients in the highest-priority category approximated, but did not exceed, that of white patients in this category. SOFA = Sequential Organ Failure Assessment.