Accuracy of the Sequential Organ Failure Assessment Score for In-Hospital Mortality by Race and Relevance to Crisis Standards of Care

Abstract

Importance: Crisis Standards of Care (CSC) are guidelines for rationing health care resources during public health emergencies. The CSC adopted by US states ration intensive care unit (ICU) admission using the Sequential Organ Failure Assessment (SOFA) score, which is used to compare expected in-hospital mortality among eligible patients. However, it is unknown if Black and White patients with equivalent SOFA scores have equivalent in-hospital mortality.

Objective: To investigate whether reliance on SOFA is associated with bias against Black patients in CSC.

Design, setting, and participants: This cohort study was conducted using data from the eICU Collaborative Research Database of patients admitted to 233 US ICUs in 2014 to 2015. Included individuals were Black and White adult patients in the ICU, who were followed up to hospital discharge. Data were analyzed from May 2020 through April 2021.

Exposure: SOFA scores at ICU admission.

Main outcomes and measures: Hierarchical logistic regression with hospital fixed effects was used to measure the interaction between race and SOFA as a factor associated with in-hospital mortality, as well as the odds of death among Black and White patients with equivalent priority for resource allocation according to the SOFA-based ranking rules of 3 statewide CSC (denoted A, B, and C) under shortage conditions that were severe (ie, only patients with the highest priority would be eligible for allocation), intermediate (ie, patients in the highest 2 tiers would be eligible for allocation), or low (ie, only patients with the lowest priority would be at risk of exclusion).

Results: Among 111 885 ICU encounters representing 95 549 patients, there were 16 688 encounters with Black patients (14.9%) and 51 464 (46.0%) encounters with women and the mean (SD) age was 63.3 (16.9) years. The median (interquartile range) SOFA score was not statistically significantly different between Black and White patients (4 [2-6] for both groups; P = .19), but mortality was lower among Black individuals compared with White individuals with equivalent SOFA scores (odds ratio [OR], 0.98; 95% CI, 0.97-0.99; P < .001). This was associated with lower mortality among Black patients compared with White patients prioritized for resource allocation in 3 CSC under shortage conditions that were severe (system A: OR, 0.65; 95% CI, 0.58-0.74; P < .001; system B: OR, 0.70; 95% CI, 0.64-0.78; P < .001; system C: OR, 0.73; 95% CI, 0.67-0.80; P < .001), intermediate (system A: OR, 0.73; 95% CI, 0.67-0.80; P < .001; system B: OR, 0.83; 95% CI, 0.77-0.89; P < .001; system C: OR, 0.82; 95% CI, 0.77-0.89; P < .001), and low (system A: OR, 0.83; 95% CI, 0.77-0.89; P < .001; system C: OR, 0.86; 95% CI, 0.81-0.92; P < .001; not applicable for system B, which had fewer tiers). When SOFA-based ranking rules were adjusted for Black patients to simulate equitable allocation based on observed mortality, the proportion upgraded to higher priority ranged from 379 Black patient encounters (2.3%) in low shortage conditions to 2601 Black patient encounters (15.6%) in severe shortage conditions.

Conclusions and relevance: This study found that SOFA scores were associated with overestimated mortality among Black patients compared with White patients, and this was associated with a structural disadvantage for Black patients in CSC allocation systems. These findings suggest that guidelines should be revised to correct this inequity and alternative methods should be developed for more equitable triage.

Figure 1.. Sequential Organ Failure Assessment (SOFA) Score Distribution and SOFA-Associated Mortality

Patients with SOFA scores of 15 or higher were combined, given that there were few patients in this range and this was above the threshold for lowest priority in all Crisis Standards of Care. A, The percentage of Black and White individuals with each SOFA score were calculated. B, The mortality of Black and White individuals with each SOFA score was calculated. ^aA statistically significantly different proportion of Black and White individuals had a given SOFA score, determined by χ². ^bA statistically significantly different mortality was found between Black and White individuals at a given SOFA score determined by χ².

Figure 2.. Mortality in Sequential Organ Failure Assessment–Derived Tiers Recommended by Statewide Crisis Standards of Care

Hierarchical logistic regression with hospital-level fixed effects was used to calculate the odds ratio (OR) of death for Black compared with White patients with equivalent priority according to crisis standards of care. The odds of death for Black compared with White patients were lower in the highest priority tier (ie, priority 1) and lowest priority tier (ie, priority 3 for system B and priority 4 for systems A and C) of the 3 systems, regardless of the Sequential Organ Failure Assessment score threshold used (ie, for systems A, B, and C, scores of 6, 8, and 9, respectively, for highest priority; 12, 12, and 15, respectively, for lowest priority).