Predictive Value of Sequential Organ Failure Assessment Score across Patients with and without COVID-19 Infection.

Rationale Sequential Organ Failure Assessment (SOFA) scores are commonly used in Crisis Standards of Care policies to assist in resource allocation. The relative predictive value of SOFA by COVID-19 infection status and among racial/ethnic subgroups within patients infected with COVID-19 is unknown. Objective To evaluate the accuracy and calibration of SOFA in predicting hospital mortality by COVID-19 infection status and across racial/ethnic subgroups. Methods We performed a retrospective cohort study of adult admissions to the University of Miami Hospital and Clinics inpatient wards (July 1, 2020-April 1, 2021). We primarily considered maximum SOFA within 48 hours of hospitalization. We assessed accuracy using the area under the receiver operating characteristic curve (AUROC) and created calibration belts. Considered subgroups were defined by COVID-19 infection status (by SARS-CoV-2 PCR testing) and prevalent racial/ethnic minorities. Comparisons across subgroups were made with DeLong testing for discriminative accuracy and visualization of calibration belts. Results Our primary cohort consisted of 20,045 hospitalizations of which 1,894 (9.5%) were COVID-19-positive. SOFA was similarly accurate for COVID-19-positive (AUROC 0.835) and COVID-19-negative (AUROC 0.810, p=0.15) admissions, but was slightly better calibrated in COVID-19-positive patients. For those with critical illness, maximum SOFA score accuracy at critical illness onset also did not differ by COVID-19 status (AUROC, COVID-19-positive vs -negative: intensive care unit admissions-0.751 vs 0.775, p=0.46; mechanically ventilated-0.713 vs 0.792, p=0.13) and calibration was again better for COVID-19-positive patients. Among COVID-19 patients, SOFA accuracy was similar between non-Hispanic Whites (AUROC 0.894) and racial/ethnic minorities (Hispanic Whites: AUROC 0.824 [p vs non-Hispanic Whites=0.05]; non-Hispanic Blacks: AUROC 0.800 [p=0.12]; Hispanic Blacks: AUROC 0.948 [p=0.31]). This similar accuracy was also found for those without COVID-19 (non-Hispanic Whites: AUROC 0.829; Hispanic Whites: AUROC 0.811 [p=0.37]; Hispanic Blacks: AUROC 0.828 [p=0.97]; non-Hispanic Blacks: AUROC 0.867 [p=0.46]). SOFA was well calibrated for all racial/ethnic groups with COVID-19, but estimated mortality more variably and performed less well across races/ethnicities without COVID-19. Conclusions SOFA accuracy does not differ by COVID-19 status and is similar among racial/ethnic groups both with and without COVID-19. Calibration is better for COVID-19 infected patients and, among those without COVID-19, varies by race/ethnicity.