Predictive performance of the SOFA and mSOFA scoring systems for predicting in-hospital mortality in the emergency department

Background: The Sequential Organ Failure Assessment (SOFA) and modified SOFA (mSOFA) are risk stratification systems which incorporate respiratory, coagulatory, liver, cardiovascular, renal, and neurologic systems to quantify the overall severity of acute disorder in the intensive care unit.

Objective: To evaluate the prognostic performance of the SOFA and mSOFA scores at arrival for predicting in-hospital mortality in the emergency department (ED).

Methods: All adult patients with an Emergency Severity Index (ESI) of 1-3 in the ED of Imam Reza Hospital, northeast of Iran were included from March 2016 to March 2017. The predictive performance of the SOFA or mSOFA scores were expressed in terms of accuracy (Brier Score, BS and Brier Skill Score, BSS), discrimination (Area Under the Receiver Operating Characteristic Curve, AUC), and calibration.

Results: A total of 2205 patients (mean age 61.8 ± 18.5 years, 53% male) were included. The overall in-hospital mortality was 19%. For SOFA and mSOFA the BS was 0.209 and 0.192 and the BSS was 0.11 and 0.09, respectively. The estimated AUCs of SOFA and mSOFA models were 0.751 and 0.739, respectively. No significant difference was observed between the AUCs (P = 0.186). The Hosmer-Lemeshow test did not show that the predictions deviated from the true probabilities. Also, the calibration plots revealed good agreement between the actual and predicted probabilities.

Conclusion: The SOFA and mSOFA scores demonstrated fair discrimination and good calibration in predicting in-hospital mortality when applied to ED. However, further external validation studies are needed before their use in routine clinical care.