Updated SOFA-2 Score Enhances Measurement of Organ Dysfunction in ICU Patients

A new version of the Sequential Organ Failure Assessment (SOFA) score, known as SOFA-2, has been introduced to align organ dysfunction measurement in critically ill adults with current clinical practices. Published in JAMA on October 29, the revised tool is the result of an international effort to update the original 1996 SOFA score, which had remained unchanged despite evolving treatment modalities and technologies.

SOFA-2 was developed through an eight-stage process, incorporating expert consensus and federated analysis of more than 3.3 million ICU admissions across nine countries. The updated score retains the original six organ systems—brain, respiratory, cardiovascular, liver, kidney, and hemostasis—but introduces revised thresholds and variables. These changes account for contemporary use of vasopressors, mechanical support devices, and updated laboratory parameters. Proposed additions involving gastrointestinal and immune systems were evaluated but ultimately excluded due to insufficient predictive or content validity.

In validation studies, SOFA-2 showed predictive validity for ICU mortality, with an area under the receiver operating characteristic (AUROC) curve of 0.79, compared to 0.77 for the original score. This performance was consistent across cohorts from high-, middle-, and low-income healthcare settings.

A reclassification analysis comparing SOFA-1 and SOFA-2 revealed that 49 percent of patients received the same total score under both systems, while 11 percent received a higher score with SOFA-2 and 40 percent received a lower one. Mortality rates varied accordingly: 13.5 percent for patients with higher SOFA-2 scores, 8.6 percent for those with lower scores, and 4.7 percent when scores were unchanged.

The study included data from 1319 intensive care units and used both internal and external validation cohorts. While ICU mortality was the sole outcome used to assess predictive validity, the authors note that it is a consistently recorded metric across datasets and correlates with other clinical endpoints.

SOFA-2 was designed for broad applicability and reflects current standards in organ support. According to the authors, further evaluation will be needed to assess its utility outside the ICU setting or for other outcomes.