SOFA-2 versus SOFA for mortality risk assessment in ICU patients with acute cholangitis: a retrospective cohort study using MIMIC-IV and eICU

Abstract Background Acute cholangitis (AC) can progress rapidly to organ failure and death. The Sequential Organ Failure Assessment-2 (SOFA-2) is a recently revised organ-dysfunction score, but whether it adds disease-specific value beyond SOFA in AC is unknown. We compared SOFA-2 with SOFA for mortality risk assessment in ICU patients with AC. Methods We conducted a retrospective cohort study using MIMIC-IV v3.1 as the primary dataset and eICU for cross-database assessment. Adults with AC meeting Tokyo Guidelines 2018 diagnostic criteria were included. Day-1 SOFA-2 and SOFA were reconstructed over the first 24 h after ICU admission. The primary outcome was ICU mortality; secondary outcomes were in-hospital and 28-day mortality. Results The MIMIC-IV ICU cohort included 644 patients, with 71 ICU deaths, 102 in-hospital deaths, and 133 deaths within 28 days. SOFA-2 showed good discrimination for ICU mortality (AUROC, 0.834; 95% CI, 0.777–0.883), but its performance was similar to SOFA (AUROC, 0.838; 95% CI, 0.784–0.886; difference, − 0.005; 95% CI, − 0.020 to 0.010; P = 0.514). For in-hospital mortality, AUROCs were 0.786 for SOFA-2 and 0.784 for SOFA. For 28-day mortality, AUROCs were 0.760 and 0.756, respectively. Calibration, reclassification and decision-curve analyses did not show a clinically meaningful advantage for SOFA-2. ICU mortality increased across SOFA-2 strata, from 1.9% at scores 0–2 to 27.9% at scores ≥ 9. In eICU, SOFA-2 and SOFA again showed similar discrimination (AUROC, 0.833 vs 0.835), and mortality increased from 1.2% to 22.9% across the same score strata. Conclusions SOFA-2 stratified mortality risk in ICU patients with AC, but it did not outperform SOFA. These findings support SOFA-2 as a feasible disease-specific research measure, but they do not support replacing SOFA with SOFA-2 for clinical risk assessment in AC without further independent validation.