Adding the Neutrophil Percentage-to-Albumin Ratio to the Severity-of-Illness Score for Toxic Epidermal Necrolysis for Prognostic Stratification in Adults with Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis.

Abstract

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) carry substantial mortality. The Severity-of-Illness Score for Toxic Epidermal Necrolysis (SCORTEN), the standard prognostic tool, was developed primarily for mortality prediction and may not fully capture broader poor outcomes. Composite inflammatory indices remain insufficiently evaluated. To compare the prognostic performance of three composite inflammatory indices-platelet-to-albumin ratio, C-reactive protein-to-lymphocyte ratio, and neutrophil percentage-to-albumin ratio (NPAR)-and to develop a risk stratification system. This retrospective cohort study included 122 adults with SJS/TEN. The primary outcome (termed poor outcome) was a composite of in-hospital mortality or intensive care unit admission. The inflammatory index independently associated with the outcome was combined with SCORTEN; model performance was assessed by discrimination, calibration, and clinical utility. Twenty patients (16.4%) experienced poor outcomes. Neutrophil percentage-to-albumin ratio (adjusted odds ratio = 1.25/1-unit increase; 95% CI, 1.06-1.47; P = .006) and SCORTEN (adjusted odds ratio = 4.91; 95% CI, 2.06-11.68; P < .001) independently predicted poor outcomes. The combined model showed good discrimination (area under the receiver operating characteristic curve [AUC] = 0.96, 95% CI, 0.93-0.99; optimism-corrected, 0.96) and calibration, modestly outperforming SCORTEN alone (Δ area under the curve = 0.04, P = .033). Using SCORTEN of 3 and greater and NPAR of 25.4 and greater, a three-tier system yielded event rates of 0 of 72 (0%), 3 of 24 (12.5%), and 17 of 26 (65.4%; P < .001 for trend) at an observed prevalence of 16.4%. Exploratory analysis suggested NPAR's predictive value diminished with increasing age (interaction P = .042). Adding NPAR to SCORTEN modestly improved discrimination for poor outcomes in SJS/TEN. External validation is needed before clinical adoption.