SCORTEN: A severity-of-illness score for toxic epidermal necrolysis

The mortality of toxic epidermal necrolysis is about 30%. Our purpose was t o develop and validate a specific severity-of-illness score for cases of to xic epidermal necrolysis admitted to a specialized unit and to compare it w ith the Simplified Acute Physiology Score and a burn scoring system. A samp le of 165 patients was used to develop the toxic epidermal necrolysis-speci fic severity-of-illness score and evaluate the other scores, a sample of 75 for validation. Model development used logistic regression equations that were translated into probability of hospital mortality; validation used mea sures of calibration and discrimination. We identified seven independent ri sk factors for death and constituted the toxic epidermal necrolysis-specifi c severity-of-illness score: age above 40 y, malignancy, tachycardia above 120 per min, initial percentage of epidermal detachment above 10%, serum ur ea above 10 mmol per liter, serum glucose above 14 mmol per liter, and bica rbonate below 20 mmol per liter. For each toxic epidermal necrolysis-specif ic severity-of-illness score point the odds ratio was 3.45 (confidence inte rval 2.26-5.25). Probability of death was: P(death) = e(logit)/1 + e(logit) with logit = -4.448 + 1.237 (toxic epidermal nec-rolysis-specific severity -of-illness score). Calibration demonstrated excellent agreement between ex pected (19.6%) and actual (20%) mortality; discrimination was also excellen t with a receiver operating characteristic area of 82%. The Simplified Acut e Physiology Score and the burn score were also associated with mortality. The discriminatory powers were poorer (receiver operating characteristic ar ea: 72 and 75%) and calibration of the Simplified Acute Physiology Score in dicated a poor agreement between expected (9.1%) and actual (26.7%) mortali ty. This study demonstrates that the risk of death of toxic epidermal necro lysis patients can be accurately predicted by the toxic epidermal necrolysi s-specific severity-of-illness score. The Simplified Acute Physiology Score and burn score appear to be less adequate.