Assessment and Comparison of Performance of ABCD-10 and SCORTEN in Prognostication of Epidermal Necrolysis

Importance Epidermal necrolysis is a rare severe cutaneous drug reaction associated with high mortality. The ABCD-10 score (age, bicarbonate, cancer, dialysis, 10% body surface area), a new prognostic score for mortality in epidermal necrolysis, was recently developed and validated in the US. However, to our knowledge, it remains to be externally validated in other cohorts. Objective To assess ABCD-10 among patients in a contemporary Asian cohort and compare its performance with the Score of Toxic Epidermal Necrosis (SCORTEN) and study the associations of time and immunomodulatory therapy with the performance of ABCD-10 and SCORTEN. Design, Setting, and Participants This retrospective cohort study was conducted over a 17-year period from January 2003 to March 2019 and included 196 patients with epidermal necrolysis who were recruited from Singapore General Hospital, the national referral center for epidermal necrolysis. Main Outcomes and Measures In-hospital mortality. Discrimination and calibration of each risk score were assessed and compared using the area under the receiver operating characteristic curve and calibration plot, respectively. Results Among 196 patients (median [interquartile range] age, 56 [42-70] years; 116 women [59.2%]), 45 (23.0%) did not survive to discharge. All risk factors in ABCD-10 were significantly associated with in-hospital mortality. However, dialysis before admission, the most heavily weighted factor in ABCD-10, performed weaker in this cohort (odds ratio, 3.7; 95% CI, 1.0-13.2, P = .04). Although the discrimination of ABCD-10 and SCORTEN did not differ (area under the curve: ABCD-10, 0.78; 95% CI, 0.72-0.85; vs SCORTEN, 0.77; 95% CI, 0.69-0.84; P = .53), the calibration of ABCD-10 was poorer compared with SCORTEN. From graphical analysis of the calibration plots, ABCD-10 showed mortality underestimation at lower score ranges and overestimation at higher score ranges. By contrast, SCORTEN was generally well calibrated, although at higher score ranges mortality may be overestimated. Assessment of calibration plots showed that there was increasing overestimation of mortality by SCORTEN during the later period or when immunomodulatory therapy was used compared with patients treated with supportive care alone. Calibration of ABCD-10 remained poor even during the later period or among patients treated with immunomodulatory therapy. Conclusions and Relevance In this cohort of patients, the performance of SCORTEN was superior to ABCD-10 in mortality prognostication in epidermal necrolysis. However, it did display time-associated deterioration in calibration leading to overestimation of mortality risk. Future studies may consider revising the existing SCORTEN given its current good discrimination. Question Does the ABCD-10 score (age, bicarbonate, cancer, dialysis, 10% body surface area), a new risk prediction model for in-hospital mortality in epidermal necrolysis, show better performance than the Score of Toxic Epidermal Necrolysis (SCORTEN)? Findings In this cohort study of 196 patients in an Asian national referral center for epidermal necrolysis, while discrimination of ABCD-10 did not differ from SCORTEN, ABCD-10 was shown to have poorer calibration in prognostication of in-hospital mortality. Dialysis before admission, which weighted the most heavily in ABCD-10, was a weaker predictor in this cohort. Meaning The findings of this study suggest that SCORTEN should be used for mortality prognostication in epidermal necrolysis instead of ABCD-10. This cohort study assesses the performance of ABCD-10 compared with SCORTEN for patients with epidermal necrolysis in Singapore.