Incidence and Factors Associated With In-Hospital Mortality in Adult Patients With Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Nationwide Thai Cohort

BACKGROUND: Data on the incidence of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) in Thailand, where high-risk HLA alleles are prevalent, remain limited. Existing prognostic scores, including SCORTEN, may not capture all mortality determinants. OBJECTIVE: To estimate the incidence and identify factors associated with in-hospital mortality in adult patients with SJS/TEN in Thailand. METHODS: We conducted a retrospective cohort study using the nationwide Thai National Health Security Office database. Adults hospitalized with SJS/TEN were identified by International Statistical Classification of Diseases, 10th Revision codes between 2017 and 2024. Cox regression with time-varying coefficients was used to examine mortality risk factors. RESULTS: A total of 7237 incident cases were identified (83.9% SJS). Median age was 57 years (interquartile range 42-69), and 50.5% were female. The estimated incidence was 17.3/million (95% confidence interval [CI], 16.9-17.7), with a decline over time. In-hospital mortality was 4.1% for SJS and 15.5% for TEN. Independent factors associated with mortality beyond SCORTEN included invasive ventilation (hazard ratio [HR], 14.99; 95% CI, 7.08-31.75), liver disease (HR, 2.49; 95% CI, 1.13-5.46), renal disease (HR, 2.46; 95% CI, 1.96-3.04), and myocardial infarction (HR, 1.90; 95% CI, 1.19-3.04). Mortality risk also increased progressively with age (≥60 years) and varied by hospital type. Time-varying analysis showed that TEN, liver disease, and ventilation had the strongest early impact, whereas infections, particularly skin and soft tissue infections, emerged later (HR at day 28, 2.64; 95% CI, 1.37-5.09). CONCLUSIONS: The incidence of SJS/TEN in Thailand is high. Mortality is influenced by factors beyond established scoring systems, with effects that evolve over time.