Validation of the revised Baux score to predict mortality and formulation of a new model for burns mortality in Southeast Asian patients

• rBaux score correlates with mortality; LD50 at this study institution is 128. • TBSA, inhalation injury, heart failure, age predict mortality in multivariable model. • New burns model computes mortality probability; rBaux is a mortality risk index. The Revised Baux (rBaux) Score is used to predict mortality in burn patients but has reduced accuracy at extremes of age and does not account for comorbidities – factors relevant in an ageing population. This study assessed rBaux mortality thresholds for adult burn patients and formulates a burn mortality model for Southeast Asian patients that includes comorbidities. We conducted a retrospective analysis of 720 adult admissions to the Burns Unit at a Southeast Asian tertiary unit from January 2019 to December 2023. After excluding patients with Toxic Epidermal Necrolysis and Stevens-Johnson Syndrome, data from 649 patients on demographics, Total Body Surface Area (TBSA), inhalation injury, and Charlson Comorbidity Index (CCI) were analysed to identify mortality predictors, forming the basis of a new model. Of the 649 patients, 22 (3.39 %) died. Mortality was associated with higher age (median 53 vs. 42 years, p = 0.025), larger TBSA (73.5 % vs. 4.5 %, p < 0.001), inhalation injury (77.3 % vs. 33.5 %, p < 0.001), and higher CCI (2.5 vs. 0, p < 0.015). Predictive mortality thresholds were identified using rBaux, at 100 %, 75 %, and 50 % with scores of 159, 139, and 128, respectively. Multivariate analysis confirmed age, TBSA (in increments of 10 %)and Chronic Heart Failure (CHF) as independent predictors. Hence producing a new model with the following predictors: age, TBSA (in increments of 10 %), inhalation injury and Chronic Heart Failure (CHF). This new model had a Hosmer-Lemeshow. p-value of 0.77 and ROC area of 0.97, indicating excellent fit. This model improves burn mortality predictions for Southeast Asian adults by incorporating comorbidities like CHF. Although more complex than rBaux, it offers better patient management potential, meriting further regional validation.