Factors associated with in-hospital mortality in necrotising soft tissue infections. a multicentre retrospective cohort study

Purpose: Necrotising soft tissue infections (NSTIs) are rare but life-threatening conditions associated with high mortality rates. This multicentre study aimed to identify admission variables associated with in-hospital mortality. Methods: This retrospective study included adult patients with surgically confirmed NSTIs treated at four high-volume academic referral centres in Italy between 2010 and 2024. Demographic, clinical, physiological, and laboratory variables available at hospital admission were analysed. Categorical variables were compared between survivors and non-survivors using the chi-square test or Fisher's exact test, while quantitative variables were compared using the Student's t test or Mann-Whitney U test. Multivariable logistic regression analyses were performed to identify independent predictors of in-hospital mortality. Results were reported as ORs with 95%CI. A prognostic nomogram was developed from the final multivariable model, including variables independently associated with mortality. Results: A total of 379 patients were included. In-hospital mortality was 16.7%. In subgroup comparisons, mortality was 17.0% in necrotising fasciitis and 22.4% in Fournier's gangrene (P = 0.275). In the overall NSTI population, age (aOR 1.061, 95%CI 1.037-1.087) and serum creatinine at admission (aOR 1.301, 95%CI 1.040-1.629) were independently associated with mortality. In subgroup analyses, age (aOR 1.079, 95%CI 1.051-1.114) and chronic kidney disease (aOR 2.885, 95%CI 1.141-7.283) remained associated with mortality in limb necrotizing fasciitis, while only age (aOR 1.074, 95%CI 1.030-1.124) remained independently associated with mortality in Fournier's gangrene. However, subgroup analyses in necrotising fasciitis of the limbs and Fournier's gangrene were limited by low event rates and should be considered exploratory. The nomogram based on age and serum creatinine predicted in-hospital mortality (AUC 0.775, 95% CI 0.711-0.831), with good agreement between predicted and observed outcomes across risk levels. The FATAL-NSTI study identified age and serum creatinine at admission as key predictors of in-hospital mortality in necrotising soft tissue infections. A nomogram based on age and serum creatinine may support early risk stratification. #NecrotisingSoftTissuesInfections; #FournierGangrene; #NecrotisingFasciitis CONCLUSIONS: NSTIs remain associated with substantial mortality. Age was the most consistent predictor of in-hospital mortality.