Identification of potentially modifiable factors to improve recognition and outcome of necrotizing soft-tissue infections

Background: Necrotizing soft-tissue infections (NSTIs) present a surgical emergency of increasing incidence, which is often misdiagnosed and associated with substantial mortality and morbidity. A retrospective multicenter (11 hospitals) cohort study was initiated to identify the early predictors of misdiagnosis, mortality, and morbidity (skin defect size and amputation). Methods: Patients of all ages who presented with symptoms and were admitted for acute treatment of NSTIs between January 2013 and December 2017 were included. Generalized estimating equation analysis was used to identify early predictors (available before or during the first debridement surgery), with a significance level of P < 0.05. Results: The median age of the cohort (N = 216) was 59.5 (interquartile range = 23.6) years, of which 138 patients (63.9%) were male. Necrotizing soft-tissue infections most frequently originated in the legs (31.0%) and anogenital area (30.5%). More than half of the patients (n = 114, 54.3%) were initially misdiagnosed. Thirty-day mortality was 22.9%. Amputation of an extremity was performed in 26 patients (12.5%). Misdiagnosis was more likely in patients with a higher Charlson Comorbidity Index (β = 0.20, P = 0.001), and less likely when symptoms started in the anogenital area (β = -1.20, P = 0.003). Besides the established risk factors for mortality (septic shock and age), misdiagnosis was identified as an independent predictor of 30-day mortality (β = 1.03, P = 0.01). The strongest predictors of the final skin defect size were septic shock (β = 2.88, P < 0.001) and a skin-sparing approach to debridement (β = -1.79, P = 0.002). Conclusion: Recognition of the disease is essential for the survival of patients affected by NSTI, as is adequate treatment of septic shock. The application of a skin-sparing approach to surgical debridement may decrease morbidity.