Impact of Comorbidities on the Cause of Death by Necrotizing Soft Tissue Infections

Background: The aim of this study was to identify the cause of death in patients with necrotizing soft tissue infections (NSTIs) stratified by patient's pre-existing comorbidities (American Society of Anesthesiologists [ASA] classification 3/4 vs. ASA 1/2). Differences in clinical presentation, mortality rate, and factors associated with mortality between those two comorbidity groups were investigated.Patients and Methods: A retrospective multicenter study of patients with NSTIs between 2010 and 2020 was conducted. The primary outcome was the cause of death within the first 30 days. Furthermore, factors associated with mortality were identified. All analysis were stratified by severity of comorbidities (ASA 1/2 or ASA 3/4).Results: Of the 187 patients, 39 patients (21%) died within 30 days. American Society of Anesthesiologists 1/2 patients (overall mortality rate, 11%) died more often as direct result of the infection compared with ASA 3/4 patients (overall mortality rate, 33%) (ASA 1/2 group: 92% vs. ASA 3/4 group: 48%; p = 0.013). American Society of Anesthesiologists 3/4 patients died more often due to withdrawal of life-sustaining therapies based on assumed poor outcome after severe critical illness (ASA 1/2 group: 52% vs. ASA 3/4 group: 8%; p = 0.013).Conclusions: Mortality rates of patients with NSTIs varied from 11% in previously healthy patients to 33% in patients with multiple or severe comorbidities. The predominant cause of mortality was overwhelming infection and associated sepsis in healthy patients whereas in patients with multiple or severe pre-existing medical disease, death most often occurred after treatment limitations based on patient's wishes and prognosis.