Outcomes of Patients with Necrotizing Soft Tissue Infections: A Propensity-Matched Analysis Using the National Inpatient Sample

Background: Necrotizing soft tissue infections (NSTIs) are severe, rapidly spreading infections with high morbidity and mortality. Attempts to identify risk factors for mortality and morbidity have produced variable results. We hope to determine which factors across the NSTI population impact mortality, morbidities, and discharge disposition.Patients and Methods: Retrospective data from the National Inpatient Sample from 2012-2018 of patients with primary diagnosis of NSTI (gas gangrene, necrotizing faciitis, cutaneous gangrene, or Fournier gangrene) were identified for analysis. A 1:4 greedy match was performed and risk factors for in-hospital mortality and discharge disposition were examined. Continuous variables were assessed using t-tests and Wilcoxon rank sum tests. Categorical variables were assessed using chi(2) and Fisher exact tests. Statistical significance was defined as p < 0.05.Results: A total of 6,608 patients were identified. Weighted, this represents 33,040 patients; 32,390 are in the no-mortality cohort and 650 in the mortality cohort. Advanced age group was a risk factor for both in-hospital mortality and morbidity, but not for discharge to a skilled nursing or rehabilitation facility. Having two or more comorbidities was a risk factor for mortality, morbidity, and discharge to skilled nursing or rehabilitation facility. Cancer, liver disease, and kidney disease were predictors of in-hospital mortality. Diabetes mellitus and kidney disease were predictors of experiencing an in-hospital complication. Diabetes mellitus, heart disease, and kidney disease were predictors for discharge to skilled nursing or rehabilitation facility.Conclusions: Necrotizing soft tissue infections are associated with substantial morbidity and mortality. Identifying patients at higher risk for mortality, morbidity, and higher level of care at discharge can help providers properly allocate resources to improve patient outcomes and reduce the financial burden on patients and healthcare facilities. Special attention should be paid to those with existing or acute kidney dysfunction because this was the only comorbidity associated with increased risk mortality, morbidity, and discharge to higher level of care.