The Impact of Sarcopenia on Mortality in Patients With Necrotizing Soft Tissue Infections

Abstract

Purpose: Necrotizing soft-tissue infections (NSTIs) are surgical emergencies associated with high morbidity and mortality. Identifying risk factors for poor outcomes is a critical part of preoperative decision-making and counseling. Sarcopenia, the loss of lean muscle mass, has been associated with an increased risk of mortality and can be measured using cross-sectional imaging. Our aim was to determine the impact of sarcopenia on mortality in patients with NSTIs. Methods: This is a retrospective cohort study of NSTI patients admitted from 1995 to 2014 to two academic institutions. Average bilateral psoas muscle cross-sectional area at L4, normalized for height (Total Psoas Index [TPI]), was calculated using computed tomography. Sarcopenia was defined as TPI in the lowest sex-specific quartile. Primary outcome was in-hospital mortality. Multivariate logistic regression was performed to assess the association between sarcopenia and in-hospital mortality. Results: There were 115 patients with preoperative imaging, 61% males and a median age of 57 years (IQR 46.6-67.0). Overall in-hospital mortality was 12.1%. There was no significant difference in gender, body mass index, comorbidities, or American Society of Anesthesiologists classification. After multivariate analysis, sarcopenia was independently associated with increased in-hospital mortality (Odds ratio, 3.5; 95% Confidence Interval [CI], 1.05-11.8). Conclusions: Sarcopenia is associated with increased risk of in-hospital mortality in patients with necrotizing soft-tissue infections. Sarcopenia identifies patients with higher likelihoods of poor outcomes, which can possibly help surgeons in counseling their patients and families.