Obesity Is Not an Independent Predictor of Necrotizing Soft Tissue Infection Outcomes

A Cross-Sectional Analysis of Pediatric Necrotizing Soft Tissue Infection Cases and Racial Disparities From the 2016 to 2020 National Inpatient Sample

INTRODUCTION

The incidence, treatment, and outcomes of necrotizing soft tissue infections (NSTIs) and associated racial disparities have been described in adults, but research in the pediatric population is limited. The purpose of this study is to provide a nationally representative characterization of pediatric NSTI and determine the presence of any racial disparities.

METHODS

The National Inpatient Sample was analyzed from 2016 through 2020. Patients aged less than 20 y with a diagnosis of necrotizing fasciitis, Fournier's gangrene, or gas gangrene (based on International Classification of Diseases, Tenth Revision, Clinical Modification codes) were included for analysis.

RESULTS

A total of 355 patients were identified. Black and Hispanic patients accounted for the most admissions in 2016 and 2018, respectively (P = 0.024). Compared to White patients, more Black patients were insured by Medicaid (P = 0.037) and were in the first zip code-based income quartile (P = 0.005). The leading infection overall was necrotizing fasciitis and most patients (81.7%) underwent a surgical procedure by the first calendar day after admission. Although the proportion of Black patients undergoing subcutaneous tissue and fascia excisions was more than that of White patients (P = 0.005), there were no significant differences by race in the time to first procedure, the total number of procedures, or number of postoperative complications. Our amputation and mortality rates were low and unreportable, but there were no differences by race.

CONCLUSIONS

NSTI is rare in the pediatric population and mortality is low. Black patients are disproportionately diagnosed, but these disparities do not extend to disease treatment or outcomes.

Time Is Fascia: Laboratory and Anamnestic Risk Indicators for Necrotizing Fasciitis

Background: Necrotizing fasciitis is a potentially fatal soft tissue infection in which the timing of surgical intervention significantly affects clinical outcome. The Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score, the Site other than the lower limb, Immunosuppression, Age <60 years, Renal impairment (creatinine >141), and Inflammatory markers (CRP ≥150, WCC >25) (SIARI) score, and procalcitonin levels are intended to aid in the decision-making process to differentiate between necrotizing fasciitis and soft tissue infections. Methods: A retrospective analysis of cases of necrotizing fasciitis and soft tissue infections treated at Klinikum Nürnberg was performed. The two scores as well as procalcitonin levels were tested for their diagnostic value and a new score, the Laboratory and Anamnestic Risk Indicator for Necrotizing Fasciitis (LARINF), was created based on the results. Results: Procalcitonin, LRINEC score, and SIARI score showed insufficient discriminatory ability in our study. The newly created LARINF score combined laboratory parameters of the LRINEC score (hemoglobin and C-reactive protein) with procalcitonin and three comorbidities, resulting in a sensitivity of 84% and a specificity of 75% and the highest area under the receiver operating characteristic (ROC) curve of 0.83. Conclusions: The LARINF score is a novel decision-supporting tool. The decision, in which cases surgical exploration should be initiated, remains a clinical one. However, the score seems to provide an improved basis for identifying a rare clinical picture.

Characterization of Necrotizing Soft Tissue Infections in Obese and Non-Obese Patients

Background: The impact of obesity on the pathogenesis and prognosis of necrotizing soft tissue infections (NSTIs) is unclear. The goal of this study was to characterize differences in NSTI presentation and outcomes by obesity status. Patients and Methods: A retrospective analysis of institutional data for patients diagnosed with NSTIs were identified (n = 619; 2011-2020). Patients were divided based on obesity (body mass index [BMI] ≥ 30 kg/m²) and non-obese (BMI <30 kg/m²). Primary outcomes included NSTI location, micro-organisms, and index hospitalization data. Multiple logistic regression was used to model predictors of in-hospital and 90-day mortality. Results: The obese cohort (n = 390; 63%) had higher rates of congestive heart failure and type 2 diabetes mellitus. There were no differences in length of stay, mortality, or discharge disposition between groups. A higher rate of respiratory failure was observed in the obese versus non-obese group (36.7% vs. 20.9%; p < 0.0005). The obese cohort was associated with perineal (40.8% vs. 27.0%) and torso NSTIs (20.9% vs. 15.8%; p < 0.005) but reduced staphylococcal (19.2% vs. 27.4%; p = 0.02) and group A streptococcal (2.6% vs. 6.5%; p = 0.03) infections, and increased polymicrobial infections. Class 2 obesity was a negative predictor for in-hospital mortality (odds ratio [OR], 0.1; 95% confidence interval [CI], 0.03-0.5) and 90-day mortality (OR, 0.3; 95% CI, 0.1-0.8), when adjusting for demographic data, type of infection, and baseline comorbidities. Conclusions: Necrotizing soft tissue infections in obesity may present with unique distributions and microbial characteristics. Class 2 obesity may exhibit a survival benefit compared with non-obese patients, suggestive of an obesity paradox.