Comorbidities Matter as Distressed Communities Index Fails to Predict Mortality in Necrotizing Soft Tissue Infection

Abstract

Background: Necrotizing soft tissue infections (NSTIs) are life-threatening infections requiring prompt intervention. The Distressed Communities Index (DCI) is a comprehensive ranking of socioeconomic well-being based on zip code. We sought to identify the role of DCI in predicting mortality in NSTI, because it remains unknown. Patients and Methods: A retrospective, single-institution analysis of patients diagnosed with NSTI (2011-2020) requiring surgical intervention. The DCI is a composite score based on community-level factors: unemployment, education level, poverty rate, median income, business growth, and housing vacancies. The DCI scores were matched to the patient's zip code and stratification was performed using quintiles. Parametric and non-parametric analyses were performed to evaluate both the demographic and clinical characteristics. Multivariable regression analyses were performed to identify independent variables associated with outcomes. Results: Six hundred twenty patients met inclusion criteria. Ninety-day mortality was 12.4% (n = 77). Patients who died were more likely to be female (58.4%), older (median age 60.5 ± 11.3 years), have a body mass index (BMI) ≥30 (61.5%), have a higher Charlson Comorbidity Index (3; interquartile range [IQR], 2-7). After regression analysis, neither the composite DCI by quintile, nor the individual component scores, were found to correlate with mortality. Interestingly, underlying heart disease, hepatic dysfunction, and renal disease at baseline were found to significantly correlate with mortality from NSTI with p values <0.05. Conclusions: Socioeconomic status and insurance payer are championed for inclusion when constructing risk models, evaluating resource utilization, comparing hospitals, and determining patient management. The severity of community distress measured by DCI did not correlate with mortality for NSTI, despite contrasting evidence in other diseases. This finding is likely caused by a combination of both individual and community-level resources. This is highlighted by the recognition that comorbidities did correlate with mortality. The absence of DCI-related associations observed in this study warrants further investigation, as do mechanisms for the prevention of further organ dysfunction.

Keywords: Distressed Communities Index; comorbidities; mortality; necrotizing soft tissue infection; socioeconomic.