Contemporary trends in necrotizing soft-tissue infections in the United States

Abstract

Background: Necrotizing soft-tissue infections (NSTI) are rare, potentially fatal, operative emergencies. We studied a national cohort of patients to determine recent trends in incidence, treatment, and outcomes for NSTI.

Methods: We queried the Nationwide Inpatient Sample (1998-2010) for patients with a primary diagnosis of NSTI. Temporal trends in patient characteristics, treatment (debridement, amputation, hyperbaric oxygen therapy [HBOT]), and outcomes were determined with Cochran-Armitage trend tests and linear regression. To account for trends in case mix (age, sex, race, insurance, Elixhauser index) or receipt of HBOT on outcomes, multivariable analyses were conducted to determine the independent effect of year of treatment on mortality, any major complication, and hospital length of stay (LOS) for NSTI.

Results: We identified 56,527 weighted NSTI admissions, with an incidence ranging from approximately 3,800-5,800 cases annually. The number of cases peaked in 2004 and then decreased between 1998 and 2010 (P < .0001). The percentage of female patients decreased slightly over time (38.6-34.1%, P < .0001). Patients were increasingly in the 18- to 34-year-old (8.8-14.6%, P < .0001) and 50- to 64-year-old age groups (33.2-43.5, P < .0001), Hispanic (6.8-10.5%, P < .0001), obese (8.9-24.6%, P < .0001), and admitted with >3 comorbidities (14.5-39.7%, P < .0001). The percentage of patients requiring only one operative debridement increased somewhat (43.2-46.2%, P < .0001), whereas the use of HBOT was rare and decreasing (1.6-0.8%, P < .0001). The percentage of patients requiring operative wound closure decreased somewhat (23.5-20.8%, P < .0001). Although major complication rates increased (30.9-48.2%, P < .0001), hospital LOS remained stable (18-19 days) and mortality decreased (9.0-4.9%, P < .0001) on univariate analyses. On multivariable analyses each 1-year incremental increase in year was associated with a 5% increased odds of complication (odds ratio 1.05), 0.4 times decrease in hospital LOS (coefficient -0.41), and 11% decreased odds of mortality (odds ratio 0.89).

Conclusion: There were potentially important national trends in patient characteristics and treatment patterns for NSTI between 1998 and 2010. Importantly, though patient acuity worsened and complication rates increased, but LOS remained relatively stable and mortality decreased. Improvements in early diagnosis, wound care, and critical care delivery may be the cause.

Figure 1

Trends in Elixhauser > 3, incidence of any major complication, and mortality among NSTI patients 1998–2010 (N=56,527)