Risk factors for mortality in the late amputation of necrotizing fasciitis: a retrospective study

BACKGROUND: Necrotizing fasciitis (NF) is a rapidly progressive infectious disease that primarily involves the fascia and subcutaneous tissue. If not promptly treated, it can lead to morbidity as well as mortality. It can affect any part of the body, most commonly the extremities. Early and aggressive surgical treatment is the proper way of management. The purpose of this study was to identify the risk factors for mortality in late amputation among NF patients that may be used in routine clinical practice to prevent mortality. METHODS: A retrospective cohort study of hospitalized patients with NF was conducted in a tertiary teaching hospital in Taiwan between March 2015 and March 2018. All collected data were statistically analyzed. RESULTS: A total of 582 patients with NF were included; 35 of them had undergone amputation (7 primary and 28 late amputations), with a 6% amputation rate. Thirteen amputated patients still died eventually (all in the late amputation group). Significant risk factors for mortality identified in the late amputation group included hemorrhagic bullae (p = 0.001, OR 4.7, 95% confidence interval (CI) 2.68–8.69), peripheral vascular disease (p < 0.001, OR 3.2, 95% CI 1.12–10.58), bacteremia (p = 0.021, OR 2.87, 95% CI 2.07–5.96), and Laboratory Risk Indicator of Necrotizing Fasciitis (LRINEC) score > 8 (p < 0.001, OR 1.97, 95% CI 1.28–4.61). Vibrio vulnificus was the main causative organism based on our study, but the microbiology results showed no significant correlation. CONCLUSION: NF patients with hemorrhagic bullae, comorbidity with peripheral vascular disease, presence of bacteremia, or LRINEC score > 8 should receive early and primary amputation in order to prevent mortality.