What Demographic and Clinical Factors Are Associated with In-hospital Mortality in Patients with Necrotizing Fasciitis?

BACKGROUND: Necrotizing fasciitis is a rare infection with rapid deterioration and a high mortality rate. Factors associated with in-hospital mortality have not been thoroughly evaluated. Although predictive models identifying the diagnosis of necrotizing fasciitis have been described (such as the Laboratory Risk Indicator for Necrotizing Fasciitis [LRINEC]), their use in predicting mortality is limited.

QUESTIONS/PURPOSES: (1) What demographic factors are associated with in-hospital mortality in patients with necrotizing fasciitis? (2) What clinical factors are associated with in-hospital mortality? (3) What laboratory values are associated with in-hospital mortality? (4) Is the LRINEC score useful in predicting mortality?

METHODS: We retrospectively studied all patients with necrotizing fasciitis at our tertiary care institution during a 10-year period. In all, 134 patients were identified; after filtering out patients with missing data (seven) and those without histologically confirmed necrotizing fasciitis (12), 115 patients remained. These patients were treated with early-initiation antibiotic therapy and aggressive surgical intervention once the diagnosis was suspected. Demographic data, clinical features, laboratory results, and treatment variables were identified. The median age was 56 years and 42% of patients were female. Of the 115 patients analyzed, 15% (17) died in the hospital. Univariate and receiver operating characteristic analyses were performed due to the low number of mortality events seen in this cohort.

RESULTS: The demographic factors associated with in-hospital mortality were older age (median: 64 years for nonsurvivors [interquartile range (IQR) 57-79] versus 55 years for survivors [IQR 45-63]; p = 0.002), coronary artery disease (odds ratio 4.56 [95% confidence interval (CI) 1.51 to 14]; p = 0.008), chronic kidney disease (OR 4.92 [95% CI 1.62 to 15]; p = 0.006), and transfer from an outside hospital (OR 3.47 [95% CI 1.19 to 10]; p = 0.02). The presenting clinical characteristics associated with in-hospital mortality were positive initial blood culture results (OR 4.76 [95% CI 1.59 to 15]; p = 0.01), lactic acidosis (OR 4.33 [95% CI 1.42 to 16]; p = 0.02), and multiple organ dysfunction syndrome (OR 6.37 [95% CI 2.05 to 20]; p = 0.002). Laboratory values at initial presentation that were associated with in-hospital mortality were platelet count (difference of medians -136 [95% CI -203 to -70]; p < 0.001), serum pH (difference of medians -0.13 [95% CI -0.21 to -0.03]; p = 0.02), serum lactate (difference of medians 0.90 [95% CI 0.40 to 4.80]; p < 0.001), serum creatinine (difference of medians 1.93 [95% CI 0.65 to 3.44]; p < 0.001), partial thromboplastin time (difference of medians 8.30 [95% CI 1.85 to 13]; p = 0.03), and international normalized ratio (difference of medians 0.1 [95% CI 0.0 to 0.5]; p = 0.004). The LRINEC score was a poor predictor of mortality with an area under the receiver operating characteristics curve of 0.56 [95% CI 0.45-0.67].

CONCLUSIONS: Factors aiding clinical recognition of necrotizing fasciitis are not consistently helpful in predicting mortality of this infection. Identifying patients with potentially compromised organ function should lead to aggressive and expedited measures for diagnosis and treatment. Future multicenter studies with larger populations and a standardized algorithm of treatment triggered by high clinical suspicion can be used to validate these findings to better help prognosticate this potentially fatal diagnosis.Level of Evidence Level III, therapeutic study.