[Neutrophil-lymphocyte ratio as predictor of mortality in patients with necrotizing fasciitis].

Background: Necrotizing fasciitis (NF) can affect any soft tissue and skin of the body. Its progression is rapid and it is associated with a high mortality rate. Therefore, the search for easily accessible and low-cost biomarkers that could predict the prognosis of patients with NF is necessary.

Objective: To evaluate the role of neutrophil-lymphocyte ratio (NLR) as a predictor of mortality in patients with NF.

Material and methods: Observational, cross-sectional, retrospective and analytical study of patients admitted between April and October 2020 in a tertiary-care hospital. The statistical tests used for the comparison of variables between the study groups were chi-square, Fisher's exact, Student's t and Mann-Whitney U. A receiver operating characteristic (ROC) curve was performed to determine the accuracy of NLR in predicting mortality in patients with NF.

Results: A total of 25 patients were included and stratified into non-survivors and survivors. The non-survivor group had an elevated NLR value compared to survivors (15.57 [13.75] vs. 7.91 [4.13]; p = 0.065). The NLR had an area under the curve (AUC) of 0.729 (95% confidence interval [95% CI] 0.516-0.886; p = 0.044), sensitivity of 77.78% (40-97.2), and specificity of 75% (47.6-92.7). The optimal cut-off point obtained for NLR was > 9.21.

Conclusions: An NLR value > 9.21 could be a predictor of mortality in patients with NF.