Neutrophil to Lymphocyte Ratio (NLR) and Platelet to Lymphocyte Ratio (PLR) Versus Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) as Predictors of Outcome in Necrotising Fasciitis

Clinical and Laboratory Parameters for Differential Diagnosis of Necrotizing Faciitis and Cellulitis

ObjectiveS

Necrotizing fasciitis (NF) requires surgical intervention and has high morbidity and mortality. Furthermore, it can be confusing with some skin diseases such as cellulitis. We investigated the roles of clinical and laboratory parameters at the time of admission to the hospital in the differential diagnosis of NF and cellulitis patients.

Methods

Patients with cellulitis and NF located between the nipple level and the knee between January 2018 and January 2021 were included in our retrospective study. The fever, history, complete blood count results, blood biochemistry, C-reactive protein and procalcitonin values of the patients at the time of admission to the emergency department, length of hospital stay, mortality rates, and laboratory risk indicator for necrotizing fasciitis (LRINEC) scores were recorded and evaluated whether there was a difference in both patient groups.

Results

A total of 55 patients, including 26 patients in the NF group and 29 patients in the cellulite group, were included in the study. It was observed that patients with NF applied to the hospital statistically earlier, had higher leukocyte, platelet and neutrophil levels, had longer hospital stays and had higher mortality numbers.

Conclusion

In high leukocyte, platelet, and neutrophil levels in the case of cellulitis patients, the clinician should follow the patient's clinic course closely and keep NF in mind.

Is Neutrophil Lymphocyte Ratio, Platelet Lymphocyte Ratio or Red Blood Cell Distribution Width Associated with Risk of Mortality in Patients with Necrotizing Fasciitis

Purpose

Neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), and red blood cell distribution width (RDW) are novel biomarkers to indicate the inflammatory/immune response, and demonstrated to be effective in diagnosis, severity evaluation, and prognosis in a variety of chronic or acute conditions. This study aims to examine whether NLR, PLR and EDW are independently associated with mortality in necrotizing fasciitis (NF).

Methods

This study retrospectively enrolled patients diagnosed with NF and based on vitality status during hospitalization or within 30 days after discharge, survival and non-survival groups were defined. For distinctly comparing NLR, PLR, RDW and others, we enrolled the matched healthy controls of the same age and sex as the survivors of NF in a 1:1 ratio, which constituted the healthy control group. Comparisons were made between three groups. Variables tested with a P value < 0.10 were further entered into the multivariate logistic regression model to identify their independent association with mortality.

Results

A total of 281 subjects were included, including 127 healthy controls, 127 survivors, and 27 nonsurvivors with NF, respectively, indicating a mortality rate of 17.5%. ROC analysis showed that the optimal cutoff value for NLR, PLR and RDW was 11.1, 196.0 and 15.5%, respectively, and was tested as significant only for the first two (P < 0.001, = 0.004). Multivariate logistic analysis showed that NLR ≥ 11.1 (OR, 2.51) and PLR ≥ 196.0 (OR, 2.09) were independently associated with an increased risk of mortality in NF patients, together with age ((OR, 1.28, for each 10-year increment), comorbid diabetes mellitus (OR, 2.69) and liver disease (OR, 1.86), and elevated creatinine level (OR, 1.21 for each 10 umol/L elevation).

Conclusion

Elevated NLR and PLR are significant and independent predictors of mortality and can be considered for use when evaluating patients at risk of mortality.

Measures of Admission Immunocoagulopathy as an Indicator for In-Hospital Mortality in Patients with Necrotizing Fasciitis: A Retrospective Study

Necrotizing fasciitis is a rapidly progressive infection with a high mortality rate. Pathogens evade the host containment and bactericidal mechanisms by hijacking the coagulation and inflammation signaling pathways, leading to their rapid dissemination, thrombosis, organ dysfunction, and death. This study examines the hypothesis that measures of immunocoagulopathy upon admission could aid in the identification of patients with necrotizing fasciitis at high risk for in-hospital mortality.

Methods

Demographic data, infection characteristics, and laboratory values from 389 confirmed necrotizing fasciitis cases from a single institution were analyzed. A multivariable logistic regression model was built on admission immunocoagulopathy measures (absolute neutrophil, absolute lymphocyte, and platelet counts) and patient age to predict in-hospital mortality.

Results

The overall in-hospital mortality rate was 19.8% for the 389 cases and 14.6% for the 261 cases with complete measures of immunocoagulopathy on admission. A multivariable logistic regression model indicated that platelet count was the most important predictor of mortality, followed by age and absolute neutrophil count. Greater age, higher neutrophil count, and lower platelet count led to significantly higher risk of mortality. The model discriminated well between survivors and non-survivors, with an overfitting-corrected C-index of 0.806.

Conclusions

This study determined that measures of immunocoagulopathy and patient age at admission effectively prognosticated the in-hospital mortality risk of patients with necrotizing fasciitis. Given the accessibility of neutrophil-to-lymphocyte ratio and platelet count measurements determined from a simple complete blood-cell count with differential, future prospective studies examining the utility of these measures are warranted.

Level of Evidence

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Precritical abnormalities in routine blood parameters in necrotizing fasciitis

Necrotizing fasciitis is a rare and severe infectious disease that is often fatal and is characterized by the extensive necrosis of subcutaneous tissue and fascial planes. A number of clinical parameters have been intensively investigated to diagnose and assess the severity and prognosis of necrotizing fasciitis. Since it currently remains unclear whether these parameters are also abnormal before disease onset, the present study investigated this issue. We retrospectively recruited 38 patients, including 12 and 26 patients with necrotizing fasciitis and cellulitis, respectively. The results of routine blood examinations were collected at disease onset and also at baseline, which was defined as the time point before disease onset. No significant differences were observed in age or sex between the necrotizing fasciitis and cellulitis groups. However, significant differences were noted in the levels of hemoglobin, lymphocyte count, platelet count, neutrophil-to-lymphocyte ratio, sodium, creatinine, albumin, D-dimer, and Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) score at disease onset. Significant differences were also observed in the levels of hemoglobin, lymphocyte count, monocyte count, platelet count, creatinine, D-dimer, and LRINEC score at baseline. Hemoglobin, platelet count, C-reactive protein, creatinine, albumin, and D-dimer levels were already abnormal at baseline in the necrotizing fasciitis group. In conclusion, the present results revealed precritical abnormalities in routine blood parameters in patients with necrotizing fasciitis. Therefore, individuals predisposed to necrotizing soft tissue infection may be identified prior to disease onset.