The prognostic significance of neutrophil-lymphocyte ratio (NLR) in patients with COVID-19

ABSTRACT

INTRODUCTION: Neutrophil lymphocyte ratio (NLR) is elevated in response to stressful stimuli and has been shown to be associated with poor prognosis in both benign & malignant disorders. Literature regarding NLR as a prognostic marker in COVID19 are limited. Our study was aimed to investigate the relationship between NLR & survival outcomes in patients hospitalized with Coronavirus disease 2019 (COVID19). METHODS: Ours was a single center, retrospective observational study, which included 472 nasopharyngeal swab SARS-CoV-2 RT-PCR positive patients. NLR was derived from the admission complete blood count & was divided into 5 sub-groups as (0-0.99, 1-2.99, 3-9.99, 10-19.99, >20). Demographics, comorbid conditions, and outcomes such as need for mechanical ventilation, length of stay and inpatient mortality were assessed. Statistics were performed using STATA. Significance was assigned at p<0.05. RESULTS: The mean age was 71.16 years in NLR >10 group as compared to 60.3 years in patients with normal NLR 1-2.99. Male patients were found to have much higher NLR than females (65.12% vs 34.88% in NLR 10-19.99, 64.86% vs 35.14% in NLR>20;p-value 0.05). Among comorbidities, COPD patients were found to have higher NLR (18.92% of NLR>20 vs 10.71% of NLR 1-2.99;p-value0.02). Rate of endotracheal intubation and need for mechanical ventilation was significantly higher with increasing NLR (0% vs 7% vs 14% vs 17% vs 32%;p-value 0.03). Inpatient mortality was significantly higher in patients who had NLR>20 (70.27% of NLR>20 vs 16.07% of NLR 1-3 p-value <0.0001). On multivariate regression, patients with NLR>20 had 4 times higher odds of mortality;however, the p-value was not significant (4.07±2.78 p-value 0.175). CONCLUSIONS: Increasing NLR in COVID19 patients is associated with increased ICU admission, intubation & inpatient mortality. Further studies are warranted to establish NLR, which is readily available & inexpensive, as a potential prognostic indicator in COIVD19 patients.