Prognostication of the Outcomes in Patients on Mechanical Ventilation Due to Severe ARDS in COVID-19 Using Neutrophil to Lymphocyte Ratio (NLR) at Admission

ABSTRACT

Background: The neutrophil-to-lymphocyte ratio (NLR) has been used as a circulating biomarker to determine the prognosis of inflammatory reaction in many conditions. Inflammation has an important role in the progression of COVID-19. NLR has proved to be potentially useful in diagnosing and prognosis of COVID-19 patients. Aim: To determine whether NLR is useful for the prognostication of outcomes in patients on mechanical ventilation due to severe ARDS in COVID-19. Materials and methods: This is a prospective study in which patients of both genders between age 18 and 78 years with severe ARDS due to COVID-19 who required mechanical ventilation within 1st 3 days of admission were included. CBC was done on 1st day of admission for calculation of NLR. The outcome was defined as in-hospital mortality. Pregnant patients, patients on steroids, and immunosuppression therapy and immune-compromised patients were excluded from the study. Results: Statistical analysis was done using Mann-Whitney, Pearson, and Chi-Square tests. 135 patients who required mechanical ventilation within the first 3 days of admission were included. 34 (25.1%) patients were females and 101 (74.81%) patients were males. 49 (36.29%) patients survived and 88 (63.70%) patients died. The median of NLR in alive 11.10 (1.18-48) and dead 11.05 (1.55-48) was statistically insignificant (P value 0.71). The comparison of NLR in males (14.37 ± 10.51) and females (10.76 ± 5.74) was statistically significant (p = 0.05). The mortality in females was 70.58% whereas in males it was 61.38%. As per the Person correlation test, there is a negative correlation of NLR with age and gender to determine mortality. Conclusion: NLR is not a good biomarker to predict the outcomes of patients on mechanical ventilation due to severe ARDS in COVID-19 disease. Though the NLR values were lower in females, the mortality was higher in the female group.