Eosinopenia and Neutrophil to Lymphocyte Ratio in COVID-19 Infection, a Prospective Study from Tertiary Care Hospital in Pakistan

OBJECTIVE: To assess eosinopenia and neutrophil to lymphocyte ratio in patients admitted with COVID-19 infection and correlate with pneumonia severity. METHODOLOGY: This prospective observational study was conducted at Covid HDU of Dr.Ruth KM Pfau Civil Hospital, Karachi, from October - December 2021. Data was collected using convenience sampling. The inclusion criteria were patients between 18-70 years with symptoms suggestive of COVID-19 and positive RT-PCR. Patients with negative RT-PCR with alternate diagnosis, history of using a corticosteroid, pancreatic or esophageal malignancy, and recent burn were excluded. Data analysis was done using SPSS version 23. RESULTS: Out of 141 patients, 66(46%) were classified as non-severe covid and 75(53.9%) as severe covid pneumonia. A significant association between eosinopenia and COVID severity was observed. The NLR was significantly increased in severe COVID patients compared to non- severe patients. Similarly, eosinophil was decreased considerably in severe covid compared to non-severe patients (p-value<0.05). The area under the eosinopenia ROC curve is 0.71 and 0.69 on days 7 and 3, respectively. Thus, eosinopenia on day 7 was fair in predicting severe COVID- 19 pneumonia compared with increased NLR, which was poor in predicting severe COVID-19. Using the area under the ROC curve, an eosinophil count cutoff of < 100 cells/mm3 produced a sensitivity of 75% for severe COVID-19 pneumonia. CONCLUSION: Eosinopenia and elevated NLR were found with increased frequency in patients with severe COVID-19 pneumonia; however, persistent eosinopenia was a better marker than NLR in predicting COVID-19 infection severity. KEYWORDS: Eosinopenia, Neutrophil to lymphocyte ratio, Covid-19, Pneumonia