1 INTRODUCTION
The new coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a highly communicable infectious disease. It has rapidly and widely spread worldwide,1 and was declared a pandemic in March 2020 by World Health Organization.2 As of 27th August 2020, the cumulative number of confirmed cases in Pakistan is 294,193 with 8,987 active cases and 6,267 deaths.3
Despite significant advancements in medicine and science, we are still in the age of infancy regarding COVID-19 infection and its management. COVID-19 infection can be categorized as asymptomatic, mild, moderate, or severe disease. Moderate and severe COVID-19 infections have been associated with long hospital stays, difficult clinical management and high mortality rate.4 Clinically, if early warning signs of severe COVID-19 infection can be identified, timely intervention and treatment may help reduce the mortality, improve the cure rate, shorten the hospital stay and reduce the consumption of resources.
Different immunity parameters in the human body have been identified to combat the disease.5,6 These tests are often expensive and time delay occurs in the results of these tests, jeopardizing the patient’s treatment. Therefore, we ought to have a clinical indicator or marker that is inexpensive, has a rapid turnaround time, and is simultaneously specific and sensitive. One such marker is a complete blood count (CBC) profile, out of which neutrophils and lymphocytes are especially important. The neutrophils are increased in bacterial infection, and lymphocytes are reduced during viremia. Examining these two parameters can greatly help assess the COVID-19 infection.
A recent systematic review and metanalysis by Feng et al.regarding immune-inflammatory parameters in COVID-19 infection concluded that neutrophil/lymphocyte ratio (NLR) is associated with the progression of the infection and can be utilized by the physicians to identify high risk or deteriorating patients at an early stage.7 Several other studies have reported their findings that NLR can be used as an early warning signal of severe COVID-19 infection,8 and cohnsidered as an independent marker for poor clinical outcomes and mortality in COVID-19 infection.9-13 However, the majority of these studies have been reported from China and some from European countries. To our knowledge, no study has been conducted in this regard in the South-Asian population. Our study aimed to prospectively analyze the clinical data of COVID-19 patients admitted to the high dependency unit/intensive care unit (HDU/ICU) at District Headquarter (DHQ), Faisalabad (Pakistan) in order to determine the risk factors and markers, with particular focus on NLR, associated with severity of COVID-19 infection in the South-Asian population.