Introduction:
Novel Coronavirus disease (COVID-19) is a new infectious agent of the respiratory tract characterized by a severe acute respiratory syndrome (SARS). SARS-CoV-2 started in Wuhan, China in December 2019 and quickly evolved into a rapidly spreading pandemic1. Because of its high infectivity and mortality, it is a serious public health threat2.
Although most patients are asymptomatic or have mild symptoms and a good prognosis, COVID-19 can progress to more severe illnesses, including pneumonia, acute respiratory distress syndrome, multiple organ failure, or even death3,4. The aim of successful treatment is reduction of complications and mortality. Basic disease treatment is also needed to prevent secondary infection.
For this disease, there are limited data with regard to the clinical characteristics of the patients and prognostic factors5. Chronic diseases and old age have been assumed to be associated with adverse disease prognosis. Little attention has been given to the role of smoking in the transmission of SARS-CoV2. Smokers contract more respiratory infections including colds (commonly rhinoviruses), than non-smokers. Smokers also develop influenza twice as often and show increased rates of bacterial pneumonia and tuberculosis. The damage caused to the lungs by smoking makes these patients more susceptible to pulmonary infections, both bacterial and viral6.
There are two opposing opinions about the effect of smoking on COVID-19’s severity. It has recently been reported that ACE2 gene expression, which is known to be a cellular entry gateway for SARS-CoV-2, is higher in smokers. This expression is also the upregulation associated with smoking, this suggests that smoking contributes to a higher number of viral receptors and may support the findings of the recent case series research7,8. However, the second opinion is that smoking prevents downregulation of angiotensin-converting enzyme 2 (ACE2) and that this downregulation is harmful due to uncontrolled ACE2 and angiotensin II activity9. It has been observed that decreased ACE2 availability contributes to lung injury and increases the chance of development of acute respiratory distress syndrome (ARDS)9.
Therefore, it is very important to find the related factors of disease severity in clinical practice. In this study, we compared the clinic and laboratory findings and computed tomography (CT) features of 223 ordinary COVID-19 cases.