Background: The coronavirus disease ۲۰۱۹ (COVID-۱۹) is a newborn virus that has become an emergency since December ۲۰۱۹. A severe form of this disease is accompanied by intensive care unit (ICU) admission and death. The
COVID-۱۹ pandemic is still occurring in several countries; however, few facts are available about the disease. Risk factors and protective factors of this disease are still unknown. We know that smoking is a risk factor for several respiratory infections. However, considering some previous studies and nicotine’s anti-inflammatory mechanism, a smoking paradox in
COVID-۱۹ still persists as an obscure issue. Thus, we decided to evaluate the association between smoking and
COVID-۱۹ disease.Materials and Methods: In this study, sampling was performed simply and randomly from all admitted
COVID-۱۹ patients in ۲۰۲۰-۲۰۲۱. This is a retrograde case-control study, and ۹۲
COVID-۱۹ patients with a history of smoking were enrolled in the case group, and ۹۲
COVID-۱۹ patients without any smoking history were selected for the control group. Data were collected through a checklist. In this checklist, information such as the patient’s age, gender, and medical condition was recorded. In the end, collected data were analyzed by SPSS software version ۲۶.۰.Results: In this study, we used a logistic regression test to indicate that smoking had a significant relationship with subsequent plasmapheresis (P=۰.۰۰۱). We also found a significant relationship between cigarette smoking and plasmapheresis (P<۰.۰۰۱). Furthermore, old age and diabetes were related to
ICU admission (P=۰.۰۰۱ and P<۰.۰۰۰, respectively), and male gender and hypertension were related to plasmapheresis (P=۰.۰۰۷ and P=۰.۰۰۱, respectively). Moreover, only old age was related to mortality caused by
COVID-۱۹ infection (P=۰.۰۲۵).Conclusion: Considering the issue of the smoking paradox in COVID-۱۹, the association between smoking and
COVID-۱۹ disease was evaluated in this study. it was found that smoking is related to the need for plasmapheresis and was not related to
ICU admission or death. Cigarette smoking had the same association. It should be noted that plasmapheresis had no significant relation with
ICU admission and death. Moreover, hookah smoking had no relationship with plasmapheresis,
ICU admission, and death. This study also evaluated other factors such as age, gender, and medical conditions such as hypertension, diabetes, and cardiovascular disease and their effect on COVID-۱۹. We found that only old age was related to mortality caused by COVID-۱۹.