International Journal of Preventive Medicine (Int J Prev Med)2008-780213122023020127452745ENTobacco Prevention and Control Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran20230201<p><strong>Background</strong>: Few studies have shown that smokers are more likely than non‑smokers to have coronavirus disease 2019 (COVID‑19), whereas some reports indicate that smokers are under‑represented among those requiring hospital treatment for this illness. This study was designed and implemented for investigating the severity and outcome of COVID‑19 based on smoking.</p><p><strong>Materials and Methods:</strong> This was a cross‑sectional study implemented in Tehran and Ahvaz with all COVID‑19 hospitalization patients from February to June 2021. Four categories selected for severity and worst outcomes. They are admission in the intensive care unit (ICU), lung involvement more than 50%, using more than three medications, and death. A check list of demographic data and smoking history was completed and analyzed.</p><p><strong>Results</strong>: A total of 11,112 patients were male (61.1%), and the mean age was 47.9 ± 11.3. A total of 1508 smokers (8.3%) were seen with any type of tobacco consumption. The frequency of ICU admission in the smokers is significantly higher than that in non‑smokers (23.9% vs. 18.8%). A total of 668 (44.3%) smokers had more than 50% ground glass opacity in lungs, whereas 5340 non‑smokers (32.1%) had so. Use of more than three medications in the smokers was significantly higher (70.6% vs. 52%). A comparison between patients based on smoking indicates that the death rate was significantly higher in smokers (31.6% vs. 25.6%).</p><p><strong>Conclusions</strong>: Although smoking rates in COVID‑19 patients are lower than those in the general population, the consequences and mortality are higher in smokers.</p>http://ijpm.mui.ac.ir/index.php/ijpm/article/view/2745http://ijpm.mui.ac.ir/index.php/ijpm/article/download/2745/717718589