Association of Smoking Status with Outcomes in Hospitalized COVID-19 Patients
Abstract Introduction: Smoking causes inflammation of the lung epithelium by releasing cytokines and impairing muco-ciliary clearance. Some studies have linked smoking with severity of illness of COVID-19 whereas others have found no such association.Methods: This was a retrospective analysis of all adults hospitalized with COVID-19 from March 09 to May 18, 2020. Results: 1173 patients met the study criteria. 837 patients never smoked and 336 patients were either current smokers or past smoker and were grouped together in smokers group. Patients in smokers group were more likely to be male and had higher incidence of underlying COPD (19% vs. 6%, p<0.001), human immunodeficiency virus infection (11% vs. 5%,p<0.001), cancer (11% vs. 6%, p=0.005), congestive heart failure (15% vs. 8%, p<0.001), coronary artery disease (15% vs. 9%, p=0.027), chronic kidney disease (11% vs. 8%, p=0.037), and end-stage renal disease (10% vs. 6%, p=0.009) compared to non-smokers. Smokers were more likely to develop critical illness requiring mechanical ventilation (47% vs. 37% p=0.005). Univariate Cox model for survival analysis by smoking status showed that smokers only current smokers had higher risk of death compared to never-smokers (HR 1.61, 95% confidence interval 1.22–2.12, p<0.001). In the multivariate approach Cox model for the survival, female sex, age, LDH and systemic steroid use were associated with overall survival.Conclusion: In our large single center retrospective database of patients hospitalized with COVID-19, smoking was associated with development of critical illness and higher likelihood of death