Smoking status related to Covid-19 mortality and disease severity in a veteran population

Introduction: Cigarette smoking is associated with development of significant comorbidities. Patients with underlying comorbidities have been found to have worse outcomes associated with Coronavirus Disease 2019 (Covid-19). This study evaluated 30-day mortality in Covid-19 positive patients based on smoking status. Methods: This retrospective study of veterans nationwide examined Covid-19 positive inpatients between March 2020 and January 2021. Bivariate analysis compared patients based on smoking history. Propensity score matching adjusted for age, gender, race, ethnicity, Charlson comorbidity index (0–5 and 6–19) and dexamethasone use was performed. A multivariable logistic regression with backwards elimination and Cox Proportional Hazards Ratio was utilized to determine odds of 30-day mortality. Results: The study cohort consisted of 25,958 unique Covid-19 positive inpatients. There was a total of 2,995 current smokers, 12,169 former smokers, and 8,392 non-smokers. Death was experienced by 13.5% (n = 3503) of the cohort within 30 days. Former smokers (OR 1.15; 95% CI, 1.05–1.27) (HR 1.13; 95% CI, 1.03–1.23) had higher risk of 30-day mortality compared with non-smokers. Former smokers had a higher risk of death compared to current smokers (HR 1.16 95% CI 1.02–1.33). The odds of death for current vs. non-smokers did not significantly differ. Conclusion: Compared to veteran non-smokers with Covid-19, former, but not current smokers with Covid-19 had a significantly higher risk of 30-day mortality.