[The impact of lung diseases, smoking and e-cigarette use on the severity of COVID-19 illness at diagnosis].

Axelsson, Gisli Thor; Eythorsson, Elias Saebjorn; Hardardottir, Hronn; Gudmundsson, Gunnar; Hansdottir, Sif

INTRODUCTION The COVID-19 pandemic has caused public health and economic turmoil across the globe. Severe COVID-19 disease most often presents with pneumonia and complications in acutely ill patients often stem from the lungs. The associations of lung disease, smoking and e-cigarette use with the incidence and severity of COVID-19 are unclear on a population level. METHODS Data on 1761 patients from the Icelandic outpatient Landspitali COVID-19 Clinic were used. The prevalence of smoking, e-cigarette use and underlying lung diseases was calculated in the cohort, with stratification based on age groups and a clinical classification of symptom severity. It was tested whether these prevalences differed between age groups and classes of symptom severity. RESULTS Most patients were in the age group between 35-54 years of age and a large majority had mild symptoms at diagnosis. The prevalence of smoking was 6% with the highest prevalence among 35-54 year olds. The prevalence of e-cigarette use was 4%. It was most prevalent in the age group between 18-34 years. There was no difference in the prevalence of smoking or e-cigarette use between classes of symptom severity. The prevalence of lung disease was 9%. It was higher among older patients and patients with more severe symptoms. CONCLUSION The age distribution and prevalence of lung disease and their risk factors are described in the context of COVID-19 incidence and symptom severity in a whole-nation cohort of Icelanders. The cohort is younger and had less severe symptoms than in many previosly published studies of COVID-19. Interestingly, the prevalences of smoking and e-cigarette use were lower than in the Icelandic general population and they were not associated with symptom severity at diagnosis. To conclude, the results presented here indicate that underlying lung diseases are prevalent among people with severe COVID-19 symptoms but fail to demonstrate an association between cigarette smoking or e-cigarette smoking with COVID-19 severity.