Reply.

Dear Editor:

The prevalence of smoking in the Spanish population is higher than in our study, as indicated by Rossato and Di Vicenzo. Indeed, the prevalence of smoking in the Spanish population is 25% of active smokers. However, the prevalence of smoking varies according to age group, being considerably lower in those over 65 years. Our study population included only hospitalized patients. Advanced age is a predisposing factor for severe COVID-19 infection and hospitalization. The patients in our study had a mean age of 68.6 years, in whom the overall prevalence of smoking was already lower (9.96%) than in Spain.

Other studies have reported lower smoking rates than their respective populations. The low prevalence reported among COVID patients may be due to an underestimation of smoking. Data collection conditions in overwhelmed health systems are particularly difficult. As indicated in the discussion section, this is a retrospective study and is limited in the respect that a complete smoking history (time of smoking cessation, degree of exposure, …) was not available.

We should pay attention to the scientific messages about smoking and COVID-19. Nowadays, there is no solid evidence that smoking has a protective effect against COVID-19. Our study is based on 14,260 patients and the conclusions are supported by the results. The low prevalence of current smoking in our study cannot be considered a “protective” factor. We did not analyze the risk of infection or hospitalization based on smoking or non-smoking. We studied the severity of patients once admitted based on smoking history. A study of patients with COVID-19 infection could be considered to analyze the risk of admission according to smoking history. In any case, our analysis shows that among smokers the risk of disease progression is significantly higher.