Smoking doubles the risk of death from COVID-19: a meta-analysis of recent research

COVID-19 poses a serious health problem, as it has high mortality rates, while the provoking factors are not fully understood. Some studies show that risk factors are the presence of arterial hypertension, chronic obstructive pulmonary disease (COPD), hypercholesterolemia, diabetes mellitus (DM) and cardiovascular diseases in a patient, and mortality is also higher among older men.

At the same time, it is also im

portant to study the influence of modifiable factors and protomax on the severity of COVID-19 infection for the early detection of persons with an increased risk of mortality. For example, smoking is a risk factor for the development of acute respiratory distress syndrome (ARDS) and is associated with higher costs of intensive care. In theory, smoking can directly affect the outcome of COVID-19 patients, increasing inflammation and disrupting endothelial function of the cardiopulmonary system.

However, studies related to the effect of smoking on the severity of COVID-19 infection have shown conflicting results since the start of the pandemic. This meta-analysis included 10 studies with 11,189 patients. Of these, 1,867 patients (16.7%) were smokers or ex-smokers, and the mortality rate among them was 29.4% compared to 17.0% among nonsmokers.

Only four studies involving 532 patients were included in the meta-analysis comparing mortality rates between current and former smokers. The mortality rate among current smokers was 32.1%, while the mortality rate among former smokers was 21.5%.

It is known that smokers are predisposed to more severe infections and the likelihood of developing ARDS in smokers is greater than in non-smokers, as is the likelihood of a more severe course of respiratory pathology due to reduced lung reserve and altered physiology. In addition, smoking can alter the innate adaptive function of the immune system, which leads to exacerbation of pathological immune responses and weakening of the normal physiological functions of the immune system. And, in addition, smoking causes damage to the lung endothelium and, accordingly, a violation of the barrier function, which can increase alveolar permeability and the risk of pulmonary edema.

In addition to the direct pathological cascade associated with smoking, the presence of pre-existing comorbidities can also contribute to severe illness. Smoking is an independent risk factor for COPD, diabetes mellitus, and cardiovascular disease. According to numerous studies, the presence of these comorbidities led to more severe COVID-19 and poor outcomes.

Thus, a meta-analysis showed that smoking can double the risk of death in patients with COVID-19. Compared to former smokers, smokers had an approximately 50% greater risk of mortality from COVID-19, although the differences were not statistically significant.