Association of smoking status with outcomes in hospitalised patients with COVID-19

Abstract

IntroductionSmoking causes inflammation of the lung epithelium by releasing cytokines and impairing mucociliary clearance. Some studies have linked smoking with severity of illness of COVID-19 whereas others have found no such association.MethodsThis was a retrospective analysis of all adults hospitalised with COVID-19 from 9 March to 18 May 2020.Results1173 patients met the study criteria. 837 patients never smoked whereas 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 chronic obstructive pulmonary disease (19% vs 6%, p<0.001), HIV 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=0.3), chronic kidney disease (11% vs 8%, p=0.037) and end-stage renal disease (10% vs 6%, p=0.009) compared with non-smokers. Outcome analysis showed that 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 among smokers only current smokers had higher risk of death compared with never smokers (HR 1.61, 95% CI 1.22 to 2.12, p<0.001). In the multivariate approach, Cox model for the survival, female sex, young age, low serum lactate dehydrogenase and systemic steroid use were associated with overall improved survival.ConclusionIn our large single-centre retrospective database of patients hospitalised with COVID-19, smoking was associated with development of critical illness and higher likelihood of death.

Comparing Decision Tree-Based Ensemble Machine Learning Models for COVID-19 Death Probability Profiling

“…The resulting profile confirms and reinforces previous studies’ results [1-5, 18, 26, 27] on COVID-19 risk factors. The profile is also consistent with the exponential increase in death risk with age, that we analyzed inferentially.…”

“…For the boosting algorithms, the AdaBoost used 100 trees of maximum depth equal to 2, and SAMME.R algorithm, the maximum number of features when looking for the best split was set to the square root of the number of features 5 . In the case of the boosted RFs and boosted ERTs we also used 100 base estimators, each comprised of 100 trees.…”

“…Different studies have identified age group, sex and underlying comorbidity or disease as critical factors for disease severity and mortality risk [1][2][3][4][5]. In the current work, we use these three factors as feature variables in machine learning models for extracting a profile for COVID-19 death probability, conditional on these three risk factors, using the US Centers for Disease Control and Prevention (CDC)'s COVID-19 case surveillance data sample 1 which contains a large sample of COVID-19 confirmed cases with records for these three factors.…”

Telemedicine for Tobacco Cessation and Prevention to Combat COVID-19 Morbidity and Mortality in Rural Areas

“…Concerning COVID-19 mortality-related risk factors, of 11 admitted patients who were current smokers in China, five did not survive ( 28 ). A more recent U.S. study found that current smokers, when compared to never smokers, were at increased risk of needing mechanical ventilation, having severe-to-critical illness, lower survival time in days, and more deaths ( 34 ). Concerning non-combustible tobacco products, a study found that 13–24-year-olds who engaged in exclusive e-cigarette use and dual-use of e-cigarettes and combustible cigarettes were at significantly increased odds to have positive COVID-19 diagnoses, while accounting for clustering by U.S. states and regions ( 35 ).…”

SARS CoV-2 adenovirus and RNA based vaccines potential autoimmune complications: could we lower the chances?

“…The first group are smokers; cigarette smoke has been reported to lead to an enhanced risk of inflammatory and autoimmune diseases [14]. Smokers are more likely to develop critical COVID-19 requiring mechanical ventilation [15] that might lead to a higher mortality rate [16,17]. Interestingly, alarms about the danger of misreading non-significant or inconclusive frequentist results containing several possible biases of a contradictory hypotheses have been raised [18,19].…”