Assessing Smoking Status and Risk of SARS-CoV-2 Infection: A Machine Learning Approach among Veterans

• Published in: Healthcare (Basel) 2022-07, Vol.10 (7), p.1244
• Main Authors: Nono Djotsa, Alice B S, Helmer, Drew A, Park, Catherine, Lynch, Kristine E, Sharafkhaneh, Amir, Naik, Aanand D, Razjouyan, Javad, Amos, Christopher I
• Format: Article
• Language: English
• Subjects: Age; Body mass index; Cancer; Coronaviruses; COVID-19; Datasets; Diabetes; Feature selection; Hispanic Americans; Hypertension; Infections; Machine learning; Pandemics; Pre-existing conditions; R&D; Research & development; Respiratory diseases; SARS Coronavirus 2; Severe acute respiratory syndrome coronavirus 2; smoking; Variables; veteran
• ISSN: 2227-9032; 2227-9032
• DOI: 10.3390/healthcare10071244

The role of smoking in the risk of SARS-CoV-2 infection is unclear. We used a retrospective cohort design to study data from veterans' Electronic Medical Record to assess the impact of smoking on the risk of SARS-CoV-2 infection. Veterans tested for the SARS-CoV-2 virus from 02/01/2020 to 02/28/2021 were classified as: Never Smokers (NS), Former Smokers (FS), and Current Smokers (CS). We report the adjusted odds ratios (aOR) for potential confounders obtained from a cascade machine learning algorithm. We found a 19.6% positivity rate among 1,176,306 veterans tested for SARS-CoV-2 infection. The positivity proportion among NS (22.0%) was higher compared with FS (19.2%) and CS (11.5%). The adjusted odds of testing positive for CS (aOR:0.51; 95%CI: 0.50, 0.52) and FS (aOR:0.89; 95%CI:0.88, 0.90) were significantly lower compared with NS. Four pre-existing conditions, including dementia, lower respiratory infections, pneumonia, and septic shock, were associated with a higher risk of testing positive, whereas the use of the decongestant drug phenylephrine or having a history of cancer were associated with a lower risk. CS and FS compared with NS had lower risks of testing positive for SARS-CoV-2. These findings highlight our evolving understanding of the role of smoking status on the risk of SARS-CoV-2 infection.