Current smoking, former smoking, and adverse outcome among hospitalized COVID-19 patients: a systematic review and meta-analysis.
Ther Adv Chronic Dis
; 11: 2040622320935765, 2020.
Article
in English
| MEDLINE | ID: covidwho-619218
ABSTRACT
BACKGROUND:
The purpose of this study was to examine the prevalence and effects of current smoking on adverse outcomes among hospitalized COVID-19 patients.METHODS:
A systematic review of the literature (PubMed) identified 18 (from a total of 1398) relevant studies. Pooled current smoking prevalence was compared with the gender-adjusted and gender and age-adjusted, population-based expected prevalence by calculating prevalence odds ratio (POR). The association between current, compared with non-current and former, smoking and adverse outcome was examined. A secondary analysis was performed by including 12 pre-publications (30 studies in total). All analyses were performed using random-effects meta-analysis.RESULTS:
Among 6515 patients, the pooled prevalence of current smoking was 6.8% [95% confidence interval (CI) 4.8-9.1%]. The gender-adjusted POR was 0.20 (95% CI 0.16-0.25, p < 0.001), and the gender and age-adjusted POR was 0.24 (95% CI 0.19-0.30, p < 0.001). Current smokers were more likely to have an adverse outcome compared with non-current smokers [odds ratio (OR) 1.53, 95%CI 1.06-2.20, p = 0.022] but less likely compared with former smokers (OR 0.42, 95% CI 0.27-0.74, p = 0.003). When pre-publications were added (n = 10,631), the gender-adjusted POR was 0.27 (95% CI 0.19-0.38, p < 0.001) and the gender and age-adjusted POR was 0.34 (95% CI 0.24-0.48, p < 0.001).CONCLUSION:
This meta-analysis of retrospective observational case series found an unexpectedly low prevalence of current smoking among hospitalized patients with COVID-19. Hospitalized current smokers had higher odds compared with non-current smokers but lower odds compared with former smokers for an adverse outcome. Smoking cannot be considered a protective measure for COVID-19. However, the hypothesis that nicotine may have a protective effect in COVID-19 that is partially masked by smoking-related toxicity and by the abrupt cessation of nicotine intake when smokers are hospitalized should be explored in laboratory studies and clinical trials using pharmaceutical nicotine products.
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Type of study:
Observational study
/
Prognostic study
/
Randomized controlled trials
/
Reviews
/
Systematic review/Meta Analysis
Language:
English
Journal:
Ther Adv Chronic Dis
Year:
2020
Document Type:
Article
Affiliation country:
2040622320935765
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