Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2020 Sep 8:2020:7590207.
doi: 10.1155/2020/7590207. eCollection 2020.

The Effect of Smoking on COVID-19 Symptom Severity: Systematic Review and Meta-Analysis

Askin Gülsen  1 , Burcu Arpinar Yigitbas  2 , Berat Uslu  2 , Daniel Drömann  1 , Oguz Kilinc  3
Affiliations
Meta-Analysis

The Effect of Smoking on COVID-19 Symptom Severity: Systematic Review and Meta-Analysis

Askin Gülsen et al. Pulm Med. .

Abstract

Background: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SAR2-COV-2) and was first identified in Wuhan, China, in December of 2019, but quickly spread to the rest of the world, causing a pandemic. While some studies have found no link between smoking status and severe COVID-19, others demonstrated a significant one. The present study aimed to determine the relationship between smoking and clinical COVID-19 severity via a systematic meta-analysis approach.

Methods: We searched the Google Scholar, PubMed, Scopus, Web of Science, and Embase databases to identify clinical studies suitable for inclusion in this meta-analysis. Studies reporting smoking status and comparing nonsevere and severe patients were included. Nonsevere cases were described as mild, common type, nonintensive care unit (ICU) treatment, survivors, and severe cases as critical, need for ICU, refractory, and nonsurvivors.

Results: A total of 16 articles detailing 11322 COVID-19 patients were included. Our meta-analysis revealed a relationship between a history of smoking and severe COVID-19 cases (OR = 2.17; 95% CI: 1.37-3.46; P < .001). Additionally, we found an association between the current smoking status and severe COVID-19 (OR = 1.51; 95% CI: 1.12-2.05; P < .008). In 10.7% (978/9067) of nonsmokers, COVID-19 was severe, while in active smokers, severe COVID-19 occurred in 21.2% (65/305) of cases.

Conclusion: Active smoking and a history of smoking are clearly associated with severe COVID-19. The SARS-COV-2 epidemic should serve as an impetus for patients and those at risk to maintain good health practices and discontinue smoking. The trial is registered with the International Prospective Register of Systematic Reviews (PROSPERO) CRD42020180173.

PubMed Disclaimer

Conflict of interest statement

The authors have stated explicitly that there are no conflicts of interest in connection with this article.

Figures

Figure 1
Figure 1
PRISMA flow diagram of study selection procedures.
Figure 2
Figure 2
(a) Prevalence of smoking in severe COVID-19 patients. (b) Funnel plot for meta-analysis of the prevalence of smoking in severe COVID-19 patients. (c) Prevalence of smoking among severe COVID-19 patients after the exclusion of studies by Qi et al. [16] and Zhang et al. [23]. (d) Funnel plot for the meta-analysis of smoking among severe COVID-19 patients after the exclusion of studies by Qi D et al. [16] and Zhang R et al. [23].
Figure 3
Figure 3
(a) Comparison of smoking status in severe COVID-19 patients. (b) Funnel plot for the meta-analysis of smoking among severe COVID-19 patients. (c) Comparison of smoking status among severe COVID-19 patients after the exclusion of a study by Zhang et al. [23]. (d) Funnel plot for the meta-analysis of smoking among severe COVID-19 patients after the exclusion of a study by Zhang et al. [23].
See this image and copyright information in PMC

References

    1. World Health Organisation. Coronavirus disease (COVID-2019) situation reports. https://www.who.int/docs/default-source/coronaviruse/situation-reports/2....
    1. Coronavirus Worldometer. Country-specific case fatality rates (CFR) of COVID-19 patients. August 2020 https://www.worldometers.info/coronavirus/
    1. Yang J., Zheng Y., Gou X., et al. Prevalence of comorbidities and its effects in patients infected with SARS-CoV-2: a systematic review and meta-analysis. International Journal of Infectious Diseases. 2020;94:91–95. doi: 10.1016/j.ijid.2020.03.017. - DOI - PMC - PubMed
    1. CDC COVID-19 Response Team, CDC COVID-19 Response Team, Chow N., et al. Preliminary Estimates of the Prevalence of Selected Underlying Health Conditions Among Patients with Coronavirus Disease 2019- United States, February 12-March 28, 2020. MMWR. Morbidity and Mortality Weekly Report. 2020;69(13):382–386. doi: 10.15585/mmwr.mm6913e2. - DOI - PMC - PubMed
    1. Garg S., Kim L., Whitaker M., et al. Hospitalization Rates and Characteristics of Patients Hospitalized with Laboratory-Confirmed Coronavirus Disease 2019 — COVID-NET, 14 States, March 1–30, 2020. MMWR. Morbidity and Mortality Weekly Report. 2020;69(15):458–464. doi: 10.15585/mmwr.mm6915e3. - DOI - PMC - PubMed

LinkOut - more resources