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Meta-Analysis
. 2020 Aug;15(5):845-852.
doi: 10.1007/s11739-020-02355-7. Epub 2020 May 9.

Systematic review of the prevalence of current smoking among hospitalized COVID-19 patients in China: could nicotine be a therapeutic option?

Konstantinos Farsalinos  1 , Anastasia Barbouni  2 , Raymond Niaura  3
Affiliations
Meta-Analysis

Systematic review of the prevalence of current smoking among hospitalized COVID-19 patients in China: could nicotine be a therapeutic option?

Konstantinos Farsalinos et al. Intern Emerg Med. 2020 Aug.

Abstract

The effects of smoking on Corona Virus Disease 2019 (COVID-19) are currently unknown. The purpose of this study was to systematically examine the prevalence of current smoking among hospitalized patients with COVID-19 in China, considering the high-population smoking prevalence in China (26.6%). A systematic review of the literature (PubMed) was performed on April 1. Thirteen studies examining the clinical characteristics of hospitalized COVID-19 patients in China and presenting data on the smoking status were found. The pooled prevalence of current smoking from all studies was calculated by random-effect meta-analysis. To address the possibility that some smokers had quit shortly before hospitalization and were classified as former smokers on admission to the hospital, we performed a secondary analysis in which all former smokers were classified as current smokers. A total of 5960 patients were included in the studies identified. The current smoking prevalence ranged from 1.4% (95% CI 0.0-3.4%) to 12.6% (95% CI 10.6-14.6%). An unusually low prevalence of current smoking was observed from the pooled analysis (6.5%, 95% CI 4.9-8.2%) as compared to population smoking prevalence in China. The secondary analysis, classifying former smokers as current smokers, found a pooled estimate of 7.3% (95% CI 5.7-8.9%). In conclusion, an unexpectedly low prevalence of current smoking was observed among patients with COVID-19 in China, which was approximately 1/4th the population smoking prevalence. Although the generalized advice to quit smoking as a measure to reduce health risk remains valid, the findings, together with the well-established immunomodulatory effects of nicotine, suggest that pharmaceutical nicotine should be considered as a potential treatment option in COVID-19.

Keywords: ACE2; COVID-19; Hospitalization; Inflammation; Nicotine; SARS-CoV-2; Smoking.

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Conflict of interest statement

The authors report no competing interests for the past 36 months. For the past 60 months, two of his studies were funded by the non-profit association AEMSA and one study was funded by the non-profit association Tennessee Smoke-Free Association. AB reports no conflict of interest. AB has nothing to report. RN receives funding from the Food and Drug Administration Center for Tobacco Products via contractual mechanisms with Westat and the National Institutes of Health. Within the past three years, he has served as a paid consultant to the Government of Canada and the FDA via contracts with Industrial Economics Inc., and has received an honorarium for a virtual meeting from Pfizer Inc.

Figures

Fig. 1
Fig. 1
Random effects pooled prevalence of current smoking observed from 13 studies of hospitalized COVID-19 patients in China. The forest plot depicts the fractional prevalence of smokers in each study. The size of the dark squares is proportional to the weight each study has in determining the combined effect size estimate. P < 0.001 for heterogeneity
See this image and copyright information in PMC

Comment in

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