Figure 3. Association of tobacco smoking history with severe COVID-19.
(a) Distribution of nonsmokers and smokers in non-severe, ICU recovery and death.
(b) Statistical significance of smoking risk where two-tailed Fisher’s exact tests were used for this study.
(c) Forest plot showing 2.5-fold risk by fixed effect model (random effect model: OR=2.81, 95% CI 1.78-4.45, Z=4.41, P<0.0001).
(d) Funnel plot showing no publication bias.