Systematic review with meta-analysis of the epidemiological evidence in Europe, Israel, America and Australasia on smoking and COVID-19

Table 7 Results for endpoint: Worsened or died¹

Selection of estimates2	Statistic3	Ever vs never	Current vs non-current	Current vs never	Former vs never	Closest to current	Closest to ever
Unadjusted4	EE (95%CI)	1.34 (1.00-1.79)	1.31 (1.06-1.62)	1.21 (0.35-4.17)	2.01 (0.67-6.09)	1.27 (1.15-1.39)	1.36 (1.15-1.62)
	n	5	5	3	3	9	9

¹Seven studies considered death among those admitted to the intensive care unit (ICU), and one of these and one other considered death among those mechanically ventilated. One considered admission to ICU or death among those hospitalized with severe coronavirus disease 2019.

²All estimates were unadjusted.

³EE = effect estimate from random-effects meta-analysis.

⁴The data are from nine studies, five reporting odds ratio (OR)s, two relative risk (RR)s and two RRs and hazard ratios, one of these also reporting ORs. CI: Confidence interval.