Table 2.

Pleiotropy and heterogeneity analyses

Exposure	Outcome	No. of SNPs	MR‐Egger regression		MR PRESSO		Heterogeneity analyses
			Intercept	p_intercept	Global test p	Correct p *	Method	Q	Q_pval
Critically ill COVID‐19	LTL	6	0.001	0.885	0.004	0.174	IVW	29.853	<0.001
							MR‐Egger	29.677	<0.001
The reverse MR analyses
LTL	Critically ill COVID‐19	97	−0.006	0.352	0.485	NA	IVW	90.434	0.497
							MR‐Egger	89.465	0.496

Abbreviations: IVW, inverse variance weighted; LTL, leukocyte telomere length; MR PRESSO, Mendelian randomization pleiotropy residual sum and outlier; SNPs, single‐nucleotide polymorphisms.

^*If MR PRESSO global test detects the horizontal pleiotropy and there is a significant difference before and after removing the outlier, correct p is calculated by removing instruments variants that have horizontal pleiotropy.