A bidirectional Mendelian randomization analysis between COVID-19 and cardiac arrest

Epidemiological studies link COVID-19 to increased cardiac arrest (CA) risk, but causality remains unclear due to potential confounding factors in observational studies . We conducted a Mendelian randomization (MR) analysis using genome-wide association study (GWAS) data, employing COVID-19-associated single nucleotide polymorphisms (SNPs) with significance values smaller than 5 × 10⁻⁸. We calculated inverse-variance weighted (IVW) MR estimates and performed sensitivity analyses using MR methods robust to horizontal pleiotropy. Additionally, a reverse MR analysis was conducted using CA-associated SNPs with significance values smaller than 1 × 10⁻⁵. Results indicated that infected COVID-19 (OR = 1.12, 95% CI = 0.47-2.67,