Effects of Smoking on Major Adverse Cardiovascular Events in Patients With Coronary Artery Spasm: A Systematic Review and Meta-Analysis

Background: Smoking is an established independent risk factor for coronary artery spasm (CAS), but its effects on major adverse cardiovascular events (MACE) in patients with CAS have not been systematically assessed.

Methods: This systematic review and meta-analysis of studies published from January 2000 to July 2023 was conducted to examine the relationship between smoking and MACE in patients with CAS. Data on MACE were obtained from both smoking and non-smoking CAS patient groups. The effects of smoking on MACE in patients with CAS were assessed through meta-analysis, utilising Stata 17.0 software for all statistical analyses.

Results: Nine studies, encompassing 9,376 patients, from Japan (5 studies), Korea (4 studies) and Spain (1 study) were included in the final analysis. Meta-analysis revealed that smoking significantly impacted MACE in patients with CAS (RR 1.965; 95% CI 1.348-2.865), a finding further validated by sensitivity analyses. Subgroup analyses identified a stronger correlation between smoking and increased MACE endpoints in Japanese patients and in those with >3 years of follow-up.

Conclusions: This meta-analysis strongly indicates that smoking escalates the risk of MACE in patients with CAS, with a more pronounced association observed in Japanese patients and those with extended follow-up periods.