Effect of cytochrome P450 2C19*17 allelic variant on cardiovascular and cerebrovascular outcomes in clopidogrel-treated patients: A systematic review and meta-analysis.

Background: We aimed to evaluate the associations of gain-of-function allele of *17 and risk of clinical events in clopidogrel-treated patients with cardiovascular and cerebrovascular diseases (CCVDs).

Materials And Methods: Literature search was conducted in PubMed, EMBASE, and Cochrane Library. Odds ratio (OR) combined with 95% confidence interval (CI) was the pooled statistics. Subgroup analysis was performed by disease type, bleeding events, and race.

Results: Thirteen eligible studies involving 14,239 patients with *17 carriers or noncarriers were included in the meta-analysis. *17 was significantly related to decreased risk of major adverse cardiovascular and cerebrovascular events (MACCEs) in patients with coronary artery disease (CAD) (OR = 0.76, 95% CI: 0.60-0.98, = 0.03), however, irrelevant with stent thrombosis in neither CAD nor ischemic heart disease patients. *17 was also significantly linked to decreased risk of high platelet reactivity (HPR) in CCVD patients (OR = 0.61, 95% CI: 0.43-0.88, = 0.008). Meanwhile, *17 was significantly associated with bleeding risk in CCVD patients (OR = 1.89, 95% CI: 1.09-3.25, = 0.02) but not related to major bleeding risk (OR = 1.35, 95% CI: 0.87-2.08, = 0.18). Several outcomes in Caucasian subgroup were reverse to the overall results, such as bleeding events and HPR, which lacked significance.

Conclusion: *17 had a significant effect on the reduced risks of MACCE and HPR as well as increased bleeding risk, but not on the risks of stent thrombosis and major bleeding in clopidogrel-treated CCVD patients. Outcomes might be different in different races.