In the overall analysis of 6 non-East Asian studies [17–19, 25, 28, 29], including a total of 1391 patients undergoing clopidogrel-based antiplatelet therapy, those carrying CYP2C19 LOF alleles were found at higher risk of stroke recurrence compared to non-carriers (RR: 1.68, 95%CI: 1.04–2.71, P = 0.03, Fig. 2A), and significant between-study heterogeneity was not observed (I2 = 17%, P = 0.31). This evidence concerns the gene CYP2C19 and Stroke.