Distribution of CYP2C19 genetic polymorphisms and pharmacogenomic implications in 11,710 patients with cardiovascular and cerebrovascular conditions: a large population-based study in eastern China

Objective To investigate the distribution of CYP2C19 genetic polymorphisms among patients with cardiovascular and cerebrovascular conditions in Taizhou, Zhejiang Province, and to evaluate their pharmacogenomic implications for genotype-guided antiplatelet therapy. Methods We conducted a retrospective population-based analysis of 11,710 patients with cardiovascular and cerebrovascular conditions who underwent CYP2C19 genotyping at Taizhou Hospital of Zhejiang Province between January 2023 and December 2025. Genotyping of CYP2C19 *2 and CYP2C19 *3 alleles was performed using fluorescence-based quantitative polymerase chain reaction (PCR). Genotype and allele frequencies were calculated using the gene counting method. Hardy–Weinberg equilibrium (HWE) was assessed using the χ 2 test. Differences in genotype and phenotype distributions across gender and age groups were analyzed using the χ 2 test, and P < 0.05 was considered statistically significant. Results The allele frequencies of CYP2C19 *1, *2, and *3 were 61.01%, 34.11%, and 4.88%, respectively. The distribution of metabolic phenotypes was as follows: normal metabolizers (NMs), 37.15%; intermediate metabolizers (IMs), 47.73%; and poor metabolizers (PMs), 15.12%. Genotype distributions were consistent with Hardy–Weinberg equilibrium (P > 0.05). No significant differences were observed in genotype or phenotype distributions across gender or age groups (P > 0.05). Regional comparisons showed that the distribution pattern in Taizhou was consistent with that reported in other regions of eastern China but differed from southern and western populations (P < 0.05). The proportion of individuals carrying at least one loss-of-function allele (IMs + PMs) reached 62.85%, indicating a high prevalence of genotypes associated with reduced clopidogrel responsiveness. Conclusion This large population-based pharmacogenomic study demonstrates a high prevalence of CYP2C19 loss-of-function alleles in patients with cardiovascular and cerebrovascular conditions from Taizhou. These findings support the clinical value of CYP2C19 genotyping for individualized antiplatelet therapy and provide important genetic epidemiology data for precision medicine in this population.