Polygenic Risk Score for the Efficacy of Clopidogrel in Patients With Minor Stroke or Transient Ischemic Attack: A Post Hoc Analysis of the CHANCE Trial

BACKGROUND: Dual antiplatelet therapy (DAPT) with clopidogrel and aspirin is recommended for secondary prevention in patients with a minor stroke or transient ischemic attack. However, the effectiveness of DAPT can be significantly influenced by genetic variations. This study aimed to estimate the impact of multiple single-nucleotide polymorphisms across various genes on DAPT efficacy using polygenic risk score (PRS). METHODS: In this post hoc analysis, we included 2905 patients from the CHANCE trial (Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events), which enrolled a total of 5170 patients in China between October 2009 and July 2012. The primary outcome was new stroke within 90 days. Sixteen single-nucleotide polymorphisms across 7 genes involved in clopidogrel metabolism were selected for PRS development. PRS were calculated by summing single-nucleotide polymorphisms from each individual. The Cox proportional-hazards regression model was utilized to estimate the hazard ratio (HR) and 95% CIs of PRS. The predictive value of PRS was estimated by C statistic and compared with a previously validated model. In patients receiving DAPT, higher PRSs were associated with increased risk of new stroke and composite vascular events at 90 days (adjusted HR per SD increase was 1.51 [95% CI, 1.15-1.99]) and at 1 year (adjusted HR per SD increase was 1.34 [95% CI, 1.08-1.67]). The C statistic for predicting 90-day new stroke using the PRS developed in this study was 0.57 (95% CI, 0.52-0.62), compared with 0.52 (95% CI, 0.48-0.55) for the ABCD-GENE score. CONCLUSIONS: Using PRS integrating multiple genes may enhance the precision of secondary prevention strategies for patients with minor stroke or transient ischemic attack in the short and long term. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00979589.