What is the clinical evidence from this study?

Study design: Meta-Analysis. Population: Ischemic stroke or TIA (n=11786). Intervention: Risk factors for clopidogrel resistance vs. Non-resistant patients. Primary outcome: clopidogrel resistance (OR 1.55, 95% CI 1.22-1.97).

What question did this study set out to answer?

This research aims to quantify the predictors of clopidogrel resistance in patients with ischemic stroke or TIA.

May 8, 2026

Abstract Number: Esoc2026a2001 Risk Factors for Clopidogrel Resistance in Patients With Ischemic Stroke or Tia: A Systematic Review and Meta-Analysis of Sixty-Five Primary Studies

Key Result

Diabetes mellitus increased the odds of clopidogrel resistance (OR 1.55; 95% CI 1.22–1.97), whereas male sex, current smoking, and the CYP2C19 2 GG genotype (OR 0.45; 95% CI 0.26–0.78) lowered odds.

Key Points

This research aims to quantify the predictors of clopidogrel resistance in patients with ischemic stroke or TIA.
Systematic review conducted following PRISMA guidelines, searching four databases.
Included 65 studies with 11,786 patients, focusing on clopidogrel resistance.
Statistical analysis of demographic, clinical, and genetic data for 34 studies (6,053 patients).
Clopidogrel-resistant patients were slightly older (MD 1.92 years; 95% CI 1.15–2.68) with higher HbA1c (MD 0.27%; 95% CI 0.07–0.46).
Diabetes mellitus was associated with increased odds of resistance (OR 1.55; 95% CI 1.22–1.97).
Male sex (OR 0.75; 95% CI 0.65–0.86) and the CYP2C19 2 GG genotype (OR 0.45; 95% CI 0.26–0.78) correlated with lower odds of resistance.

Study Design

Type

Meta-Analysis (n=11,786)

Structured PICO

What are the sociodemographic, clinical, and genetic predictors of clopidogrel resistance in patients with ischemic stroke or TIA?

Population

65 studies (11,786 patients) of adults (≥18 years) with ischemic stroke or TIA

Intervention

Clopidogrel resistance

Comparator

Non-resistant patients

Outcome

Sociodemographic, clinical, and genetic predictors of clopidogrel resistancesurrogate

Clopidogrel resistance in stroke/TIA patients is multifactorial, driven by older age, diabetes, poor glycemic control, female sex, non-smoking status, and genetic factors.

Main Result

Effect estimate: OR 1.55 (95% CI 1.22-1.97)

Abstract

Abstract Background and aims Clopidogrel resistance is prevalent in patients with ischemic stroke or transient ischemic attack (TIA), leading to recurrent cerebrovascular events. However, reported associations for its risk factors are inconsistent. This systematic review and meta-analysis quantifys the sociodemographic, clinical, and genetic predictors of clopidogrel resistance in patients with ischemic stroke or TIA. Methods Following PRISMA guidelines (PROSPERO: CRD420251113725), we systematically searched PubMed, Embase, Scopus, and Web of Science from inception to June 2025. Eligible studies included adults (≥18 years) with ischemic stroke or TIA reporting extractable data for clopidogrel-resistant and non-resistant groups. Results Sixty-five articles (11,786 patients) were included in this systematic review, of which 34 studies (6,053 patients) were included in the analysis. Compared with non-resistant patients, those with clopidogrel resistance were slightly older (MD 1.92 years; 95% CI 1.15–2.68) and had higher HbA1c (MD 0.27%; 95% CI 0.07–0.46), fasting blood glucose (MD 0.62 mmol/L; 95% CI 0.24–0.99), and total cholesterol (MD 0.09 mmol/L; 95% CI 0.004–0.18), but lower hemoglobin levels (MD −0.54 g/dL; 95% CI −1.04 to −0.04). While diabetes mellitus was associated with higher odds of resistance (OR 1.55; 95% CI 1.22–1.97), male sex (OR 0.75; 95% CI 0.65–0.86), current smoking (OR 0.74; 95% CI 0.56–0.97), and the CYP2C19 2 GG genotype (OR 0.45; 95% CI 0.26–0.78) were associated with lower odds of resistance. Conclusions Clopidogrel resistance in stroke/TIA patients is multifactorial, driven by a specific profile of demographic ( age, sex, smoking), metabolic (diabetes, glycemic control) and genetic (CYP2C19) factors. Conflict of interest Yusof M. Omar: Nothing to disclose, Abdullah Almarfadi: Nothing to disclose, Fawaz K Alfahmi: Nothing to disclose, Omar Hammam Salloum : Nothing to disclose, Jamal Ahmad: Nothing to disclose, Abdelrahman Abdelhameed Hashem: Nothing to disclose, Moamen Samy Syaj: Nothing to disclose, Omnia Samy El-Sayed : Nothing to disclose.

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