In patients with coronary artery disease undergoing PCI and receiving clopidogrel, baseline peripheral blood eosinophil count showed a dual association: a lower count was associated with an increased risk of high on-treatment platelet reactivity, whereas an elevated count was associated with an increased long-term risk of cardiac death.
Higher baseline eosinophil count was independently associated with a lower risk of high on-treatment platelet reactivity in clopidogrel-treated PCI patients.
Patients in the highest eosinophil quartile had lower odds of high on-treatment platelet reactivity than those in the lowest quartile.
The dose-response relationship between eosinophil count and high on-treatment platelet reactivity was linear and negative.
The inverse association between eosinophil count and high on-treatment platelet reactivity was consistent across clinical subgroups.
Higher baseline eosinophil count was independently associated with higher risk of 5-year cardiac death.
Patients in the highest eosinophil quartile had about twice the risk of cardiac death compared with the lowest quartile.
Baseline eosinophil count showed a dual association, with low counts linked to high platelet reactivity and elevated counts linked to long-term cardiac death.
This study followed 6,524 people with coronary artery disease who had a stent-type procedure (PCI) at one Chinese hospital and took aspirin plus clopidogrel, a blood-thinning drug. Researchers looked at whether the number of eosinophils (a type of white blood cell) in the blood before the procedure was related to how well clopidogrel worked, and to death from heart causes over five years. People with lower eosinophil counts were more likely to have high on-treatment platelet reactivity, meaning their platelets were still quite active despite clopidogrel. The relationship was steady across the range of counts and held across groups defined by age, sex, diabetes, high blood pressure, type of coronary syndrome, body weight, and inflammation level. In contrast, people with higher eosinophil counts were more likely to die of heart causes over five years: 140 of 6,050 followed patients (2.31%) did, and those in the highest quartile had roughly double the risk of those in the lowest. This research suggests eosinophil count, a routine and inexpensive blood test, may carry information about both clopidogrel response and long-term heart outcomes. However, this is an observational study from a single center, so it shows associations rather than cause and effect, and it does not show that changing eosinophil levels or treatment would improve outcomes.
Ke Z, Yan K, Yuan D, Zhang K, Liu M, Xu F, et al.. (2026). [Dual association of peripheral blood eosinophil count with high on-treatment platelet reactivity and long-term cardiac death in patients with coronary artery disease: a large-scale cohort study].. Zhonghua xin xue guan bing za zhi. https://doi.org/10.3760/cma.j.cn112148-20260313-00166