Association of neutrophils and future cardiovascular events in patients with peripheral artery disease

Objective: We hypothesized that higher neutrophil counts are associated with an increased incidence of major adverse cardiovascular events (MACE) in patients with clinically advanced atherosclerosis. Methods: We prospectively studied 398 patients (233 men; median age, 69 years) with symptomatic peripheral artery disease who were admitted to the inpatient ward of the angiology department of a tertiary care university hospital in a cohort study. Total and differential white blood cell (WBC) counts were obtained, and patients were followed for MACE, defined as myocardial infarction, percutaneous coronary interventions, coronary artery bypass grafting, stroke, carotid revascularization, and death. Results: During a median follow-up of 20 months, 140 MACE occurred in 105 patients (26%). Multivariate Cox proportional hazards analysis was used to assess the association of differential WBC count parameters (in tertiles) with MACE and their interrelation with traditional cardiovascular risk factors and other parameters of inflammation. Patients with neutrophil counts > 5.8 G/L (upper tertile) exhibited an increased adjusted risk for all MACE (hazards ratio [HR], 1.83; P = .017), death (HR, 3.39; P = .010), and the composite of myocardial infarction, stroke, and death (HR, 2.20; P = .012) compared with patients in the lower tertile (< 4.4 G/L), independently of traditional cardiovascular risk factors and levels of high-sensitivity C-reactive protein. Only neurrophils, but not eosinophils, basophils, monocytes, lymphocytes, or the total WBC count showed a significant association with cardiovascular outcome. Conclusion: In patients with peripheral artery disease, neutrophil counts in the upper tertile (> 5.8 G/L) indicate a substantially increased risk for major adverse cardiovascular events, adding to the prognostic information of traditional atherothrombotic risk factors and other parameters of inflammation.