Which White Blood Cell Subtypes Predict Increased Cardiovascular Risk?

OBJECTIVES: We sought to determine the predictive ability of total white blood cell (WBC) count and its subtypes for risk of death or myocardial infarction (MI). BACKGROUND: An elevated WBC count has been associated with cardiovascular risk, but which leukocyte subtypes carry this risk is uncertain. METHODS: Consecutive patients without acute MI who were assessed angiographically for coronary artery disease (CAD) and were followed up long-term were studied. The predictive ability for death/MI of quartile (Q) 4 versus Q1 total WBC, neutrophil (N), lymphocyte (L), and monocyte (M) counts and N/L ratio were assessed using Cox regressions. RESULTS: A total of 3,227 patients was studied. Mean age was 63 years; 63% of patients were male, and 65% had CAD. In multivariable modeling entering standard risk factors, presentation, and CAD severity, the total WBC (hazard ratio HR 1.4, p = 0.01) and M (HR 1.3, p 6.6 x 10(3)/microl) or low L counts. The greatest risk prediction is given by the N/L ratio, with Q4 versus Q1 (>4.71 versus <1.96) increasing the hazard 2.2-fold. These findings have important implications for CAD risk assessment.