Predictive value of white blood cell subtypes for long-term outcome following myocardial infarction

Elevation of total white blood cells (WBC) count is associated with higher mortality in patients with acute coronary syndromes. However, it is unknown which specific subset of leukocytes best correlates with increased risk of adverse outcome.

We prospectively studied the predictive value of WBC subtypes for long-term outcome in 1037 patients with acute myocardial infarction (AMI). Total WBC, neutrophil, monocyte and lymphocyte counts, and high-sensitivity C-reactive protein (CRP) were obtained in each patient. The median duration of follow up was 23 months (range, 6-42 months). Analyzed separately, baseline total WBC (HR 2.2, 95% CI 1.5-3.3; P<0.0001), neutrophil (HR 2.7, 95% CI 1.8-4.1; P<0.0001) and monocyte (HR 1.9, 95% CI 1.3-2.8; P=0.001) counts in the upper quartile, and lymphocyte count in the lower quartile (HR 1.5, 95% CI 1.1-2.3; P=0.03), were all independent predictors of mortality. Comparing nested models, adding other WBC data failed to improve model based on neutrophil count. In contrast, adding neutrophil count to the models based on total WBC (P=0.01), on monocyte count (P<0.0001) or on lymphocyte count (P<0.0001) improved the prediction of the models. Neutrophil count in the upper quartile (>or=9800 microL(-1)) remained a strong independent predictor of mortality after adjustment for left ventricular systolic function and for CRP (HR 2.2, 95% CI 1.6-3.0; P<0.0001).

Of all WBC subtypes, elevated neutrophil count best correlates with mortality in patients with AMI. Neutrophil count provides additive prognostic information when combined with CRP.