title: The association between white blood cell count and acute myocardial infarction mortality in patients > or =65 years of age: findings from the cooperative cardiovascular project.
abstract: OBJECTIVE
  The purpose of the study was to examine the association between white blood cell (WBC) count on admission and 30-day mortality in patients with acute myocardial infarction (AMI).
  
  
  BACKGROUND
  Elevations in WBC count have been associated with the development of AMI and with long-term mortality in patients with coronary artery disease. However, the relationship between WBC count and prognosis following AMI is less clear.
  
  
  METHODS
  Using the Cooperative Cardiovascular Project database, we evaluated 153,213 patients > or = 65 years of age admitted with AMI.
  
  
  RESULTS
  An increasing WBC count is associated with a significantly higher risk of in-hospital events, in-hospital mortality and 30-day mortality. Relative to those patients in the lowest quintile, patients in the highest quintile were three times more likely to die at 30 days (10.3% vs. 32.3%; p < 0.001). After adjustment for confounding factors, WBC count was found to be a strong independent predictor of 30-day mortality (odds ratio = 2.37; 95% confidence interval 2.25 to 2.49, p = 0.0001 for the highest quintile of WBC count).
  
  
  CONCLUSIONS
  White blood cell count within 24 h of admission for an AMI is a strong and independent predictor of in-hospital and 30-day mortality as well as in-hospital clinical events. Although the mechanism of the association remains speculative, the results of this study have important clinical implications for risk-stratifying patients with AMI.
authors.affiliation: Department of Epidemiology and Biostatistics and Medicine (Cardiology), University of California, San Francisco, San Francisco, California, USA.
authors.forename: H V
authors.initials: HV
authors.lastname: Barron
authors.forename: S D
authors.initials: SD
authors.lastname: Harr
authors.forename: M J
authors.initials: MJ
authors.lastname: Radford
authors.forename: Y
authors.initials: Y
authors.lastname: Wang
authors.forename: H M
authors.initials: HM
authors.lastname: Krumholz
mesh_terms: D000368:Aged; D016009:Chi-Square Distribution; D016208:Databases, Factual; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007958:Leukocyte Count; D016015:Logistic Models; D008297:Male; D009203:Myocardial Infarction / Q000097:blood* / Q000401:mortality*; D011237:Predictive Value of Tests; D012307:Risk Factors