title: Baseline white blood cell count is an independent predictor of long-term cardiovascular mortality in patients with non-ST-segment elevation acute coronary syndrome, but it does not improve the risk classification of the GRACE score.
abstract: OBJECTIVE
  To investigate the prognostic significance of baseline white blood cell count (WBCc) in non-ST-segment elevation acute coronary syndrome (NSTE-ACS) and its additive predictive value beyond the Global Registry of Acute Coronary Events (GRACE) score.
  
  
  METHODS
  We included 1,315 consecutive NSTE-ACS patients. Patients were divided in quartiles according to the WBCc (cells per 1 mm(3)) i.e. Q1 <6,850, Q2 = 6,850-8,539, Q3 = 8,540-10,857 and Q4 ≥10,858. The study end point was 3-year cardiovascular death (CVD).
  
  
  RESULTS
  The median age of the study population was 76 years. Overall, 335 patients (25.5%) died with 211 of these (16%) suffering from CVD. Patients in Q4 showed a higher cumulative probability of CVD compared to patients in Q1-Q3. On multivariable analysis, patients in Q4 were at higher risk of CVD [hazard ratio (HR) = 1.47, 95% confidence interval (CI) 1.09-1.98, p = 0.011]. WBCc as a continuous variable was also independently associated with the study end point (HR = 1.043; 95% CI 1.02-1.07; p = 0.001). However, the incorporation of WBCc into the GRACE score did not improve either prediction of risk (C-index = 0.796 for GRACE score with or without WBCc) or classification of risk [relative integrated discrimination improvement = 0.0154, 95% CI) -0.029 to 0.0618; continuous net reclassification improvement = -0.0676, 95% CI -0.2149-0.0738).
  
  
  CONCLUSIONS
  WBCc was an independent predictor of 3-year CVD in patients with NSTE-ACS. However, it did not add prognostic information beyond the GRACE score.
authors: Institute of Cardiology, St. Orsola/Malpighi Hospital, Bologna University, Bologna, Italy. neviotaglieri@hotmail.it
authors: Nevio
authors: N
authors: Taglieri
authors: Maria Letizia
authors: ML
authors: Bacchi Reggiani
authors: Tullio
authors: T
authors: Palmerini
authors: Laura
authors: L
authors: Cinti
authors: Francesco
authors: F
authors: Saia
authors: Paolo
authors: P
authors: Guastaroba
authors: Cinzia
authors: C
authors: Marrozzini
authors: Carolina
authors: C
authors: Moretti
authors: Michela
authors: M
authors: Montefiori
authors: Stefania
authors: S
authors: Rosmini
authors: Laura
authors: L
authors: Alessi
authors: Fabio
authors: F
authors: Vagnarelli
authors: Angelo
authors: A
authors: Branzi
authors: Claudio
authors: C
authors: Rapezzi
authors: Antonio
authors: A
authors: Marzocchi
mesh_terms: D054058:Acute Coronary Syndrome / Q000401:mortality*; D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000401:mortality; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D007958:Leukocyte Count; D008297:Male; D011379:Prognosis; D018570:Risk Assessment / Q000379:methods