title: Evaluation of red blood cell distribution width in patients with cardiac syndrome X.
abstract: BACKGROUND
  Cardiac syndrome X (CSX) is a condition characterized by chest pain with normal coronary arteries. However, its pathogenesis has not fully been understood yet. Red blood cell distribution width (RDW) has recently been suggested as a marker of acute and chronic cardiovascular diseases, while no data is available in patients with CSX.
  
  
  METHODS
  One hundred and twenty consecutive patients with CSX and 102 normal controls were prospectively enrolled in this study. Blood samples were drawn from all individuals for measuring RDW and high-sensitivity C-reactive protein (CRP). The baseline data were compared between patients with CSX and normal controls.
  
  
  RESULTS
  The RDW levels were significantly higher in patients with CSX than that in those with normal controls (13.1 ± 2.1 versus 12.3 ± 1.8, p=0.011). Moreover, the data showed that the levels of plasma CRP were marked higher in patients with CSX than those that were observed in normal controls (CRP: 2.8 ± 2.2 mg/L versus 2.0 ± 1.7 mg/dl, p=0.014). In addition, the multivariate analysis indicated that peripheral monocyte cell, CRP and RDW were the independent variables most strongly associated with CSX. In a receiver operating characteristic (ROC) curve analysis, we found that an RDW value of 12.8% was used as an effective cut-point in the segregation of the presence or absence of cardiac syndrome X, a sensitivity of 52.0% and a specificity of 65.4% were obtained. Finally, correlation analysis suggested that there was positive correlation between plasma levels of CRP and RDW levels (n=120, γ =0.381, P=0.013).
  
  
  CONCLUSIONS
  The present study, for the first time, demonstrated that elevated RDW and CRP levels were independently associated with the presence of CSX.
authors.affiliation: Division of Dyslipidemia, State Key Laboratory of Cardiovascular Disease, Fu Wai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Qing
authors.forename: Song-Hui
authors.initials: SH
authors.lastname: Luo
authors.forename: Yuan-Lin
authors.initials: YL
authors.lastname: Guo
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Rui-Xia
authors.initials: RX
authors.lastname: Xu
authors.forename: Cheng-Gang
authors.initials: CG
authors.lastname: Zhu
authors.forename: Yan-Jun
authors.initials: YJ
authors.lastname: Jia
authors.forename: Feng-Lian
authors.initials: FL
authors.lastname: Ma
authors.forename: Na-Qiong
authors.initials: NQ
authors.lastname: Wu
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Jiang
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Li
mesh_terms: D000328:Adult; D002097:C-Reactive Protein / Q000032:analysis; D016022:Case-Control Studies; D004909:Erythrocyte Indices; D005260:Female; D006801:Humans; D008297:Male; D017566:Microvascular Angina / Q000097:blood* / Q000175:diagnosis; D008875:Middle Aged
chemical_list: D002097:C-Reactive Protein