title: [The research of establishing discriminant function for patients with angina pectoris by stepwise analysis based on serum inflammatory factors].
abstract: OBJECTIVE
  To improve cost-efficiency, discriminant functions in stepwise method was founded for the differential diagnosis of angina pectoris by detecting the serum level of high-sensitivity C-reactive protein (hs-CRP), macrophage migration inhibitory factor (MIF), interleukin-4 (IL-4) and interleukin-10 (IL-10) in patients with stable angina pectoris (SAP) and unstable angina pectoris (UAP).
  
  
  METHODS
  Thirty-nine SAP patients and 47 UAP patients were enrolled into the study, while 39 healthy volunteers were enrolled into the controlled group forming the entire set of training samples. The serum levels of hs-CRP, MIF, IL-4 and IL-10 were measured by enzyme linked immunosorbent assay (ELISA). Data was analyzed by software to define discriminant functions in the ways of "entering" and "stepwise". Both functions were evaluated by the results of validation.
  
  
  RESULTS
  By the way of "enter independent together", the following discriminant functions were defined based on the data of training samples' age, hs-CRP, MIF, IL-4, IL-10: healthy control group =-129.858 + 2.869×age -2.451×hs-CRP + 1.393×MIF + 6.001×IL-4 + 4.848×IL-10; SAP  group=-161.037 + 2.896×age-2.022×hs-CRP + 1.662×MIF + 6.703×IL-4 + 6.287×IL-10; UAP group=-199.087 + 2.468×age-1.440×hs-CRP + 3.404×MIF-13.875×IL-4 + 7.752×IL-10. Retrospective validation showed 4.8% of total miss-grouping, while cross-validation showed 5.6% of total miss-grouping. By the way of "stepwise", the above data was screened by software and  training  samples'  age, MIF and IL-10 were suggested to define the following functions: healthy control group = - 125.218 + 2.659 × age + 0.599×MIF + 5.040 × IL-10;  SAP  group=-157.864 + 2.721×age + 1.008×MIF + 6.468×IL-10; UAP group=- 197.327 + 2.360×age + 2.932×MIF + 7.640×IL-10. Both retrospective and cross validation showed 6.4% of total miss-grouping. Both sets of discriminant functions had the same efficiency (100%) for differential diagnosis of SAP and UAP.
  
  
  CONCLUSIONS
  The discriminant functions based on samples' age, MIF and IL-10, which were screened and suggested by stepwise method, may contribute to the differential diagnosis of atypical SAP and UAP, and therefore demonstrate better cost-efficiency.
authors.affiliation: Department of General Internal Medicine, the First Affiliated Hospital of SUN Yet-Sen University, Guangzhou 510080, Guangdong, China.
authors.forename: Zhi-bin
authors.initials: ZB
authors.lastname: Chen
authors.forename: Yan-bing
authors.initials: YB
authors.lastname: Liang
authors.forename: Hao
authors.initials: H
authors.lastname: Tang
authors.forename: Zhong-hua
authors.initials: ZH
authors.lastname: Wang
authors.forename: Li-jin
authors.initials: LJ
authors.lastname: Zeng
authors.forename: Jing-guo
authors.initials: JG
authors.lastname: Wu
authors.forename: Zhen-yu
authors.initials: ZY
authors.lastname: Li
authors.forename: Zhong-fu
authors.initials: ZF
authors.lastname: Ma
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000097:blood* / Q000145:classification / Q000175:diagnosis*; D002097:C-Reactive Protein / Q000378:metabolism*; D016022:Case-Control Studies; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D007249:Inflammation; D016753:Interleukin-10 / Q000097:blood*; D015847:Interleukin-4 / Q000097:blood; D019746:Intramolecular Oxidoreductases / Q000097:blood; D008263:Macrophage Migration-Inhibitory Factors / Q000097:blood; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: C508609:IL10 protein, human; C508598:IL4 protein, human; D008263:Macrophage Migration-Inhibitory Factors; D016753:Interleukin-10; D015847:Interleukin-4; D002097:C-Reactive Protein; D019746:Intramolecular Oxidoreductases; C515598:MIF protein, human