title: Fluctuating inflammatory markers in patients with stable ischemic heart disease.
abstract: BACKGROUND
  C-reactive protein (CRP), a marker of inflammation, is increasingly measured to stratify coronary artery disease risk and guide clinical management. However, little is known about how inflammatory markers fluctuate over time in patients with stable ischemic heart disease.
  
  
  METHODS
  We examined serial serum CRP values in 159 patients with histories spanning the clinical spectrum of ischemic heart disease. Two to 8 CRP measurements were made at intervals varying from 15 days to 6 years. Successive interleukin (IL)-6 values were examined in 1 subgroup. Blood samples were always taken when patients were clinically stable, in the absence of any potentially confounding inflammatory condition.
  
  
  RESULTS
  C-reactive protein values in individual patients fluctuated considerably when examined in the following ranges: less than 1 mg/L, 1 to 3 mg/L, and greater than 3 mg/L, proposed to indicate low, average, and high risk. Sixty-four patients (40.3%) changed risk category between the first and the second measurement. Within-patient variances of CRP and IL-6 levels were 1.79 mg/L (95% confidence interval, 1.60-2.00) and 2.69 pg/mL (95% confidence interval, 2.29-3.18), respectively. The variability of CRP was consistent over different times and across clinical groups, and independent of body mass index, smoking status, medication, and clinical events.
  
  
  CONCLUSIONS
  Relatively important fluctuations in CRP levels in patients with stable ischemic heart disease may be problematic for risk stratification and treatment monitoring. A similar IL-6 variability suggests that these patients have a dynamic inflammatory status whose kinetics may modulate acute coronary risk.
authors.affiliation: Quebec Heart Institute, Laval Hospital, Laval University, Quebec City, Quebec, Canada. peter.bogaty@med.ulaval.ca
authors.forename: Peter
authors.initials: P
authors.lastname: Bogaty
authors.forename: James M
authors.initials: JM
authors.lastname: Brophy
authors.forename: Luce
authors.initials: L
authors.lastname: Boyer
authors.forename: Serge
authors.initials: S
authors.lastname: Simard
authors.forename: Lawrence
authors.initials: L
authors.lastname: Joseph
authors.forename: Fernand
authors.initials: F
authors.lastname: Bertrand
authors.forename: Gilles R
authors.initials: GR
authors.lastname: Dagenais
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D000789:Angina, Unstable / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D002097:C-Reactive Protein / Q000032:analysis*; D002316:Cardiotonic Agents / Q000627:therapeutic use; D004562:Electrocardiography; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy; D017202:Myocardial Ischemia / Q000097:blood* / Q000175:diagnosis* / Q000188:drug therapy; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D002316:Cardiotonic Agents; D018836:Inflammation Mediators; D002097:C-Reactive Protein