title: No prognostic significance of chronic infection with Chlamydia pneumoniae in acute coronary syndromes: insights from the Global Utilization of Strategies to Open Occluded Arteries IV Acute Coronary Syndromes trial.
abstract: BACKGROUND
  Although relationships between chronic Chlamydia pneumoniae (Cpn) infection and the risk of coronary events in stable coronary artery disease patients have been reported, a similar link in acute coronary syndrome (ACS) patients has not been consistently observed.
  
  
  METHODS
  In a nested case-control substudy of the Global Utilization of Strategies to Open Occluded Arteries IV Acute Coronary Syndromes trial, 295 cases (30-day death/myocardial infarction [MI]) were matched by age, sex, baseline creatine kinase-myocardial kinase, and smoking status with 295 control subjects. To test the hypothesis on 1-year mortality, another subset (n = 276) was drawn from the 590-patient cohort; 138 patients who died at 1 year plus the matching controls who survived at 1 year. We measured Cpn IgG and IgA antibody titers in baseline serum with microimmunofluorescence. Conditional logistic regression was used to quantify the prognostic relevance seropositivity (IgG > or = 1:32; IgA > or = 1:16) and elevated titer levels.
  
  
  RESULTS
  The prevalence of Cpn IgG and IgA was similar between cases and controls (30-day death/MI: IgG, 80% vs 85%, P = .126; IgA, 45% vs 37%, P = .079), and were not statistically significant predictors of 30-day death/MI after baseline adjustment. Likewise, the 1-year death cohort had comparable proportions of Cpn IgG and IgA among cases and controls (86% vs 91% [P = .265] and 49% vs 43% [P = .334], respectively), and did not add prognostic value.
  
  
  CONCLUSIONS
  These findings are in concert with study results suggesting that chronic Cpn infection is not associated with 30-day death/MI or 1-year mortality in non-ST elevation ACS.
authors.affiliation: Heritage Medical Research Centre, University of Alberta, Edmonton, Alberta, Canada T6G 2S2. cindy.westerhout@ualberta.ca
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Westerhout
authors.forename: Judy
authors.initials: J
authors.lastname: Gnarpe
authors.forename: Wei-Ching
authors.initials: WC
authors.lastname: Chang
authors.forename: Susan
authors.initials: S
authors.lastname: FitzPatrick
authors.forename: Elliot S
authors.initials: ES
authors.lastname: Barnathan
authors.forename: Eric
authors.initials: E
authors.lastname: Boersma
authors.forename: Robert M
authors.initials: RM
authors.lastname: Califf
authors.forename: Lars
authors.initials: L
authors.lastname: Wallentin
authors.forename: Maarten L
authors.initials: ML
authors.lastname: Simoons
authors.forename: Paul W
authors.initials: PW
authors.lastname: Armstrong
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000453:epidemiology* / Q000209:etiology; D016022:Case-Control Studies; D023521:Chlamydophila Infections / Q000150:complications / Q000453:epidemiology* / Q000276:immunology; D016993:Chlamydophila pneumoniae; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000209:etiology; D015995:Prevalence; D011379:Prognosis
chemical_list: D007070:Immunoglobulin A; D007074:Immunoglobulin G