title: Arterial age as a substitute for chronological age in the AGLA risk function could improve coronary risk prediction.
abstract: BACKGROUND
  As a result of the relatively low sensitivity of coronary risk charts, such as the Swiss coronary risk calculator (Arbeitsgruppe Lipide und Atherosklerose, AGLA), for detecting subjects with future myocardial infarction, the performance of arterial age (aa) as a surrogate marker for chronological age (ca) was tested.
  
  
  METHODS
  In a practice based sample, burden of carotid plaque was obtained with ultrasound, using total plaque area (TPA). In this derivation cohort, sex-specific 5-year groups of mean TPA were calculated in subjects aged between 35 and 79 years. The arterial age formula was found by fitting an exponential function on these data. AGLAca and AGLAaa were tested externally for their ability to detect 13 myocardial infarctions in 684 subjects (validation cohort).
  
  
  RESULTS
  The derivation cohort included 1,500 subjects (mean age 59 ± 9 years, mean TPA 54 ± 52 mm2, 5% diabetics, 43% women). Arterial age was found to be y = 5.4175e0.0426x in men and y = 4.1942e0.0392x in women. Mean 10-year AGLAca coronary risk was comparable to AGLAaa (8% ± 9% vs 9% ± 15%). Receiver operating characteristic (ROC) analysis of AGLAca and AGLAaa results showed areas under the curve of 0.65 (p = 0.041) and 0.78 (p <0.0001), respectively, (p = 0.041 for the difference = 0.13). This finding was also confirmed by a Cox proportional hazards regression model on patients' event-free survival (p = not significant for AGLAca, p = 0.0003 for AGLAaa).
  
  
  CONCLUSIONS
  Arterial age derived from TPA could be used instead of chronological age in the AGLA coronary risk function. Further studies on the external validity and cost effectiveness of the additional ultrasound imaging study are necessary.
authors: Vascular Risk Foundation, Olten, Switzerland.
authors: Michel
authors: M
authors: Romanens
authors: Olten, Switzerland.
authors: Franz
authors: F
authors: Ackermann
authors: Cardiovascular Centre Cardiology, University Hospital, Zurich, Switzerland.
authors: Isabella
authors: I
authors: Sudano
authors: European Centre of Pharmaceutical Medicine (ECPM), Basel, Switzerland.
authors: Thomas
authors: T
authors: Szucs
authors: Stroke Prevention & Atherosclerosis Research Centre, Robarts Research Institute, Western University, London, Canada.
authors: J David
authors: JD
authors: Spence
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D019540:Area Under Curve; D002342:Carotid Artery, External / Q000000981:diagnostic imaging* / Q000502:physiology; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging* / Q000502:physiology; D059168:Carotid Intima-Media Thickness; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D008297:Male; D055641:Mathematical Concepts; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012372:ROC Curve; D018570:Risk Assessment / Q000379:methods