title: Ankle brachial index and intima media thickness predict cardiovascular events similarly and increased prediction when combined.
abstract: OBJECTIVE
  To compare the predictive value of the ankle brachial index (ABI) and carotid intima media thickness (IMT) for cardiovascular events.
  
  
  METHODS
  Population-based cohort study. New cardiovascular events (myocardial infarction [MI], stroke, angina, and intermittent claudication) were ascertained over a 12-year period in 1,007 men and women aged 60-79 and free of MI or stroke.
  
  
  RESULTS
  The positive and negative predictive values for an ABI<or=0.9, an IMT>or=0.9mm and for both tests abnormal were not substantially different. However, event rates in subjects with one test normal were increased when the alternate test proved positive (in people with a normal ABI test, 20.8% with an abnormal IMT developed MI/stroke compared with only 10.3% with a normal IMT). The area under the receiver operator curves (AUC) increased significantly between a model containing only age and sex (AUC 0.60, 95% confidence interval [CI] 0.55, 0.65) and that with either ABI (AUC 0.63, 95% CI 0.58, 0.69, P=0.002) or IMT (AUC 0.62, 95% CI 0.57, 0.67, P=0.005) added. The AUC increased further when both tests were added simultaneously (AUC 0.65, 95% CI 0.60, 0.70, P<0.001).
  
  
  CONCLUSIONS
  The ability of the ABI to predict cardiovascular disease was similar to that of the IMT. Combination of the two tests may be advantageous when the second test is applied to people with a negative first test and/or when the results are used as continuous variables.
authors: Wolfson Unit for Prevention of Peripheral Vascular Diseases, Division of Community Health Sciences, University of Edinburgh, Teviot Place, Edinburgh EH8 9AG, UK. Jackie.Price@ed.ac.uk
authors: Jackie F
authors: JF
authors: Price
authors: Ioanna
authors: I
authors: Tzoulaki
authors: Amanda J
authors: AJ
authors: Lee
authors: F Gerald R
authors: FG
authors: Fowkes
mesh_terms: D000368:Aged; D000842:Ankle / Q000098:blood supply; D050197:Atherosclerosis / Q000150:complications / Q000175:diagnosis; D001916:Brachial Artery / Q000503:physiopathology*; D002318:Cardiovascular Diseases / Q000209:etiology*; D002339:Carotid Arteries / Q000000981:diagnostic imaging / Q000473:pathology*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology; D011379:Prognosis; D020521:Stroke / Q000209:etiology; D017539:Tunica Intima / Q000000981:diagnostic imaging / Q000473:pathology; D017540:Tunica Media / Q000000981:diagnostic imaging / Q000473:pathology; D014463:Ultrasonography