title: The predictive value of the borderline ankle-brachial index for long-term clinical outcomes: An observational cohort study.
abstract: Low ankle-brachial index (ABI) is associated with increased mortality and an increased incidence of cardiovascular events. The purpose of this study was to investigate the value of borderline ABI in predicting clinical outcomes.
  
  
  
  The data were derived from the Shinken Database 2004-2012, from a single hospital-based cohort study (N = 19,994). ABI was measured in 5205 subjects; 4756 subjects whose ABI was 0.91-1.39 and having no history of peripheral artery disease were enrolled. The subjects were classified into two groups as follows: borderline ABI (0.91-1.00; n = 324) and normal ABI (1.01-1.39; n = 4432). Subjects in the borderline ABI group had more comorbidities, including diabetes mellitus, aortic disease, and stroke. Moreover, the borderline ABI group was associated with higher levels of hemoglobin A1c and brain natriuretic peptide, larger diameters of left atrium and left ventricle, and lower levels of estimated glomerular filtration rate and left ventricular ejection fraction. All-cause death and cardiovascular death occurred in 9.3% and 4.6% of subjects in the borderline ABI group, and in 2.0% and 0.8% of subjects in the normal ABI group, respectively. An adjusted Cox regression model showed that borderline ABI was associated with a higher incidence of all-cause death (hazard ratio [HR] 2.27, p = 0.005) and cardiovascular death (HR 3.47, p = 0.003).
  
  
  
  A borderline ABI was independently associated with worse clinical outcomes in relatively high risk population. Our data should be confirmed in larger populations including those with low risk profiles.
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan. Electronic address: shingo.tanaka.123@gmail.com.
authors.forename: Shingo
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Kaneko
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Kano
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Matsuno
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Shinya
authors.initials: S
authors.lastname: Suzuki
authors.affiliation: Department of Cardiovascular Surgery, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takai
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Otsuka
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Tokuhisa
authors.initials: T
authors.lastname: Uejima
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Oikawa
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Nagashima
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Kirigaya
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Sagara
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Junji
authors.initials: J
authors.lastname: Yajima
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Sawada
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Tadanori
authors.initials: T
authors.lastname: Aizawa
authors.affiliation: Department of Cardiovascular Medicine, The Cardiovascular Institute, 3-2-19, Nishiazabu, Minato-ku, Tokyo 106-0031, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamashita
mesh_terms: D000368:Aged; D055109:Ankle Brachial Index; D016208:Databases, Factual; D003920:Diabetes Mellitus / Q000175:diagnosis* / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000378:metabolism; D006325:Heart Atria / Q000473:pathology; D006352:Heart Ventricles / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D058729:Peripheral Arterial Disease / Q000453:epidemiology*; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012042:Registries; D016896:Treatment Outcome
chemical_list: D006442:Glycated Hemoglobin; D020097:Natriuretic Peptide, Brain; C517652:hemoglobin A1c protein, human
keywords: Ankle-brachial index; Borderline; Peripheral arterial disease; Prognosis