title: Reproducibility of the ambulatory arterial stiffness index in patients with type 1 diabetes mellitus.
abstract: OBJECTIVE
  The ambulatory arterial stiffness index (AASI) has been proposed as a novel indirect measure of arterial stiffness. We compared the repeatability of AASI and pulse pressure (PP), another marker of arterial stiffness, both computed from repeat 24-h ambulatory blood pressure recordings in patients with type 1 diabetes mellitus.
  
  
  METHODS
  Twenty-eight patients with type 1 diabetes mellitus and no previous or present treatment with antihypertensive drugs were recruited from outpatient clinics in Aarhus County and underwent two 24-h ambulatory blood pressure measurements, performed within 2 weeks in all participants except one. The repeatability of AASI and PP was assessed by (i) the Intraclass Correlation Coefficient (ICC) and (ii) the percentage of maximal variation, i.e. two times SD of the difference in the percentage of four times the SD of the mean of the paired measurements.
  
  
  RESULTS
  The repeatability of AASI was considerably lower than for PP as estimated by ICC (0.38 vs. 0.90). The difference between ICCPP and ICCAASI was 0.51 confidence interval (0.25-0.82). Similarly, percentage of maximal variation was 68 and 23% respectively.
  
  
  CONCLUSIONS
  AASI has a low repeatability compared with PP in type 1 diabetic patients. This questions the potential implementation of AASI in the daily clinic as a measure of arterial stiffness. Further studies are necessary to clarify this.
authors.affiliation: Medical Department M (Diabetes and Endocrinology), Aarhus University Hospital, Denmark. esbenlaugesen@hotmail.com
authors.forename: Esben
authors.initials: E
authors.lastname: Laugesen
authors.forename: Klavs W
authors.initials: KW
authors.lastname: Hansen
authors.forename: Søren T
authors.initials: ST
authors.lastname: Knudsen
authors.forename: Mogens
authors.initials: M
authors.lastname: Erlandsen
authors.forename: Eva
authors.initials: E
authors.lastname: Ebbehøj
authors.forename: Per L
authors.initials: PL
authors.lastname: Poulsen
mesh_terms: D000328:Adult; D001158:Arteries / Q000503:physiopathology; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000592:standards*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012015:Reference Standards; D015203:Reproducibility of Results; D055815:Young Adult