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Reproducibility of the ambulatory arterial stiffness index in patients with type 1 diabetes mellitus

Laugesen, Esbena; Hansen, Klavs W.b; Knudsen, Søren T.a b; Erlandsen, Mogensc; Ebbehøj, Evad; Poulsen, Per L.a

doi: 10.1097/MBP.0b013e32833531f9
Analytical and Statistical Methods

Objectives: 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.

Conclusion: 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.

aMedical Department M (Diabetes and Endocrinology), Aarhus University Hospital

bMedical Department, Regional Hospital Silkeborg

cDepartment of Biostatistics, University of Aarhus

dMedical Department C, Aarhus University Hospital, Denmark

Correspondence to Esben Laugesen, MD, Medical Department M (Diabetes and Endocrinology), Aarhus University Hospital, Noerrebrogade, DK-Aarhus C, Denmark

Tel: +45 8949 9959; fax: +45 8949 2010;

e-mail: esbenlaugesen@hotmail.com

Received 23 June 2009 Revised 8 September 2009 Accepted 28 September 2009

© 2010 Lippincott Williams & Wilkins, Inc.