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International Journal of Rheumatology
Volume 2013, Article ID 174541, 8 pages
http://dx.doi.org/10.1155/2013/174541
Clinical Study

A Simple Step Test to Estimate Cardio-Respiratory Fitness Levels of Rheumatoid Arthritis Patients in a Clinical Setting

1School of Sport, Health and Exercise Sciences, Bangor University, George Building, Bangor, Gwynedd LL57 2PZ, UK
2School of Medical Sciences, Bangor University, Brigantia Building, Penrallt Road, Bangor, Gwynedd LL57 2AS, UK
3Department of Rheumatology, Betsi Cadwaladr University Health Board (West), Llandudno General Hospital, Llandudno LL30 1LB, UK
4Institute of Clinical and Biomedical Science, Medical School, University of Exeter, Exeter EX1 2LU, UK

Received 30 July 2013; Revised 22 October 2013; Accepted 31 October 2013

Academic Editor: Malcolm Smith

Copyright © 2013 Jennifer K. Cooney et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. Exercise tests represent an important clinical tool to evaluate cardio-respiratory fitness and to predict future adverse cardiovascular events. However, use of such tests in patients with rheumatoid arthritis (RA) is relatively uncommon despite well-established evidence that low exercise capacity and high CVD mortality are features of this disease. Therefore, this study examined the validity and reliability of a sub-maximal step test for use in RA patients. Methods. Thirty patients (24 females) (mean ± SD age years) performed a sub-maximal step test on two occasions to estimate the criterion measure of cardio-respiratory fitness ( ). A further maximal cycling test provided a direct fitness measurement ( ). Pearson correlation coefficient, intraclass correlation coefficient (ICC), Bland and Altman plots, and 95% limits of agreement (LOA) were used to determine the validity and reliability of the sub-maximal test. Results. Estimated correlated well with directly measured ( , LoA ±5.7 mL·kg−1·min−1). Test-retest reproducibility for estimated was excellent ( , LoA ±2.2 mL·kg−1·min−1). Conclusion. The sub-maximal step test studied here represents a valid and reproducible method to estimate cardio-respiratory fitness in RA patients. This test may be useful for the assessment and management of CVD risk in a clinical setting.