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

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 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 CVDmortality 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 53 ± 10 years) performed a sub-maximal step test on two occasions to estimate the criterion measure of cardio-respiratory fitness (V̇O 2max). A further maximal cycling test provided a direct fitness measurement (V̇O2 peak). 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 V̇O 2max correlated well with directly measured V̇O2 peak