Reproducibility of step tests in patients with bronchiectasis

Background: The step test has been used to assess exercise capacity in patients with chronic respiratory disease; however, its use has not been described with regard to patients with bronchiectasis (BCT). Objective: This study assessed the reliability of the Chester step test (CST) and the modified incremental step test (MIST) and also correlated these tests with pulmonary function, heart rate (HR), and distance walked during the 6-min walk test (6-MWT). Method: On separate days, 17 patients randomly underwent two CSTs, two MISTs, and two 6-MWTs. Number of steps (NOSs), HR, and perceived exertion were recorded immediately before and after these tests. Results: NOSs were similar across CSTs (124±65 and 125±67) and MISTs (158±83 and 156±76). Differences were not found across the CSTs and MISTs with regard to HR (138±25 bpm and 136±27 bpm), SpO₂ (91±5% and 91±3%), perceived exertion (dyspnea=4 [3-5] and 4 [2-4.5]) and fatigue (4 [2-6] and 4 [3-5]). The CST was significantly briefer than the MIST (6.0±2.2 min and 8.6±3.0 min) and had fewer associated NOS (125±67 and 158±83). NOSs were correlated with FEV1, the 6-MWD, and HR for both tests. Conclusions: The CST and MIST are reliable in patients with BCT. Patients tolerated the MIST more than the CST. Better lung function and 6-MWT scores predicted the greater NOSs and greater peak HR.