An original field evaluation test for chronic obstructive pulmonary disease population: the six-minute stepper test

The aim of this study was to evaluate a new field test, the six-minute stepper test (6-MST), by studying its reproducibility, sensitivity and validity.

After a familiarization test, 16 patients with chronic obstructive pulmonary disease (COPD) and 15 healthy subjects performed two six-minute stepper tests per day over three evaluation days. Ten of the 16 patients with COPD also performed a six-minute walking test (6-MWT) with an analysis of gas exchange to compare the metabolic requirements of the two tests. Dyspnoea Borg values were evaluated with Borg's CR-10 scale.

The mean (SD) scores for the COPD group for the first and second six-minute stepper tests were 382.49 (106.01) and 412.45 (118.39) strokes/6 minutes, respectively. Crossed comparison between the first or the second six-minute stepper tests of each evaluation day revealed no significant difference, indicating the reproducibility of the test. The sensitivity was demonstrated by a significantly higher performance in the healthy group (P < 0.001), demonstrating the ability of the test to detect two groups with different fitness levels. Finally, mean dyspnoea Borg values (SD) were significantly lower (P < 0.05) during the six-minute stepper test than during 6-MWT (2.5 (1.5) versus 3.1 (1.2)).

This study demonstrated that the six-minute stepper test is a reproducible, sensitive, secure, well-tolerated and feasible test for patients with COPD. The reproducibility and sensitivity of the six-minute stepper test suggests that this test could be used in the evaluation of exercise tolerance in patients with COPD.