Reproducibility and Sensitivity of the 6-Minute Stepper Test in Patients with COPD

• Published in: Chronic obstructive pulmonary disease Vol. 12; no. 5; pp. 533 - 538
• Main Authors: Coquart, Jérémy B., Lemaître, Frédéric, Castres, Ingrid, Saison, Sylvain, Bart, Frédéric, Grosbois, Jean-Marie
• Format: Journal Article
• Language: English
• Published: New York Informa Healthcare 03.09.2015; Taylor & Francis
• Subjects: Aged; Bias; Dyspnea - etiology; Exercise Test - methods; exercise text; Exercise Therapy; Female; field test; Forced Expiratory Volume; functional capacity; Heart Rate; Human health and pathology; Humans; Life Sciences; Male; Middle Aged; Physical Exertion; Pulmonary Disease, Chronic Obstructive - complications; Pulmonary Disease, Chronic Obstructive - physiopathology; Pulmonary Disease, Chronic Obstructive - rehabilitation; pulmonary rehabilitation; reliability; Reproducibility of Results; Time Factors; Tissues and Organs; Treatment Outcome; Vital Capacity; exercise text; field test; functional capacity; pulmonary rehabilitation; reliability
• ISSN: 1541-2555; 1541-2563
• DOI: 10.3109/15412555.2014.974733

The aims of this study were to test the reproducibility of the 6-minute stepper test (6MST), and evaluate its accuracy in detecting improved functional capacity after pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD). Thirty-five COPD outpatients performed two 6MSTs in the same session, before (6MST 1 and 6MST 2 ) and after (6MST 3 and 6MST 4 ) PR. The performance, perceived exertion, heart rate and arterial oxygen saturation were measured during each 6MST. The performance was higher during the second 6MST of the same session (before PR: 514 strokes during the 6MST 2 > 471 strokes during the 6MST1, and after PR: 559 strokes during the 6MST 4 > 508 strokes during the 6MST 3 ; p = 0.04). After PR, 6MST performance was higher than before PR (6MST 3 > 6MST 1 and 6MST 4 > 6MST 2 ; P < 0.01). The bias (the difference in the number of strokes) between the two 6MSTs from the same session (before PR: 6MST 2 -6MST 1 = 42 strokes vs after PR: 6MST 4 -6MST 3 = 52 strokes) was not different (P = 0.34). However, both bias were greater than 0 (P < 0.001). The mean performances for the two 6MSTs of the same session (before PR: 6MST 1 and 6MST 2 and after PR: 6MST 3 and 6MST 4 ) were correlated with the bias between these performances (P < 0.01; r = 0.32). The perceived exertions were lower after PR (P < 0.02). The systematic improvement of performance (8-10%) during the second 6MST of the each session may be explained from the warming of hydraulic jacks of the stepper and/or learning effect. On the other hand, the 6MST seems sufficiently sensitive to detect functional capacity improvements after PR in patients with COPD.