Correlation Comparison and Personalized Utility of Field Walking Tests in Assessing the Exercise Capacity of Patients with Chronic Obstructive Pulmonary Disease: A Randomized Controlled Trial

Background: Incremental shuttle walking tests (ISWT) are regarded as valuable alternatives to 6-min walking tests (6MWT) and cardiopulmonary exercise tests (CPET) owing to the maximal and externally paced loading. This study investigated the validity and reliability of ISWT by analyzing the correlation of the distances of two field tests with peak oxygen consumption (VO(2)) of CPET in patients with COPD. Methods: In this randomized controlled trial, patients with COPD were enrolled from two hospitals. Three assessments were performed for all patients. The ISWT and 6MWT were repeated twice in Hospital 1 to assess reliability. Results: A total of 29 patients were enrolled. The distances of ISWT (0.782, p < 0.001) and 6MWT (0.512, p = 0.005) correlated with peak VO(2). The intraclass correlation coefficients of both ISWT (0.988, p < 0.001) and 6MWT (0.959, p < 0.001) was high. Patients with higher peak VO(2) walked a longer distance in ISWT than 6MWT (r = 0.590, p < 0.001). Conclusions: The ISWT more highly correlates with peak VO(2) than the 6MWT and has excellent reliability in patients with COPD. According to peak VO(2), the walking distances of each field test varied, suggesting that the application should be personalized for the exercise capacity.