Validation of the Triaxial Accelerometer for the Evaluation of Physical Activity in Japanese Patients with COPD

Objective The quantification of physical activity is useful for the management of chronic obstructive pulmonary disease (COPD) but has not been fully established yet. The DynaPort Activity Monitor® (DAM), a triaxial accelerometer is the only well validated accelerometer in Caucasians but it has not been validated in Japanese COPD patients. We initially evaluated the reproducibility of the DAM in Japanese healthy subjects. Next, the within-subject repeatability and the determinants of physical activity were investigated in Japanese COPD patients. Materials and Methods The durations of locomotion, standing, and sitting measured by the DAM were compared to those of the self-records (Study 1). COPD patients wore the DAM for 3 days and the durations of each activity of 2 selected days were compared to assess the repeatability (Study 2). The relationship between the duration of locomotion and the physiological properties were examined (Study 3). Results The activities measured by the DAM were significantly associated with those of the self-records (p