Psychometric properties of the Physical Activity Scale for the Elderly in Chinese patients with COPD

For patients with COPD, physical activity (PA) is recommended as the core component of pulmonary rehabilitation, but there is lack of a validated questionnaire for assessing the PA effectively.

To evaluate the reliability and validity of the Chinese version of Physical Activity Scale for the Elderly (PASE-C) in patients with COPD.

A cross-sectional study was conducted with 167 outpatients aged 60 years or older with COPD. Test-retest reliability and internal consistency were calculated by intraclass correlation coefficient (ICC) and Cronbach's coefficient α, respectively. Validity was evaluated by correlation with the International Physical Activity Questionnaire-Short (IPAQ-S), data of pedometer, Self-Efficacy for Managing Chronic Disease 6-Item Scale (SES6), Hospital Anxiety and Depression Scale (HADS), Medical Outcomes Study 36-Item Short Form Health Survey (SF-36), grip strength, and disease characteristics.

The PASE-C had an excellent seven-day test-retest reliability (ICC=0.98) and an acceptable internal consistency (Cronbach's α=0.71). The content validity was supported by an item-content validity index, a scale-content validity index/universal agreement, and a scale-content validity index/average value of 0.70-1, 0.70, and 0.93, respectively. Concurrent validity was tested by correlation with IPAQ-S (r=0.651). Criterion validity was confirmed by correlation with the walking steps (r=0.611) and energy expenditure (r=0.493). For construct validity, PASE-C had correlations with SES6 (r=0.396), HADS for depression (r=-0.234), seven subscales of SF-36 (r=0.182-0.525), grip strength (r=0.341), and disease characteristics including the duration of COPD (r=-0.215), modified British Medical Research Council scale (r=-0.354), forced expiratory volume in one second as percentage of predicted (r=0.307), and Global Initiative for Chronic Obstructive Lung Disease grade (r=-0.264), with a good construct validity (all P<0.05).

The PASE-C has acceptable reliability and validity for patients aged 60 years or older with COPD, and it can be used as a valid tool to measure the PA of patients with COPD in the People's Republic of China.