The PROactive instruments to measure physical activity in patients with chronic obstructive pulmonary disease

Abstract

No current patient-centred instrument captures all dimensions of physical activity in chronic obstructive pulmonary disease (COPD). Our objective was item reduction and initial validation of two instruments to measure physical activity in COPD.Physical activity was assessed in a 6-week, randomised, two-way cross-over, multicentre study using PROactive draft questionnaires (daily and clinical visit versions) and two activity monitors. Item reduction followed an iterative process including classical and Rasch model analyses, and input from patients and clinical experts.236 COPD patients from five European centres were included. Results indicated the concept of physical activity in COPD had two domains, labelled “amount” and “difficulty”. After item reduction, the daily PROactive instrument comprised nine items and the clinical visit contained 14. Both demonstrated good model fit (person separation index >0.7). Confirmatory factor analysis supported the bidimensional structure. Both instruments had good internal consistency (Cronbach's α>0.8), test–retest reliability (intraclass correlation coefficient ≥0.9) and exhibited moderate-to-high correlations (r>0.6) with related constructs and very low correlations (r<0.3) with unrelated constructs, providing evidence for construct validity.Daily and clinical visit “PROactive physical activity in COPD” instruments are hybrid tools combining a short patient-reported outcome questionnaire and two activity monitor variables which provide simple, valid and reliable measures of physical activity in COPD patients.

Physical Activity as a Predictor of Absence of Frailty in Subjects With Stable COPD and COPD Exacerbation

“…14 COPD has been reported 15 to be related to reduction in peripheral muscle performance and functional capacity on the clinical course of the disease. Impaired functional capacity 16 and physical activity levels 17 have been identified as predictors of hospitalization for COPD patients, and the loss of muscle strength has been related to the increased utilization of health-care resources. 18 Additionally, the natural course of COPD includes frequent exacerbations 19 that are associated with impaired lung function and a reduction in muscle strength, endurance, and physical activity levels.…”

Interventions to modify physical activity in patients with COPD: where do we go from here?

“…In order to capture all dimensions of physical activity during these interventions it has been recommended to combine the objective assessment of physical activities with a short and validated patient-reported outcomes questionnaire focusing on the difficulties of performing physical activities related to symptoms [1]. It has become evident that, besides functional capacity and symptoms experienced during activity, behavioural and environmental factors are also related to participation in daily physical activity in patients with COPD [13].…”

Can health status questionnaires be used as a measure of physical activity in COPD patients?

“…This leads to the hypothesis that symptoms can depend on the physical activity level and, therefore, fail to give a reliable estimate of the actual underlying physical activity level. Indeed, patients' perception of physical activity includes not only the amount of physical activity but also symptoms experienced during and adaptations related to physical activity [9,14].…”

“…Patients were current or ex-smokers (⩾10 pack-years) without comorbidities significantly interfering with their ability to exercise and without respiratory conditions other than COPD. Further study details are available in the article reporting the primary analyses of the present study [9]. Physical activity was measured for 14 days during waking hours using the Dynaport Movemonitor (McRoberts, The Hague, the Netherlands), which has been validated in this population [10,11].…”