Utilizing a daily physical activity monitor to reflect physical function, symptoms, and quality of life in patients with hypoxic COPD

Abstract

Background: Physical activity in patients with severe hypoxic chronic obstructive pulmonary disease (COPD) is highly affected. As a result, their quality of life is also affected negatively. Widely used tools to measure physical activity in COPD include exercise tolerance tests such as endurance shuttle walk tests and six-minute walk tests. However, these tests have limitations and do not reflect the complete picture of an individual’s physical activity. This led to the development of the Clinical version of PROactive Physical Activity in COPD (C-PPAC) tool which uses objective and subjective data to reflect patients’ experience of physical activity. However, the relationship between the C-PPAC tool and physical activity measures, quality of life measures, and COPD characteristics on patients within the severe hypoxic COPD group has not been fully explored.

Methods: This study employed a cross-sectional design. Patients with severe hypoxic COPD using either long term oxygen therapy or ambulatory oxygen therapy have been recruited. All participants had to attend two visits, seven days apart. Physical activity was measured using the incremental shuttle walk test (ISWT) and the C-PPAC tool. Quality of life was measured using COPD specific patient reported outcome measures. COPD characteristics such as severity and dyspnoea were also collected. Regression analyses were employed to investigate the relationship between the C-PPAC total score, physical activity, quality of life, COPD severity and dyspnoea.

Results: 11 patients were recruited and completed all the assessment, 45.5% were males (n= 5). The ISWT distance has a statistically insignificant positive relationship with the C-PPAC Total Score (r= 0.509) with a p-value= 0.161. There is a statistically insignificant positive relationship between the C-PPAC total score and the quality of life measures (r=0.823) with a p-value= 0.106. The COPD severity and dyspnoea have a statistically significant positive linear relationship with the C-PPAC total score (r= 0.959) with a p-value of 0.004.

Conclusion: This study examined the relationship between the C-PPAC total score and various factors related to COPD, including physical activity, health-related quality of life, and COPD characteristics. The findings showed a moderate positive relationship between the C-PPAC total score and the ISWT distance, a strong relationship with the quality of life measures, and a very strong relationship with COPD characteristics. A higher C-PPAC score is related to a higher ISWT distance, better quality of life, lower dyspnoea, and higher FEV1 results. Although the study is underpowered, the results indicate that the C-PPAC tool may be useful for capturing physical activity experience in people with severe hypoxic COPD.