1.
Objectively Measured Physical Activity as a COPD Clinical Trial Outcome.
Burtin, C, Mohan, D, Troosters, T, Watz, H, Hopkinson, NS, Garcia-Aymerich, J, Moy, ML, Vogiatzis, I, Rossiter, HB, Singh, S, et al
Chest. 2021;(6):2080-2100
Abstract
BACKGROUND Reduced physical activity is common in COPD and is associated with poor outcomes. Physical activity is therefore a worthy target for intervention in clinical trials; however, trials evaluating physical activity have used heterogeneous methods. RESEARCH QUESTION What is the available evidence on the efficacy and/or effectiveness of various interventions to enhance objectively measured physical activity in patients with COPD, taking into account the minimal preferred methodologic quality of physical activity assessment? STUDY DESIGN AND METHODS In this narrative review, the COPD Biomarker Qualification Consortium (CBQC) task force searched three scientific databases for articles that reported the effect of an intervention on objectively measured physical activity in COPD. Based on scientific literature and expert consensus, only studies with ≥ 7 measurement days and ≥ 4 valid days of ≥ 8 h of monitoring were included in the primary analysis. RESULTS Thirty-seven of 110 (34%) identified studies fulfilled the criteria, investigating the efficacy and/or effectiveness of physical activity behavior change programs (n = 7), mobile or electronic-health interventions (n = 9), rehabilitative exercise (n = 9), bronchodilation (n = 6), lung volume reduction procedures (n = 3), and other interventions (n = 3). Results are generally variable, reflecting the large differences in study characteristics and outcomes. Few studies show an increase beyond the proposed minimal important change of 600 to 1100 daily steps, indicating that enhancing physical activity levels is a challenge. INTERPRETATION Only one-third of clinical trials measuring objective physical activity in people with COPD fulfilled the preset criteria regarding physical activity assessment. Studies showed variable effects on physical activity even when investigating similar interventions.
2.
Exercise and muscle dysfunction in COPD: implications for pulmonary rehabilitation.
Man, WD, Kemp, P, Moxham, J, Polkey, MI
Clinical science (London, England : 1979). 2009;(8):281-91
Abstract
Skeletal muscle dysfunction in COPD (chronic obstructive pulmonary disease) patients, particularly of the quadriceps, is of clinical interest because it not only influences the symptoms that limit exercise, but may also contribute directly to poor exercise performance and health status, increased healthcare utilization, and mortality. Furthermore, unlike the largely irreversible impairment of the COPD lung, skeletal muscles represent a potential site to improve patients' level of function and quality of life. However, despite expanding knowledge of potential contributing factors and greater understanding of molecular mechanisms of muscle wasting, only one intervention has been shown to be effective in reversing COPD muscle dysfunction, namely exercise training. Pulmonary rehabilitation, an intervention based on individually tailored exercise training, has emerged as arguably the most effective non-pharmacological intervention in improving exercise capacity and health status in COPD patients. The present review describes the effects of chronic exercise training on skeletal muscles and, in particular, focuses on the known effects of pulmonary rehabilitation on the quadriceps muscle in COPD. We also describe the current methods to augment the effects of pulmonary rehabilitation and speculate how greater knowledge of the molecular pathways of skeletal muscle wasting may aid the development of novel pharmaceutical agents.