Objectively measured physical activity as a COPD clinical trial outcome.

Abstract

BACKGROUND\nReduced 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 methodologies.\n\n\nRESEARCH QUESTION\nWhat 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 minimal preferred methodological quality of physical activity assessment?\n\n\nSTUDY DESIGN AND METHODS\nIn 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 hours of monitoring were included in the primary analysis.\n\n\nRESULTS\n37 of 110 (34%) identified studies fulfilled the criteria, investigating the efficacy and/or effectiveness of physical activity behavior change programs (n=7), mobile health or eHealth 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 variation in study characteristics and outcomes. Few studies show an increase beyond the proposed minimal important change of 600-1100 daily steps, indicating that enhancing physical activity levels is a challenge.\n\n\nINTERPRETATION\nOnly a third of clinical trials measuring objective physical activity in people with COPD fulfilled the pre-set criteria regarding physical activity assessment. Studies showed variable effects on physical activity even when investigating similar interventions.