Physical inactivity in chronic airways disease: an important candidate in the treatable traits paradigm

Physical inactivity is a common and potentially modifiable trait in individuals with chronic airways disease, yet disease-specific physical activity profiles and clinical determinants remain poorly defined.

We conducted a systematic review and meta-analysis in accordance with PRISMA guidelines to characterise physical activity profiles across the spectrum of chronic airways disease. Studies reporting objectively measured physical activity in adults with COPD, asthma, noncystic fibrosis bronchiectasis, cystic fibrosis or primary ciliary dyskinesia were included. Primary outcomes were daily step count and time spent in moderate-to-vigorous physical activity (MVPA). Univariate and multivariate regression analysis was used to explore disease-specific determinants and associations with established clinical outcome measures.

236 studies (353 cohorts, n=25 278 with chronic airways disease) met the eligibility criteria. The mean daily step count was 5494 (95% CI 5152-5636) and MVPA was 48.2 min·day^-1 (95% CI 33.8-62.6), with the lowest levels observed in COPD. Physical activity levels were consistently lower than matched healthy controls. Disease-specific determinants of physical activity remained elusive; body mass index and percent predicted forced expiratory volume in 1 s (FEV₁) were significant in COPD and asthma. Step count associated positively with FEV₁ % pred and 6-min walk distance, and negatively with modified Medical Research Council scores.

Physical inactivity is highly prevalent across chronic airways diseases and is consistently associated with established clinical outcome measures. These findings highlight the clinical relevance of objective physical activity assessment and support its consideration within the treatable traits framework as part of routine disease evaluation and management.