Exercise training for bronchiectasis

Abstract

Background: Bronchiectasis is characterised by excessive sputum production, chronic cough, and acute exacerbations and is associated with symptoms of dyspnoea and fatigue, which reduce exercise tolerance and impair quality of life. Exercise training in isolation or in conjunction with other interventions is beneficial for people with other respiratory diseases, but its effects in bronchiectasis have not been well established.

Objectives: To determine effects of exercise training compared to usual care on exercise tolerance (primary outcome), quality of life (primary outcome), incidence of acute exacerbation and hospitalisation, respiratory and mental health symptoms, physical function, mortality, and adverse events in people with stable or acute exacerbation of bronchiectasis.

Search methods: We identified trials from the Cochrane Airways Specialised Register, ClinicalTrials.gov, and the World Health Organization trials portal, from their inception to October 2020. We reviewed respiratory conference abstracts and reference lists of all primary studies and review articles for additional references.

Selection criteria: We included randomised controlled trials in which exercise training of at least four weeks' duration (or eight sessions) was compared to usual care for people with stable bronchiectasis or experiencing an acute exacerbation. Co-interventions with exercise training including education, respiratory muscle training, and airway clearance therapy were permitted if also applied as part of usual care.

Data collection and analysis: Two review authors independently screened and selected trials for inclusion, extracted outcome data, and assessed risk of bias. We contacted study authors for missing data. We calculated mean differences (MDs) using a random-effects model. We used the GRADE approach to assess the certainty of evidence.

Main results: We included six studies, two of which were published as abstracts, with a total of 275 participants. Five studies were undertaken with people with clinically stable bronchiectasis, and one pilot study was undertaken post acute exacerbation. All studies included co-interventions such as instructions for airway clearance therapy and/or breathing strategies, provision of an educational booklet, and delivery of educational sessions. The duration of training ranged from six to eight weeks, with a mix of supervised and unsupervised sessions conducted in the outpatient or home setting. No studies of children were included in the review; however we identified two studies as currently ongoing. No data were available regarding physical activity levels or adverse events. For people with stable bronchiectasis, evidence suggests that exercise training compared to usual care improves functional exercise tolerance as measured by the incremental shuttle walk distance, with a mean difference (MD) between groups of 87 metres (95% confidence interval (CI) 43 to 132 metres; 4 studies, 161 participants; low-certainty evidence). Evidence also suggests that exercise training improves six-minute walk distance (6MWD) (MD between groups of 42 metres, 95% CI 22 to 62; 1 study, 76 participants; low-certainty evidence). The magnitude of these observed mean changes appears clinically relevant as they exceed minimal clinically important difference (MCID) thresholds for people with chronic lung disease. Evidence suggests that quality of life improves following exercise training according to St George's Respiratory Questionnaire (SGRQ) total score (MD -9.62 points, 95% CI -15.67 to -3.56 points; 3 studies, 160 participants; low-certainty evidence), which exceeds the MCID of 4 points for this outcome. A reduction in dyspnoea (MD 1.0 points, 95% CI 0.47 to 1.53; 1 study, 76 participants) and fatigue (MD 1.51 points, 95% CI 0.80 to 2.22 points; 1 study, 76 participants) was observed following exercise training according to these domains of the Chronic Respiratory Disease Questionnaire. However, there was no change in cough-related quality of life as measured by the Leicester Cough Questionnaire (LCQ) (MD -0.09 points, 95% CI -0.98 to 0.80 points; 2 studies, 103 participants; moderate-certainty evidence), nor in anxiety or depression. Two studies reported longer-term outcomes up to 12 months after intervention completion; however exercise training did not appear to improve exercise capacity or quality of life more than usual care. Exercise training reduced the number of acute exacerbations of bronchiectasis over 12 months in people with stable bronchiectasis (odds ratio 0.26, 95% CI 0.08 to 0.81; 1 study, 55 participants). After an acute exacerbation of bronchiectasis, data from a single study (N = 27) suggest that exercise training compared to usual care confers little to no effect on exercise capacity (MD 11 metres, 95% CI -27 to 49 metres; low-certainty evidence), SGRQ total score (MD 6.34 points, 95%CI -17.08 to 29.76 points), or LCQ score (MD -0.08 points, 95% CI -0.94 to 0.78 points; low-certainty evidence) and does not reduce the time to first exacerbation (hazard ratio 0.83, 95% CI 0.31 to 2.22).

Authors' conclusions: This review provides low-certainty evidence suggesting improvement in functional exercise capacity and quality of life immediately following exercise training in people with stable bronchiectasis; however the effects of exercise training on cough-related quality of life and psychological symptoms appear to be minimal. Due to inadequate reporting of methods, small study numbers, and variation between study findings, evidence is of very low to moderate certainty. Limited evidence is available to show longer-term effects of exercise training on these outcomes.