• COPD exacerbations
• COPD epidemiology
• imaging/CT MRI etc
• pulmonary rehabilitation
• respiratory muscles

While airflow limitation is used to diagnose chronic obstructive pulmonary disease (COPD), it is well established that forced expiratory volume in one second alone relates poorly to mortality1 or health-related quality of life.2 Skeletal muscle dysfunction has been shown to be a better predictor than lung function for both prognosis3 and risk of hospitalisation.4 Moreover, skeletal muscle weakness is increasingly recognised as an important component of both frailty and sarcopaenia. Acute exacerbations of COPD (AECOPD) are a feature of many patients with COPD, with intermittent worsening of symptoms contrasting to many other chronic conditions. The impact of exacerbations is well established, with prevention and treatment an important goal for therapy with COPD.

Therefore, the interaction between exacerbations and skeletal muscle dysfunction is of great interest. A reduction in both exercise capacity and quadriceps strength has been reported in patients admitted with acute exacerbation of COPD5 and to a lesser extent among patients treated as an outpatient6 but the longer-term impact on muscle mass is unknown. Similarly, how therapies such as pulmonary rehabilitation (PR) may impact on future exacerbations risk in the longer term is less clear, although the short-term benefits of this therapy after AECOPD are established.7

In this issue of Thorax, Mason et al 8 report an association between exacerbation frequency and accelerated muscle loss in patients with COPD. …