Chronic respiratory failure following an acute exacerbation of COPD is associated with excess morbidity and mortality1 and, empirically, the use of long-term non-invasive ventilation (NIV) to treat the chronic respiratory failure to improve outcome is a rational therapeutic option. Although detailed physiological studies have demonstrated a reduction in the arterial pCO₂ by managing sleep disordered breathing and enhancing sleep quality, previous randomised controlled trials have failed to translate physiological improvement into a clinical benefit.2–4 Despite the lack of clinical trial evidence supporting the addition of NIV to standard treatment, including long-term oxygen therapy,5 ,6 there has remained widespread clinical enthusiasm in the UK and Europe for the use of home mechanical ventilation (HMV) for the treatment of COPD in patients with hypercapnic respiratory failure.7 The largest RCT of HMV in stable hypercapnic COPD patients, published previously in the journal, reported a limited mortality benefit.6 This trial only randomised 144 patients instead of an intended 200, due to the challenges in recruitment of these sick COPD patients with advanced disease. There was no difference in 2-year mortality, the primary outcome, however, a survival difference was apparent with data adjustment for important baseline variables such as pCO₂, arterial pO₂ and health-related quality of life (HRQL). Of major clinical relevance in terms of cost effectiveness, this mortality advantage had to be offset by the detrimental effect of the intervention on HRQL.

Although there are currently limited data to support the clinical and cost effectiveness of NIV in patients with COPD, it must be highlighted that these data have provided detailed insight, which have been useful in the development of further trials. Indeed, we must consider that the failure of NIV to enhance the clinical outcome in COPD patients with chronic respiratory failure is …