Sample size calculation would have been overinflated; re-think study design

This trial hopes to demonstrate the effect of 4 weeks of outpatient exercise rehabilitation on COPD patients. In particular the effect on:

• the amount of daily physical activity
• Quality of life
• The 6-minute walk distance
• Time to exacerbation

and compare it to the effect of 4 weeks of outpatients rehabilitation with Noninvasive Ventilation as an adjunct therapy.

Inclusion Criteria:

• Diagnosis of COPD III+IV
• Age >18 years
• Former NIV treatment for at least 6 weeks with a positive end-expiratory pressure of at least 4 cmH2O and a pressure support of 8 cmH2O or higher

Exclusion Criteria:

• Pulmonary Exacerbation requiring antibiotic treatment or hospitalization during the last 6 weeks
• non-pulmonary Exercise impairment (amputation, severe heart disease, etc)
• any disease that precludes exercise training
• inability to understand the patient information
• substance abuse
• oxygen requirement of more than 6l O2/min during exercise