Xiang 2007.

Methods	Randomised, parallel controlled study
Participants	40 people with COPD
Interventions	Nocturnal‐NIPPV and long‐term oxygen therapy versus long‐term oxygen therapy alone for 2 years
Outcomes	BGA, lung function, dyspnoea, 6MWD, respiratory muscle score, mortality, hospital admissions, dropout rate, anxiety scores
Notes	The article was written in Chinese. This study probably meets the review eligibility criteria, but verifying how the study was conducted based on the English information available was not possible as authors did not respond to clarify important issues

6MWD: 6‐minute walking distance; BGA: blood gas analysis; COPD: chronic obstructive pulmonary disease; NIPPV: non‐invasive positive pressure ventilation.