Mortality, exacerbations, hospitalisations and quality of life were unaffected.

Long-term oxygen therapy lowers short-term mortality in patients with chronic obstructive pulmonary disease (COPD) and severe hypoxaemia, but benefits for those with moderate hypoxaemia are less clear. In this meta-analysis, researchers pooled data from six randomised trials of long-term oxygen therapy in patients with COPD and moderate hypoxaemia (defined as hypoxaemia without oxygen saturations of 88% or below and without isolated nocturnal hypoxaemia). Studies of long-term oxygen therapy in patients with purely exertional hypoxaemia were excluded. In total, 1000 patients who received oxygen therapy for an average of seven to 14 hours daily or usual care were included.

Patients who received oxygen therapy and usual-care patients had similar three-year mortality, incidence of acute COPD exacerbations and respiratory hospitalisations, and quality-of-life scores. Serious adverse events, including burns and tripping over oxygen equipment, were rare (less than one per 100 person-years), but adverse events were reported in only two trials.

Comment: This study highlights the lack of evidence for benefit of long-term oxygen therapy in patients with COPD and moderate hypoxaemia and does not support routine use of home oxygen in this population. Important limitations were that patients who were randomised to oxygen therapy used it for less than the 15 to 18 hours daily that was targeted in trials of oxygen therapy for severe hypoxaemia and lack of information on subgroups of patients who might benefit from oxygen therapy. Note: Of the trials included in this meta-analysis, the two largest and most recent ones were summarised in NEJM Journal Watch (NEJM JW Gen Med Nov 1 2020 and N Engl J Med 2020; 383: 1129-1138; NEJM JW Gen Med Dec 1 2016 and N Engl J Med 2016; 375: 1617-1627).

Rahul B. Ganatra, MD, MPH
Instructor in Medicine, Harvard Medical School; Director of Continuing Medical Education for the Medical Service, VA Boston Healthcare System, Boston, USA.

Lacasse Y, et al. Home oxygen for moderate hypoxaemia in chronic obstructive pulmonary disease: a systematic review and meta-analysis. Lancet Respir Med 2022; 10: 1029-1037.

This summary is taken from the following Journal Watch titles: General Medicine, Ambulatory Medicine, Hospital Medicine