Controversy around long term oxygen in COPD

Long term oxygen therapy in COPD with significant hypoxia is well known to improve mortality. However, this randomised, non-blinded trial (NEJM 2016;375:1617–27) comparing long term oxygen therapy in COPD patients with moderate desaturation at rest (89–93%) to a non-masked matched group, published in the NEJM requires careful interpretation. The primary outcome (changed part way through the trial) was time to death or first hospitalisation. Only 738 patients were recruited with 368 assigned to the supplemental oxygen group and 370 to the control group. No significant difference was found between the two groups in mortality or time to hospitalisation, perhaps unsurprising given the nature of the intervention. Secondary endpoints, (arguably underpowered) including time to first exacerbation, rate of hospitalisation or quality of life also showed no statistically significant difference between the two groups. The authors conclude their …