Does Long-Term Oxygen Help COPD Patients with Moderate Low Oxygen Levels?
No. This randomized trial of 738 COPD patients found that long-term supplemental oxygen did not lengthen the time to death or first hospitalization in patients with moderate oxygen desaturation. There was also no sustained benefit for quality of life, lung function, or walking distance.
For decades, doctors have prescribed oxygen therapy to COPD patients with moderately low oxygen levels, assuming it would help. This trial from the New England Journal of Medicine, the Long-Term Oxygen Treatment Trial, tested that assumption in patients with stable COPD and either moderate resting desaturation or moderate exercise-induced desaturation.
What the Data Show
LOTT followed 738 patients for 1 to 6 years:
- Death or first hospitalization: No significant difference between groups (hazard ratio 0.94, 95% CI 0.79 to 1.12, P=0.52)
- All hospitalizations: No difference (rate ratio 1.01, 95% CI 0.91 to 1.13)
- COPD exacerbations: No difference (rate ratio 1.08, 95% CI 0.98 to 1.19)
- COPD-related hospitalizations: No difference (rate ratio 0.99, 95% CI 0.83 to 1.17)
- Quality of life measures: No consistent between-group differences
- Lung function: No consistent between-group differences
- 6-minute walk distance: No consistent between-group differences
Dr. Kumar’s Take
This is one of the most important oxygen therapy trials published, and it challenges a long-standing habit of prescribing. The key distinction is between moderate and severe desaturation. The mortality benefit that drove oxygen into practice came from two trials in the 1970s in patients with severe resting hypoxemia, and those results led to the recommendation that supplemental oxygen be given at an oxygen saturation of less than 89%. What LOTT tells me is that I should not assume that benefit carries upward into patients whose saturation sits above that line.
Study Design
This was a parallel-group, multicenter randomized trial:
- 738 patients at 42 centers
- Two types of patients: Those with moderate resting desaturation (oxygen saturation 89 to 93%) and those with moderate exercise-induced desaturation
- Random assignment: 1:1 to long-term supplemental oxygen or no long-term supplemental oxygen, with group assignment not masked
- Follow-up: 1 to 6 years
- Oxygen prescription: 24-hour oxygen for resting desaturation, or exercise and sleep oxygen for exercise-induced desaturation
- Funding: National Heart, Lung, and Blood Institute and the Centers for Medicare and Medicaid Services
The trial was originally designed to test time to death in patients with moderate resting desaturation alone. After 7 months and the randomization of 34 patients, that design was judged infeasible because mortality was lower than projected and because patients with moderate resting desaturation overlapped phenotypically with those who desaturated on exertion. The investigators then expanded enrollment to include exercise-induced desaturation and folded hospitalization for any cause into a new composite primary outcome.
Why This Matters
Medicare reimbursements for oxygen-related costs in patients with COPD exceeded $2 billion in 2011. Reliable estimates of how many oxygen prescriptions are written specifically for exercise-induced desaturation are not available, and data suggest that many patients with advanced emphysema who are prescribed oxygen may not have severe resting hypoxemia. This trial suggests that some of that spending may not improve patient outcomes.
The trial protocol specified that the consistency of the treatment effect would be tested across subgroups defined by prespecified baseline characteristics.
Important Context
Two trials conducted in the 1970s showed that long-term supplemental oxygen reduced mortality in COPD patients with severe resting hypoxemia, and those results produced the recommendation to prescribe oxygen at a saturation below 89%. Two further trials in the 1990s tested long-term oxygen in COPD patients with mild-to-moderate daytime hypoxemia. Neither showed a mortality benefit, but both were underpowered to assess mortality. The effects of oxygen on hospitalization, exercise performance, and quality of life have remained unclear, which is the gap LOTT was built to close.
Practical Takeaways
- In patients with stable COPD and moderate resting or exercise-induced desaturation, long-term oxygen did not lengthen the time to death or first hospitalization
- The evidence supporting long-term oxygen remains in patients with severe resting hypoxemia, at a saturation below 89%
- Talk to your doctor about whether oxygen therapy is appropriate for your situation
Related Studies and Research
- Oxygen multistep therapy for sudden hearing loss
- Double-blind study on physical endurance (20 males)
- Athletic performance study
- Optimal hypoxic training for VO2max: Bayesian network meta-analysis
FAQs
Does this mean all oxygen therapy for COPD is useless?
No. The 1970s trials showed reduced mortality in patients with severe resting hypoxemia, and the recommendation built on them applies at a saturation of less than 89%. LOTT tested a different group: patients with moderate resting or exercise-induced desaturation.
What counts as moderate desaturation?
In this trial, moderate resting desaturation was an oxygen saturation of 89 to 93%. Moderate exercise-induced desaturation was defined during a 6-minute walk test as a saturation of 80% or higher for at least 5 minutes and below 90% for at least 10 seconds.
Should I stop using oxygen if I have moderate desaturation?
Talk to your doctor before making any changes. Individual circumstances vary, and your doctor can help determine what is right for you.
Bottom Line
The Long-Term Oxygen Treatment Trial found that prescribing long-term supplemental oxygen did not lengthen the time to death or first hospitalization in COPD patients with moderate resting or exercise-induced desaturation, and provided no sustained benefit in quality of life, lung function, or the distance walked in 6 minutes. The evidence for long-term oxygen still rests with patients whose saturation falls below 89%.
