Supplemental Oxygen No Help in Some Forms of COPD

Andrew Shorr, MD, MPH


May 02, 2017

This is Andy Shorr from the MedStar Washington Hospital Center with a pulmonary and critical care literature update. A crucial study about the use of supplemental oxygen in patients with advanced chronic obstructive pulmonary disease (COPD) was published in the New England Journal of Medicine by the Long-term Oxygen Treatment Trial Research Group.[1]

As pulmonologists, we prescribe oxygen to patients with hypoxemia at rest and potentially exertional desaturation (below saturations of 88%). This is based on clinical trials done some time ago; they certainly have limitations, but the standard seems to have held up to the challenge of time. In fact, Medicare uses that threshold for reimbursement of supplemental oxygen.

The question is, would a different standard be appropriate? If we call below 88% at rest "severe desaturation," what about patients with more moderate desaturations, such as those who had desaturations in the 89%-92% range, those with saturations at that level at rest, or patients who had exertional desaturations down to that level during a 6-minute walk test? This is what the trial tried to assess.

Patients with advanced COPD meeting those hypoxemia criteria—but not meeting the standard for needing supplemental oxygen based on the currently accepted criteria—were randomized to either supplemental oxygen or no therapy.

The trial was designed to look at the patients with resting hypoxemia in that moderate range. Huge delays in enrollment resulted in study design readjustment. Enrollment criteria were expanded to include those patients with moderate hypoxemia at rest or those with moderate desaturation during a 6-minute walk test. The specific criteria they used are illustrated in the manuscript.

The primary endpoint was a composite of either death or time to first hospitalization. These patients had substantially impaired quality of life and tended to be somewhat older than you would expect in the general COPD population because they had already progressed to having some kind of hypoxemia, just not severe hypoxemia.

Among the almost 740 patients from multiple centers across the United States, investigators saw no difference in any of their endpoints. There were no differences in secondary endpoints. The only subgroups where they saw significant differences were older patients—say, over 71 years—patients with a much worse quality of life than the rest of the cohort, and other groups of patients that were unique in different ways. Again, these are post-hoc, subgroup analyses that do not provide much insight and are only really hypothesis-generating for the future.

This study demonstrates quite conclusively that adding supplemental oxygen (even if to "make the patient feel better") beyond the criteria we have strictly adhered to for so many years, improves no outcome that is meaningful either to the healthcare system or to the patient.

These are good, confirmatory data from a well-done trial finding that we do not need to expand access to supplemental oxygen at this point.

This is Andy Shorr from Washington, DC.


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