Long-awaited results from a study conducted among COPD patients with moderate oxygen deficiency who were and were not treated with long-term oxygen therapy are now in, and the take home message for respiratory therapists and other clinicians is this: in this group of patients, home oxygen does not result in longer life, shorter time to first hospitalization, or improvement in quality of life.
“The benefits of long-term oxygen supplements for COPD patients with severe oxygen deficiency are clear,” says corresponding author Robert Wise, MD, from Johns Hopkins University School of Medicine. “However, it’s never been established what benefits, if any, exist for patients with less severe oxygen deficiency.”
This study, published this week by The New England Journal of Medicine, is the largest to date to look at that aspect.
No differences seen
In addition to Dr. Wise, the study involved a range of investigators from 42 clinical centers in the U.S., including such well-known names to the respiratory therapy profession as Richard Casaburi, MD, of the University of California at Los Angeles Medical Center; Steven E. Gay, MD, of the University of Michigan; and Neil MacIntyre, MD, FAARC, of Duke University Medical Center.
Moderate oxygen deficiency was defined as having a resting blood oxygen saturation between 89-93%, or a blood oxygen saturation below 90% during a six-minute walk test. One hundred and thirty-three patients had resting oxygen deficiency, 319 had exercise-induced oxygen deficiency, and 268 had both. The 738 patients with moderate oxygen deficiency were randomly assigned to supplemental oxygen (368 patients) or no supplemental oxygen (370 patients)
All of the participants underwent annual assessments that included oxygen levels at rest and exercise, oxygen use, respiratory symptoms, and quality of life. They also completed telephone interviews biannually and mailed questionnaires regarding symptoms and health care use at four and 16 months. The study was conducted between 2009 and 2015.
The risk of death in the no-oxygen group was 5.7% per year vs. 5.2% per year in the oxygen group. No significant differences were seen in hospitalization rates, COPD exacerbations, self-reported quality of life, lung function, or measures of walk distance. The findings held true even when researchers controlled for variables such as total hours of oxygen use, race, sex, and smoking status.
The results are clear
“No matter what measure we looked at, it made no apparent difference whether a patient with moderate oxygen deficiency received long-term oxygen treatments or not,” says Dr. Wise. “I think the evidence is strong and shows that some patients may not need those treatments at all.”
That said, Dr. Wise is quick to note that patients who use supplemental oxygen should consult their physician before discontinuing the therapy.
“We don’t want to imply that everyone with COPD now using oxygen should stop; some individual patients may find that they can do more activities or have more effective exercise training if they use oxygen,” he cautions. “Every patient should discuss his or her specific needs with his or her health care provider, but the data show, very clearly, that for many COPD patients with moderately low blood oxygen levels, supplemental oxygen won’t help you live any longer or keep you out of the hospital.”