Stop Prescribing Nocturnal Oxygen to Patients With COPD

The Centers for Medicare & Medicaid Services (CMS) currently covers nocturnal oxygen for patients with COPD whose oxygen saturation is < 88% for more than 5 nonconsecutive minutes during sleep. As a practicing pulmonary and sleep physician, I've always considered this a very low bar to meet. Studies in elderly patients (age > 60 years) without COPD show a median oxygen nadir of 88%-89% during sleep, which implies that a substantial number of patients with COPD will qualify for nocturnal oxygen if we screen them with overnight oximetry.

In 2018, a review published in the American Journal of Respiratory and Critical Care Medicine recommended against ordering supplemental nocturnal oxygen for patients with COPD who meet CMS criteria. They noted that three small, randomized trials failed to show any meaningful benefit from nocturnal oxygen supplementation. The review authors concluded that they were anxiously awaiting publication of the larger randomized controlled International Nocturnal Oxygen (INOX) trial, investigating the efficacy of nocturnal oxygen supplementation for patients with COPD.

Well, the INOX trial was just published. A short summary? The findings were negative. Over a period of 4 years, providing nocturnal oxygen to patients with saturation < 90% for at least 30% of total sleep time resulted in no tangible benefits.

The primary outcome was a composite of all-cause mortality and requirement for long-term oxygen supplementation during the day. Secondary outcomes included adherence, exacerbations, quality of life, and hospitalizations. The study was well conducted, adherence was tracked, and time on oxygen was recorded. Nocturnal oxygen therapy did not affect any of the primary or secondary outcomes.

Unfortunately, the trial was stopped early due to recruitment issues, so it ended up being underpowered. The authors attempted to make up for this by combining the INOX trial results with findings from two other randomized controlled trials and summarizing the outcomes data. No benefit from nocturnal oxygen supplementation was found; however, even when combining studies, they still only had a total of 306 patients.

While a benefit from nocturnal oxygen supplementation has not been conclusively excluded, the evidence against it is mounting.

There are those who would argue that the physiologic impact from correcting hypoxia is self-evident and doesn't need to be proven. They might also say that oxygen won't do any harm and CMS pays for it, so why shouldn't we order it for our patients? Pulmonologists get to feel like they're doing something, and our patients think we're advocating for them.

Let's not forget, though, that over 1 million Medicare recipients are prescribed long-term oxygen therapy at an annual cost of $2 billion. Aggressive screening for nocturnal hypoxia would drive these numbers up even more. Physicians should know that if we're not selective when prescribing expensive therapies, the insurance industry will choose for us. No doubt we will complain about their restrictive policies, but we'll have only ourselves to blame.

Everything we know about nocturnal and ambulatory oxygen supplementation tells us that it doesn't help our patients with COPD. Pulmonologists, please don't waste time ordering overnight oximetry studies, and stop prescribing nocturnal oxygen therapy.

Aaron B. Holley, MD, is an associate professor of medicine at Uniformed Services University and program director of pulmonary and critical care medicine at Walter Reed National Military Medical Center. He covers a wide range of topics in pulmonary, critical care, and sleep medicine.

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