Long-term Oxygen Treatment Does Not Benefit Some COPD Patients

Study addresses long-standing question for those with moderately low blood oxygen levels.

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“For the most part, this treatment did not improve or prolong life in study participants.”

James P. Kiley, Ph.D., Director, NHLBI, Division of Lung Diseases

Newly published data from the Long-Term Oxygen Treatment Trial (LOTT) show that oxygen use is not beneficial for most people with chronic obstructive pulmonary disease (COPD) and moderately low levels of blood oxygen. It neither boosted their survival nor reduced hospital admissions for study participants. Previous research showed that long-term oxygen treatment improves survival in those with COPD and severely low levels of blood oxygen. However, a long-standing question remained whether a different group of COPD patients — those with moderately low levels of blood oxygen—also benefit. The study was funded by the National Heart, Lung, and Blood Institute (NHLBI) — a part of the National Institutes of Health—and the Centers for Medicare & Medicaid Services.

The study, the largest of its kind to evaluate the effectiveness of home oxygen in this group of patients, is published in the current online issue of the New England Journal of Medicine.  The 738 patients enrolled in this study had COPD and moderately low levels of blood oxygen (in contrast to severely low blood oxygen levels) at rest or during exercise.

In the current study, patients with moderately low levels of blood oxygen are defined as those with a blood oxygen saturation (SpO2) between 89 and 93 percent at rest (moderate resting hypoxemia), or a SpO2 below 90 percent during the 6-minute walk test.  Patients with severely low blood oxygen levels are defined as those with a SpO2 equal to or less than 88 percent at rest. This latter group was excluded from the LOTT study because prior studies showed that they benefit from long-term oxygen treatment.  Blood oxygen saturation or SpO2 refers to the percentage of oxygen-saturated hemoglobin relative to total hemoglobin in the blood and is measured through a pulse oximeter. A pulse oximeter is a special probe that indirectly measures oxygen levels in the blood, often by attachment to the finger.

“These results provide insight into a long-standing question about oxygen use in patients with COPD and moderately low levels of blood oxygen. For the most part, this treatment did not improve or prolong life in study participants,” said James P. Kiley, Ph.D., director of NHLBI’s Division of Lung Diseases. “The findings also underscore the need for new treatments for COPD.”

Researchers say patients with any form of COPD should check with their doctors before making changes in their treatment plans. “We want to make it clear that LOTT was not designed to assess individual responses to oxygen treatment and that individual responses can vary. Each COPD patient should discuss their own personal situation with their healthcare provider,” said William C. Bailey, M.D., Professor Emeritus at the University of Alabama at Birmingham School of Medicine, and study Chair.

COPD, the third leading cause of death in the United States, is a progressive lung disease triggered primarily by cigarette smoking, although up to 20 percent of patients with COPD never smoked. Symptoms include shortness of breath, chronic coughing, and wheezing. The disease also causes low oxygen levels in the blood. About 15 million people have been diagnosed with COPD in the United States and another 10 million may be undiagnosed.

For decades, oxygen has been one of the main treatment tools for patients with COPD and low oxygen levels. It involves the use of metal tank cylinders containing oxygen or concentrators that extract oxygen from air; both systems deliver the gas through a nasal tube or mask.

The LOTT study is a randomized clinical trial to determine whether oxygen use could help COPD patients with moderately low levels of blood oxygen.  The seven-year study, which included patients from 42 medical centers throughout the United States, began in 2009 and was completed in 2015.

In the study, half of the patients received long-term oxygen and the other half did not. The researchers found no significant differences between the two groups based on how long patients survived, and the amount of time leading to their first hospitalization. They also found no differences in other important benchmarks, such as the rates at which the patients were hospitalized or experienced worsening of COPD symptoms. Nor did researchers find statistically significant differences between the groups in quality of life, levels of depression or anxiety, lung function, or ability to walk for short periods.

Although no cure for COPD exists, there are a number of treatment options, including the use of bronchodilators and steroids, as well as pulmonary rehabilitation, surgery, and lung transplantation. Researchers worldwide are also studying new medications and exploring other approaches such as gene therapy. They continue to emphasize the importance of not smoking tobacco in preventing or slowing the progression of COPD.