Purpose: To determine whether long-term oxygen treatment is beneficial for group of people with chronic obstructive pulmonary disease (COPD) and moderately low levels of blood oxygen.
Background: COPD is the third leading cause of death in the United States, affecting an estimated 15 million Americans. Millions more do not even know that they have the disease. The progressive lung disease, which makes it difficult to breathe, is triggered primarily by cigarette smoking. However, up to 20 percent of patients with COPD never smoked. Other risk factors include environmental exposure to lung irritants and genetic predisposition.
Past research has shown that long-term oxygen treatment improves survival in those with COPD and severely low levels of blood oxygen. However, a long-standing question remains whether a different group—those with moderately low levels of blood oxygen—also benefits.
Design: A randomized, multicenter clinical trial.
Primary Outcomes: Death or hospitalization.
Secondary Outcomes: Disease-specific quality of life, preference-weighted health-related quality of life, quality-adjusted survival, health care utilization, maintenance of nutritional status (e.g., body mass index), general quality of life, sleep quality, depression and anxiety, onset of severe hypoxemia (defined as room air oxygen saturation less than or equal to 88%) , 6-minute walk distance, dyspnea (shortness of breath), COPD exacerbation rate, adherence to supplemental oxygen, risk of cardiovascular disease, cost effectiveness.
Participants: 738 participants with COPD and moderately low levels of blood oxygen (in contrast to severely low blood oxygen levels) at rest or during exercise. The LOTT study group represented a diverse group of men and women with COPD. Average age was about 69 years. About 74 percent were male; about 87 percent of enrollees were Caucasian. African-Americans represented about 11 percent of the study population; Hispanics represented about 2 percent. All of the participants were current (27 percent) or former smokers.
Enrollment: The study enrollment began in January 2009 and was completed in September 2015 at 42 clinical sites in the United States.
Treatment Arms: The treatment arms included the experimental group, who received supplemental oxygen therapy, and the “no intervention” group, who did not receive supplemental oxygen therapy. Those in the “no intervention” group did not receive oxygen unless the participant met conventional Medicare criteria for supplemental oxygen during the course of the study. Of the 738 total patients studied, 368 received supplemental oxygen and 370 did not.
Initial Study Results: The LOTT study demonstrated that long-term oxygen use is not beneficial for most people with COPD and moderately low levels of blood oxygen. It neither boosted their survival nor reduced hospital admissions for study participants. The study found no overall differences in important benchmarks, such as the rates at which the patients were hospitalized or experienced worsening of COPD symptoms. Nor did researchers find consistent differences between the groups in quality of life, levels of depression or anxiety, lung function, or ability to walk for short periods. Even when researchers controlled for variables such as total hours of oxygen use, race, sex and smoking status, no significant differences in the primary outcomes arose.
Action Taken: LOTT was not designed to assess individual responses to oxygen treatment; individual responses to oxygen treatment can vary. Each COPD patient should discuss their own personal situation with their healthcare provider. Doctors should also continue to emphasize the importance of not smoking.
Additional Information: For more information about LOTT, please see the complete study published in the New England Journal of Medicine: http://www.nejm.org/doi/full/10.1056/NEJMoa1604344. LOTT is just one study among many supported by NHLBI on how to best treat COPD. NHLBI will continue to support investigators to search for other ways to improve survival and avoid hospital admissions in people with COPD with moderately low blood oxygen levels.
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Q10: Where are the results of this study published?