human lung anatomy
RESEARCH FEATURE

Long-Term Oxygen Treatment Trial (LOTT) Frequently Asked Questions

OVERVIEW


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. 

For the Media:  NHLBI Engagement and Media Relations Branch, nhlbi_news@nhlbi.nih.gov 301-496-4236 Ask for press officer on duty

Q1: Why was the LOTT Study conducted?

  • Past research has shown that long-term oxygen treatment improves survival in those with chronic obstructive pulmonary disease (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.  The LOTT study was designed to answer this question. Oxygen treatment 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.
  • To assess the possible benefits to this population, the National Heart, Lung, and Blood Institute (NHLBI) and the Centers for Medicare & Medicaid Services (CMS) conducted a randomized clinical trial called the Long-Term Oxygen Treatment Trial (LOTT). 

Q2: What did LOTT results show?

  • The study showed that oxygen treatment is not beneficial for the group with moderately low levels of blood oxygen. It neither had an effect on time to death or first hospitalization nor rates of hospitalizations.
  • 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.
  • These are important findings.  Past research had shown that oxygen treatment improves survival in those with COPD and severely low levels of blood oxygen. 
  • The LOTT study is just one study in a diverse research program supported by NHLBI aimed at identifying treatments to improve survival and avoid hospitalizations in COPD patients with moderately low levels of blood oxygen.

Q3: How does this study define moderately low levels of blood oxygen and severely low levels of blood oxygen? How are blood oxygen levels measured?

  • In the LOTT study, patients with moderately low levels of blood oxygen are defined as those with a blood oxygen saturation (peripheral capillary oxygen saturation, or SpO2) between 89 and 93 percent at rest (moderate resting hypoxemia), or a SpO2 below 90 percent during an exercise test, the 6-minute walk test.
  • Patients with severely low levels of blood oxygen are defined as those with a SpO2 equal to or less than 88 percent at rest. This later 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.

Q4: Who do these results apply to?  

  • The study evaluated COPD patients with moderately low levels of blood oxygen.
  • It is important to note that LOTT was not designed to assess individual responses to oxygen.
  • Patients with any form of COPD should discuss their own personal situation with their healthcare provider.

Q5: What should doctors tell their COPD patients in light of the LOTT results? 

  • 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.
  • Currently, no cure for COPD exists, but there are a number of treatment options, including the use of bronchodilators and steroids, as well as pulmonary rehabilitation, surgery, and lung transplantation.  Maintenance of general preventative measures is also important, like flu shots and pneumococcal vaccine.
  • Researchers worldwide are continuing to study new drugs or repurpose old ones to improve treatments. They are also working on better ways to detect COPD early to test if an early application of the currently available drugs can slow the course of the disease.

Q6: Will Medicare still cover oxygen for beneficiaries with moderate COPD?

  • Although the LOTT study demonstrated that most people with chronic obstructive pulmonary disease (COPD) and moderately low levels of blood oxygen do not benefit from supplemental home oxygen, Medicare current coverage policy for home oxygen therapy is flexible enough to cover patients with moderate COPD who may have hypoxia-related symptoms or findings that might be expected to improve with oxygen therapy, if providers and patients make that decision. 

Q7: How much does Medicare spend on oxygen therapy for COPD each year?  Do figures break down for treatment of moderate vs. severe COPD?

  • According to the Medicare Chronic Condition Warehouse analysis of 2014, Medicare spends approximately $26,500 per capita, per year.  This was not broken down by severity of COPD.

Q8: What other research is NHLBI supporting to better prevent and treat COPD?

  • NHLBI supports a vast portfolio of research in COPD, ranging from basic science to clinical trials.
  • NHLBI recognizes the wide heterogeneity, and potentially different treatments needed, among people with COPD.  For example, the Institute supports two large cohort studies, called SPIROMICS and COPDGene, aiming at characterizing COPD patients biochemically, genetically, and through the use of imaging techniques. This research may lead one day to precise treatments for specific groups of COPD patients, and has already led to the identification of a distinct patient population currently being studied in a clinical trial conducted by the NHLBI-funded Pulmonary Trials Cooperative (PTC). Another example is represented by research targeting the development of gene therapy for alpha-1 antitrypsin deficiency, a genetic condition that frequently leads to COPD.
  • Also, NHLBI recently convened the first-ever COPD National Town Hall with the express purpose of developing a national action plan for addressing this disease.

Q9: What is a good source for additional information on COPD?

Q10: Where are the results of this study published? 

Related Health Topics

What Is COPD?