Supplemental oxygen is often prescribed at hospital discharge after an exacerbation of chronic obstructive pulmonary disease (COPD), but decision making about this therapy could use some improvement, according to Laura Feemster, MD, MS.
Use of short-term oxygen after an acute exacerbation has no direct support in the literature and is based on trials of long-term oxygen therapy for chronic hypoxemia, said Dr. Feemster, who is an associate professor in the division of pulmonary, critical care, and sleep medicine at the VA Puget Sound and University of Washington in Seattle.
In a talk at the American Thoracic Society (ATS)'s 2020 conference, held virtually in August, she reviewed the evidence on and some of the barriers to appropriate use of oxygen therapy in COPD patients at hospital discharge and at home.
Use of supplemental oxygen for chronic severe resting hypoxemia is based mainly on two randomized controlled trials published in the early 1980s, Dr. Feemster said. In a study by the Medical Research Council Working Party, which was published in the March 28, 1981, Lancet, 87 patients were randomly assigned to at least 15 hours per day of oxygen versus no oxygen. To qualify for the study, patients had to have a PaO2 of 40 to 60 mm Hg, an age younger than 70 years, a history of chronic bronchitis or emphysema, and fixed airflow obstruction. The study found a 59% reduction in the relative risk of death at five years among patients who received the 15 hours of oxygen per day versus none, Dr. Feemster said.
The Nocturnal Oxygen Therapy Trial, meanwhile, was published in the Sept. 1, 1980, Annals of Internal Medicine and included patients who were ages 35 years or older and had a postbronchodilator FEV1/FVC of less than 0.7 and a PaO2 less than or equal to 55 mm Hg or less than or equal to 59 mm Hg with cor pulmonale or polycythemia. They were randomly assigned to receive nighttime oxygen only, which averaged about 12 hours a day, or 24 hours of oxygen a day, which averaged about 18 hours of use. A 48% reduction was seen in the relative risk of death among patients assigned continuous oxygen versus nighttime alone.
“Taken together, these two studies demonstrate strong evidence that there's a dose-response benefit in survival for patients with chronic resting hypoxemia who are prescribed continuous oxygen,” Dr. Feemster said. After those initial trials, she noted, the use of oxygen became more widespread and the evidence was extrapolated to patients with characteristics other than those studied, including exercise desaturation and for short-term use after an exacerbation.
“It was not until the Long-Term Oxygen Treatment Trial was published in 2016 …that we had another large randomized trial that really examined this question [of benefit of oxygen for exercise desaturation],” Dr. Feemster said. In that trial, which appeared in the Oct. 1, 2016, New England Journal of Medicine, 738 patients at 42 sites with moderate resting hypoxemia and isolated ambulatory desaturation were randomly assigned to receive either supplemental oxygen or no supplemental oxygen and followed for a median of 18.4 months. No difference was seen between the groups in time to death or time to first hospitalization, or in secondary outcomes.
“So unfortunately, when it comes to the patients … that are prescribed oxygen at hospital discharge after an acute exacerbation of COPD, there really is no good evidence [to guide us],” Dr. Feemster said. “What we do know is that among patients who are sent home on oxygen after an exacerbation that many of them, 30% to 50%, will no longer meet criteria two to three months after the recovery from their exacerbation.”
Dr. Feemster referred to an article published in the Dec. 1, 2019, Respiratory Care that outlined steps to ensure that patients receive appropriate oxygen therapy from hospital to home. Physicians should first make sure that patients are appropriately evaluated for oxygen need, that this need is appropriately documented, and that the oxygen is appropriately prescribed, she said.
“There's also an important step where patients need to be educated on the use of oxygen prior to their discharge. In addition, it is important to make sure that when they transition home that they receive the appropriate oxygen equipment and are well versed in its use,” Dr. Feemster said.
Breakdowns at these transition points can lead to poor outcomes and sometimes readmission, Dr. Feemster said. A study published in the Sept. 20, 2017, Chronic Obstructive Pulmonary Diseases found that of 335 patients at two centers hospitalized with a COPD diagnosis, only about a quarter received appropriate evaluation for a supplemental oxygen requirement within 48 hours before hospital discharge, regardless of whether they were on oxygen before admission. Rates were even lower among patients with a COPD diagnosis who were hospitalized for another reason. “This demonstrates that the majority of patients who are in the hospital with a diagnosis of COPD are not being evaluated for the appropriate dose of oxygen,” Dr. Feemster said.
In another study published in the March 1, 2019, Respiratory Care, a medical center in Australia examined its existing standard clinical pathway used for assessment and management of patients referred for short-term oxygen therapy after discharge. The pathway involved a standardized prescription, routine follow-up at an oxygen therapy clinic four weeks after discharge, patient education by a nurse educator, and oxygen delivery to the discharge destination by the oxygen service provider. “So it seems like this clinical pathway was really hitting a number of the points that we had identified as being omitted in the steps of appropriately discharging patients home with oxygen,” Dr. Feemster said.
Of 137 patients in the study who were prescribed continuous oxygen for a nonpalliative indication, only 70% had what was deemed appropriate assessment and actually qualified for continuous oxygen at discharge. Thirteen percent were assessed and did not have resting hypoxemia but received a prescription for continuous oxygen anyway, and 17% were not appropriately assessed but were given oxygen, “highlighting the need to really make sure that we're appropriately identifying, evaluating, and documenting need of oxygen for these patients,” Dr. Feemster said.
An ATS workshop report on optimizing home oxygen therapy published in the December 2018 Annals of the American Thoracic Society reported that gaps in clinician education can contribute to inappropriate prescriptions. Barriers that affect clinician knowledge include lack of a standardized system for assessment and reassessment of oxygen need, Dr. Feemster noted. “It's also a difficult and time-consuming process for clinicians to access, compare, and evaluate the available oxygen delivery devices, which can be a real problem for clinicians who aren't used to necessarily working with oxygen on a daily basis,” she said. “There's also a lack of clarity on the part of the clinician as to the role that CMS and competitive bidding can play when fewer restricted portable systems are available for patients.” (See related article for more on types of portable home oxygen.)
Patient education can also be problematic, Dr. Feemster said. She pointed to an article published in the January 2018 Annals of the American Thoracic Society looking at patient perceptions of the adequacy of supplemental oxygen therapy. Among 1,926 respondents, 39% had COPD, and about a third had had a hospital admission or ED visit in the past 12 months. “The majority of patients, 64%, reported that their oxygen education was received [from] the people who dropped off their oxygen at their house rather than from health care personnel,” Dr. Feemster said. Eight percent did report receiving oxygen education from health care personnel, but 10% reported receiving no education at all.
“You can see that this has real impact for the patients, as we would expect,” Dr. Feemster said. Forty-three percent of patients who received oxygen education from health care personnel reported oxygen issues, versus 64% of those who received no education. The findings highlight the need to educate patients about the use of their equipment, she noted.
Reassessment of home oxygen needs is also key, Dr. Feemster said. She reminded her audience that a substantial percentage of patients prescribed home oxygen at hospital discharge no longer meet the criteria two to three months later and that 35% to 65% of patients who are prescribed home oxygen often do not have their needs appropriately reassessed after discharge and continue on oxygen indefinitely.
“Make sure that patients are identified who have been prescribed short-term oxygen use, that they are appropriately reevaluated, and when that reevaluation happens, that's acted on appropriately with revised documentation, prescriptions, and then additional patient education,” she said. In 2014, the American Thoracic Society published a Choosing Wisely recommendation stating that short-term oxygen should not be continued without assessing the patient for ongoing hypoxemia.
“We spend a lot of money on oxygen in this country. Approximately a million Medicare beneficiaries are prescribed home oxygen, resulting in $2 billion annually spent on oxygen. For some of these patients who have been sent home on oxygen after a hospitalization and continued indefinitely, that is excess cost that we need to think about,” Dr. Feemster said.
Even more important, she said, are the potential harms to patients. Twenty percent to 40% of patients using supplemental oxygen continue to smoke, which can lead to fires, burns, and sometimes fatalities. Patients who use oxygen are at risk for falls due to entanglement in tubing and for social isolation if oxygen makes it more difficult for them to leave their homes, she said, leading to reductions in quality of life. “Taken together, these harms become even more important among patients who are prescribed oxygen without an evidence-based need for its use,” she said.
Optimization of supplemental oxygen from hospital to home in patients with COPD will require overcoming barriers at each step, Dr. Feemster concluded. “The things that are needed are systematic identification and evaluation of patients benefiting from oxygen prior to discharge, patient and clinician education on appropriate prescription devices and patient education on the possible short-term need for oxygen to help prepare them for possible discontinuation, and a rigorous system to ensure that there's appropriate follow-up reevaluation and discontinuation when needed,” she said.