Home Oxygen Therapy for Patients With COPD: Time for a Reboot

Home Oxygen Therapy for Severe Resting Room Air Hypoxemia

The Medical Research Council (MRC) multi-center clinical trial randomized 87 people with COPD to LTOT via nasal cannula for at least 15 h/d with a target P_aO2 of 60 mm Hg or higher versus no home oxygen.¹² To be eligible, subjects needed to be < 70 years old, have chronic bronchitis or emphysema with “irreversible airway obstruction” (defined as FEV₁ < 1.2 L), and resting room air P_aO2 of 40–60 mm Hg. Subjects with evidence of cor pulmonale were hospitalized and needed to demonstrate stable arterial blood gas, FEV₁, and weight over a period of at least 3 weeks to be eligible.

Once enrolled, all study subjects were urged to stop smoking and had close follow-ups that included an out-patient clinic visit every 2 months. Subjects in the home oxygen group received oxygen through various types of equipment, including a stationary oxygen concentrator, reservoir of liquid oxygen, or compressed gas tanks. Participants in the home oxygen group also received periodic home visits (frequency not specified) to assess oxygen usage and collect arterial blood gases; this information was used to promote appropriate use of home oxygen among the subjects in the intervention group. At 5 years, 19 of 42 subjects (42%) in the home oxygen therapy group had died, compared to 30 of 45 patients (66%) in the usual care (no home oxygen) group. The 5-year relative risk of death was 0.41 (95% CI 0.17–0.98) favoring the home oxygen group compared to the no home oxygen group. When interpreting these results, it is important to remember that home visits to carefully titrate the oxygen prescription and equipment to individual needs likely contributed to the survival benefits observed in the intervention group.

The multi-center Nocturnal Oxygen Therapy Trial (NOTT) sought to determine whether LTOT prescribed 24 h/d offered benefits beyond that observed when LTOT is prescribed for nighttime use only.¹³ In the NOTT study, 203 subjects with COPD were randomized to continuous LTOT (ie, 24 h/d) or nocturnal LTOT. To be eligible, individuals needed to be at least 35 years old, have COPD confirmed with post-bronchodilator FEV₁/FVC < 0.70, and have severe resting room air hypoxemia (P_aO2 ≤ 55 mm Hg or P_aO2 56–59 mm Hg with evidence of erythrocytosis or cor pulmonale). The study protocol required confirmation of severe hypoxemia twice, assessed at least 1 week apart over a 3-week COPD exacerbation-free period. Patients were excluded if they had clinically important comorbid conditions expected to affect morbidity or mortality or if there were concerns about nonadherence to therapy.

In the NOTT study, LTOT was delivered by nasal cannula at 1–4 L/min with a target P_aO2 of 60–80 mm Hg for all subjects. The oxygen prescription in the continuous LTOT group was increased by 1 L/min during exercise and sleep. As with the MRC study, the oxygen equipment for study participants included stationary oxygen concentrators, liquid oxygen systems, and compressed oxygen tanks. Importantly, the stationary concentrators and oxygen reservoirs were outfitted with timers that recorded the duration of gas flow. This information was used to estimate adherence to LTOT, although this method underestimated total oxygen use if patients also used portable equipment for liquid oxygen or small tanks of compressed gas.

Subjects in both groups in the NOTT study appeared to have even more intensive support than those in the LTOT group in the MRC study. All NOTT subjects were assessed during home visits by a nurse practitioner once per week and were asked to attend out-patient clinic appointments once per month for 6 months; then, NOTT participants received home visits once per month and were asked to attend clinic visits every 3 months for the duration of the study.

Data from oxygen timers on stationary equipment suggested that oxygen was used for about 18 h/d in the continuous LTOT group and for about 12 h/d in the nocturnal LTOT group. The NOTT subjects were followed for a mean of 19.3 months. At 12 and 24 months, mortality in the continuous LTOT group was lower than in the nocturnal LTOT group (11.9% vs 20.6% and 22.4% vs 40.8%, respectively). Overall mortality significantly favored the continuous LTOT group compared to the nocturnal LTOT group (relative risk 0.52, 95% CI 0.31–0.85). Whether these benefits would be observed in the absence of intensive home and out-patient clinic supports is unknown. For example, it is possible that, without such support, subjects in both groups would not know how to use the LTOT equipment properly, which would lead to no observed difference in outcomes between groups. Such support is often not available to patients prescribed LTOT today.

Home Oxygen Therapy for Moderate Resting Room Air Hypoxemia

The survival benefits of LTOT do not appear to accrue to individuals with COPD who have less than severe resting hypoxemia. In the Long-term Oxygen Therapy Trial (LOTT), 738 subjects with COPD and moderate resting hypoxemia (S_pO2 89–93%), exercise-induced hypoxemia during a 6-min walk test (S_pO2 < 90% for at least 10 s and S_pO2 at least 80% for at least 5 min), or both were randomized to LTOT or no oxygen.¹⁴ LTOT was prescribed 24 h/d using stationary and portable oxygen equipment in subjects who had moderate resting hypoxemia, but with exercise and during sleep in subjects who only had exercise-induced hypoxemia. In the former group, LTOT was prescribed at 2 L/min via nasal cannula. In the latter group, the oxygen prescription was individualized (2 L/min or higher to maintain S_pO2 at least 90% while walking for at least 2 min) and reassessed annually. As with the MRC and NOTT studies, the assignment of oxygen was not masked to subjects or study staff.

Among all 738 subjects, there were no discernable differences in time to death or first hospitalization (primary outcome; hazard ratio 0.94, 95% CI 0.79–1.12, P = .52) over 6 years in both study groups. Similar findings were noted for the primary outcome in the 133 subjects who had moderate resting hypoxemia only (prescribed LTOT vs no oxygen: hazard ratio 0.96, 95% CI 0.63–1.47) and in the 286 subjects with both moderate resting hypoxemia and exertional desaturation (hazard ratio 0.95, 95% 0.72–1.27). In addition, the study did not find consistent benefits with home oxygen therapy in any of the numerous secondary outcomes among all subjects (eg, components of the primary outcome, quality of life, lung function, distance walked in 6 min). Taken together, these 3 studies (NOTT, MRC, and LOTT) provide strong evidence that home oxygen prescribed for at least 15 h/d saves lives for patients with COPD and severe, but not for patients with moderate resting hypoxemia.¹⁵

Ambulatory Oxygen Therapy for Exertional Desaturation

Ambulatory oxygen therapy refers to oxygen delivered during exercise or other activities of daily living. The LOTT study adds to the existing literature about the benefits of ambulatory oxygen therapy. Prior to LOTT, there were 4 randomized clinical trials of ambulatory oxygen therapy in total of 237 subjects (26–143 participants subjects per study) with COPD and exertional dyspnea or desaturation without evidence of severe resting hypoxemia.^16–19 All 4 studies compared portable oxygen or identical appearing compressed air over a 2–12-week period; subjects and study staff were masked to treatment assignment. A meta-analysis of these studies suggests the potential to improve dyspnea and fatigue with exertion.²⁰ The LOTT study results indicated no significant difference among the those prescribed LTOT versus no oxygen for the primary outcome (death or first hospitalization) in the 286 subjects who had exertional desaturation with moderate resting hypoxemia (results presented above) and in the 319 subjects with exertional desaturation without moderate hypoxemia (hazard ratio 0.95, 95% CI 0.73–1.24).¹⁴ These 5 randomized clinical trials involving a total of nearly 850 people with COPD suggest the need for a more nuanced approach to treating exertional desaturation in the absence of severe resting hypoxemia. Such individuals may benefit from a discussion with their health care provider to understand their preferences and values for the treatment of dyspnea and fatigue (ie, shared decision making),²¹ rather than routinely prescribing ambulatory oxygen therapy in this population.

Short-Term Oxygen Therapy

Short-term oxygen therapy refers to initiating oxygen during a period of severe hypoxemia that is likely to be temporary (eg, during a COPD exacerbation). Studies in subjects who are prescribed home oxygen during a respiratory exacerbation (most of whom have COPD or are hospitalized for a COPD exacerbation) suggest that 30–50% of such individuals no longer have severe resting hypoxemia within 3 months.^22,23 Guidelines therefore recommend re-assessing home oxygen requirements after hospital discharge to modify the oxygen prescription (eg, reductions or increases in oxygen flow, prescribing portable equipment) or to discontinue it altogether in patients who no longer have a clinical indication.^15,24 Dedicated oxygen clinics that re-assess a patient's need for continuing home oxygen after hospital discharge and provide patient education can help implement these guideline recommendations.²² However, dedicated home oxygen clinics are not routine in most health systems; findings from a multi-center qualitative study suggest that patients who are prescribed home oxygen are not routinely re-assessed for their home oxygen need, which may lead some to use home oxygen even when they do not need it.²⁵

Patients and Caregivers

Mr Carter's experience after being started on home oxygen therapy is not unique. In February 2017, people with COPD and their families attended a health education workshop about home oxygen in Florida, convened by the Villages Airheads (a patient support group), the COPD Foundation (a non-profit organization that supports education, research, and policies to support the needs of people with COPD),³⁹ clinicians, and researchers from the SHERLOCK Consortium.

Workshop participants expressed a high level of frustration about gaps in care and information about home oxygen therapy. Participants had numerous questions about practical aspects of living with home oxygen, including how long they would need to use oxygen, performance characteristics (eg, size, weight, noise level, battery life, adequacy of oxygen flow) of various types of stationary and portable oxygen concentrators, quality of services provided by different DME providers, out-of-pocket costs of various types of equipment and disposables (eg, nasal cannula, humidifiers), options during air travel, safety of using home oxygen during a shower, how to troubleshoot when their oxygen equipment malfunctions, and assessing the adequacy of their home oxygen prescription with changes in respiratory symptoms.

Clinicians felt that they were mostly unprepared to answer the questions with the level of detail that workshop participants wanted, so we asked participants to submit their questions in writing and, with the help of the AARC and the COPD Foundation, produced a Frequently Asked Questions and Answers document that was made available after the workshop (Table 2).⁴⁰ Participants identified an ongoing need for an independent and trustworthy source of updated information to supplement what they were able to learn from their physician offices, DME providers, and other content that may be available online—similar to what is available through Consumer Reports for other products and services.⁴¹ Participants also supported the development of a national oxygen equipment registry to facilitate public reporting about access, out-of-pocket costs, and performance characteristics of different oxygen equipment by region and by insurance provider.⁴²

DME Providers

The role of respiratory therapists in home oxygen services has been diminished dramatically over the past 3 decades. Until the early 2000s, DME providers were competing to provide more services to support patients on home oxygen, including home visits, during which respiratory therapists would provide self-management education and training to patients and their caregivers.

This support to end-users (patients, their families, and other caregivers) was especially important to those who were newly prescribed home oxygen, a group who needed practical information about their equipment (such as Mr Carter, who did not know how to remove the regulator from a used oxygen cylinder) and options for other types of equipment (eg, portable concentrators, oxygen-conserving devices) that may be better tailored to their current needs.

Reimbursements for home oxygen services have been declining since the 1990s, but they were reduced even more sharply following the implementation of the competitive bidding process by the Centers for Medicare and Medicaid Services in 2009 (initially in selected metropolitan areas, but then nationwide in 2016).^35,43 Under this competitive bidding process, DME providers have seen a dramatic reduction in reimbursement for home oxygen services (ie, 50% or more). Such reductions in reimbursements have eliminated the ability of nearly all DME providers to routinely include home visits by respiratory therapists when delivering home oxygen. In most cases, a technician without clinical training now delivers home oxygen equipment to patients. By law, these technicians are not permitted to address any clinical questions from patients or their caregivers, including requests to assess the adequacy of home oxygen equipment or the ability of a patient or their caregivers to use the equipment appropriately.

The majority of orders for home oxygen are written as the patient is being discharged to home following an acute cardiopulmonary illness, rather than in the out-patient setting.^22,44 DME companies are often selected by hospital case managers or discharge planners based on speed of response, which implies a focus on the transaction, not the transition of care. The goal is to make sure the DME provider's truck gets to the patient's home before the oxygen cylinders provided on discharge from the hospital run out. There is a residual belief by clinicians that the DME provider is still a safety net that can provide all the education that is often not feasible to provide in the hospital. This is no longer true. As a respiratory therapist who previously worked in the DME industry explained, “There is now a giant hole in the safety net.”

Front-Line Hospital-Based and Out-Patient Clinicians

Hospital-based clinicians noted varying levels of awareness and ability to provide home oxygen education to patients. Hospital-based physicians report being unable to answer questions about equipment, service, payment, or duration of home oxygen therapy that is initiated in the hospital. Hospital-based nurses are often responsible for reviewing discharge instructions and education materials with patients. However, the discharge process is typically short (5–10 min) and covers the patient's entire care plan. Details about home oxygen therapy are generally limited to what is documented by physicians. Moreover, patients are often overwhelmed with the amount of information provided at hospital discharge and are rarely in a position to ask questions about their home oxygen equipment (which they will often see only once they get home). Hospital-based respiratory therapists are not often involved in patient education or discharge unless requested. Even then, respiratory therapists acknowledged that they were generally not familiar with oxygen equipment supplied by DME providers and delivered to patients' homes.⁴⁵ Most hospital-based clinicians we interviewed believed that their patients were getting sufficient education and support for home oxygen equipment from the DME providers, apparently unaware of how significantly these services have been reduced in recent years.

Out-patient clinicians recognized that their patients were in need of more education and support but noted that they were also poorly equipped to provide it. Out-patient nurses reported that a substantial proportion of patients do not attend their follow-up appointments and may not undergo a re-evaluation regarding their home oxygen requirements. Nurses are also often unfamiliar with oxygen equipment and services that a patient may receive from a DME provider, and therefore they refer patients to their DME provider for any equipment-specific questions. An out-patient advanced practice nurse also expressed her frustration with the lack of information she could access from the patient's hospitalization: I only have 20 min with returning patients. It's not a lot of time for the clinical evaluation and patient and caregiver education. I don't think they're doing a walk test in the hospital. I don't know what oxygen company they were set up with. The discharge notes and summary are insufficient, as there is nothing documented related to the home oxygen prescription. There's no communication with the out-patient provider.

Resume the LTOT Consensus Conference Series With a Full Complement of Stakeholders

The chain of home oxygen care involves multiple stakeholders in health care and community settings. Stakeholders include people prescribed home oxygen and the people who care for them; home-based professionals, including DME providers and home health agencies; hospital-based and out-patient clinicians (eg, physicians, nurse practitioners, respiratory therapists, physical therapists); home oxygen product manufacturers; payers (public and private); and policy makers. Building on the work of Dr Petty, convening an annual LTOT consensus conference would provide a mechanism to support stakeholder-supported standards, educational programs, and research to inform policies.

Leverage the Framework Proposed by the U.S. COPD National Action Plan

The COPD Action Plan is intended to reduce the public health burden of COPD by: (1) empowering people with COPD, their families, and other caregivers; (2) promoting the prevention of COPD and management of COPD across the care continuum; (3) supporting the collection of COPD-related public health data that drive change and track progress; (4) increasing and sustaining research to improve the care and health of people with COPD; and (5) translating the policies, educations, and other programs into research and public health care actions.³⁷ This framework of goals could support a range of efforts to promote the appropriate use of LTOT in patients with COPD, including the development of a trustworthy resource about home oxygen equipment and services for patients and caregivers, the improvement of hospital-to-home transitions for patients prescribed home oxygen therapy, the design and implementation of a national oxygen registry to identify opportunities for quality improvement initiatives, and the conduct of stakeholder-supported hybrid effectiveness/implementation studies to fill care gaps.