Home Use of Oxygen and Home Oxygen Use to Treat Cluster Headaches

The Centers for Medicare & Medicaid Services (CMS) is proposing changes to two separate, but medically related, National Coverage Determinations (NCDs). Given new information in the peer-reviewed medical literature, we are removing the NCD for Home Oxygen Use to Treat Cluster Headache (CH) (240.2.2). We are also revising the NCD for Home Use of Oxygen (240.2) based on our removing of the NCD for Home Oxygen Use to Treat CH. We summarize these changes below and fully explain our rationale in the Analysis section of this NCD decision memo.

CMS proposes to remove its NCD at section 240.2.2 of the Medicare NCD Manual, ending coverage with evidence development, and allow the Medicare Administrative Contractors (MACs) to make coverage determinations regarding the use of home oxygen and oxygen equipment for CH.

CMS also proposes to modify its NCD for Home Use of Oxygen at section 240.2 of the Medicare NCD Manual to expand patient access to oxygen and oxygen equipment in the home, and to permit contractors to cover the use of home oxygen and oxygen equipment in order to treat CH and other acute conditions.

The scope of this decision does not include any consideration of Home Use of Oxygen in Approved Clinical Trials, identified in section 240.2.1 of the NCD manual. Additionally, the scope of the decision does not include any consideration of hyperbaric oxygen for any indication, currently identified in section 20.29 of the NCD manual.

See Appendices B and C for proposed NCD Manual language.

CMS is seeking comments on our proposed decisions consistent with the public process established by §1862(l) of the Social Security Act.  We will respond to public comments in a final decision memorandum.

TO: 		Administrative File: CAG-00296R2

FROM: 		Tamara Syrek Jensen, JD
			Director, Coverage and Analysis Group

			Joseph Chin, MD, 
			Deputy Director, Coverage and Analysis Group

			JoAnna Baldwin, MS
			Acting Director, Division of Policy and Evidence Review
		
			Melissa Evans, PhD, MSAE 
			Deputy Director, Division of Policy and Evidence Review

			Susan Miller, MD
			Lead Medical Officer
		
			Heather Hostetler, JD  
			Lead Analyst
		
SUBJECT: 	Proposed Decision to Remove National Coverage Determination for Home Oxygen Use to Treat Cluster Headache (NCD 240.2.2) 
and to Modify National Coverage Determination for Home Use of Oxygen (NCD 240.2)

DATE: 		July 2, 2021

I. Proposed Decision

The Centers for Medicare & Medicaid Services (CMS) is proposing changes to two separate, but medically related, National Coverage Determinations (NCDs). Given new information in the peer-reviewed medical literature, we are removing the NCD for Home Oxygen Use to Treat Cluster Headache (CH) (240.2.2). We are also revising the NCD for Home Use of Oxygen (240.2) based on our removing of the NCD for Home Oxygen Use to Treat CH. We summarize these changes below and fully explain our rationale in the Analysis section of this NCD decision memo.

CMS proposes to remove its NCD at section 240.2.2 of the Medicare NCD Manual, ending coverage with evidence development, and allow the Medicare Administrative Contractors (MACs) to make coverage determinations regarding the use of home oxygen and oxygen equipment for CH.

CMS also proposes to modify its NCD for Home Use of Oxygen at section 240.2 of the Medicare NCD Manual to expand patient access to oxygen and oxygen equipment in the home, and to permit contractors to cover the use of home oxygen and oxygen equipment in order to treat CH and other acute conditions.

The scope of this decision does not include any consideration of Home Use of Oxygen in Approved Clinical Trials, identified in section 240.2.1 of the NCD manual. Additionally, the scope of the decision does not include any consideration of hyperbaric oxygen for any indication, currently identified in section 20.29 of the NCD manual.

See Appendices B and C for proposed NCD Manual language.

CMS is seeking comments on our proposed decisions consistent with the public process established by §1862(l) of the Social Security Act.  We will respond to public comments in a final decision memorandum.

II. Background

Throughout this document we use acronyms, some of which are not defined as they are presented in direct quotations. Please find below a list of these acronyms and corresponding full terminology:

CH - cluster headache
CCH – chronic cluster headache
CMS - Centers for Medicare & Medicaid Services
CMN – Certificate of Medical Necessity
DME – Durable medical equipment
ECH – episodic cluster headache
MAC – Medicare Administrative Contractor
NBOT - normobaric oxygen therapy
NCA - National Coverage Analysis
NCD - National Coverage Determination
US - United States

Introduction

CHs are headaches grouped under the category of trigeminal autonomic cephalalgias. CHs are manifested by attacks of severe unilateral pain. This pain, which at times is so excruciating that these headaches are known as ‘suicide headaches’, is located either singularly or in combination in the orbital, supraorbital, or temporal areas of the face. CHs commonly last for 15–180 minutes and usually occur from once every other day to eight times a day. The pain is associated with ipsilateral conjunctival injection, lacrimation, nasal congestion, rhinorrhoea, forehead and facial sweating, miosis, ptosis and/or eyelid edema, and/or with restlessness or agitation. Age at onset for CHs is usually 20–40 years. Men experience CHs three times more often than women (May, 2005; May, 2020; Headache Classification Committee of the International Headache Society, 2018).

The lifetime prevalence of CH for adults of all ages is approximately 0.1 percent. Though some patients have a single bout of this disorder, CHs also exhibit two different types of continuing patterns.  The episodic form of CH is the most common, affecting 80 to 90 percent of patients.  It is characterized by periods of attacks (clusters or bouts) and periods of remission.  On average, a cluster period lasts 2 to 12 weeks while remissions can last up to 12 months or longer.  When not in a bout, patients are usually asymptomatic.  In the chronic form of the disorder, attacks occur without significant periods of remission. The chronic form of CH is diagnosed after a year without remission, or if a remission has lasted less than three months. Chronic CHs may present primarily or evolve from the episodic type. (May, 2005; May, 2020; Headache Classification Committee of the International Headache Society, 2018).

The treatment of CH can be divided into that which is acute (used to abort the exquisitely painful headache at the time it occurs) or preventative (May, 2020). Though medications may be helpful to some individuals, since 1952, oxygen has been used to treat the acute attacks of CHs (Geerlings, Haane & Koehler, 2011).  Home oxygen therapy provides air that contains more oxygen than normal to a patient through a mask or tube connected to a device in a patient’s home.  Home oxygen therapy is used to treat a variety of conditions.  In 2011, CMS issued a NCD for Home Oxygen Use to Treat CH 240.2.2). At that time, CMS concluded that the evidence did not demonstrate that the home use of oxygen to treat CH improved health outcomes in Medicare beneficiaries, though the Agency was supportive of further research on the topic.

The primary goal of this National Coverage Analysis (NCA) is to examine the evidence developed in the last decade regarding the response to oxygen therapy of those individuals who attempt to acutely abort their CH with this medical gas.  Importantly though, ending CED for coverage of home oxygen for the treatment of CH, will also necessitate a review of 240.2 NCD for Home Use of Oxygen to determine if this policy impedes patient access to oxygen therapy in the home for the treatment of acute conditions, be they CHs or other illnesses (e.g. COVID-19).  This NCD, effective since October 27, 1993 arguably provides for home oxygen therapy only if the patient is in the ‘chronic stable state.’ We note that since the inception of the Public Health Emergency (PHE) due to the COVID 19 pandemic, CMS has begun to permit health care services to increase the capacity of the American health care system outside the setting of the traditional inpatient hospital, including the treatment of acute illnesses. (CMS Press Release, November 25, 2020).  The ability to provide home oxygen has been crucial to treatment of patients during the pandemic.

In summary, CMS is opening this NCA to examine first, if coverage of oxygen in the home for CH, is reasonable and necessary under the Medicare program.  Secondly, if required, CMS will review the NCD for Home Use of Oxygen (240.2) to determine if this policy impedes patient access to oxygen therapy in the home for the treatment of CH or for any other acute condition.

III. History of Medicare Coverage

CMS has provided formal coverage of home oxygen since the 1980s.  In 1993, CMS issued NCD 240.2 providing Medicare coverage of home oxygen and oxygen equipment under the durable medical equipment (DME) benefit (see §1861(s)(6) of the Social Security Act) only for patients with significant hypoxemia who meet the medical documentation, laboratory evidence, and health conditions specified elsewhere in the NCD. The policy is codified in section 240.2 of the Medicare NCD Manual (Pub. 100-03).

In 2011, CMS issued a NCD for Home Oxygen Use to Treat CH (240.2.2).  At that time, CMS concluded that the evidence did not demonstrate that the home use of oxygen to treat CH improved health outcomes in Medicare beneficiaries. Therefore, the home use of oxygen to treat CH was not found to be reasonable and necessary under 1862(a)(1)(A) of the Act.  However CMS believed that the available evidence suggested that the home use of oxygen to treat CH was promising and supported further research under §1862(a)(1)(E) of the Social Security Act through the Coverage With Study participation (CSP) form of Coverage With Evidence Development (CED).  Therefore the NCD covered the home use of oxygen for CH for beneficiaries participating in an approved prospective clinical study comparing 100% normobaric oxygen therapy (NBOT) with at least one clinically appropriate comparator for the treatment of CH.  The policy is codified in section 240.2.2 of the Medicare NCD Manual (Pub. 100-03).

IV. Timeline of Recent Activities

V. Food and Drug Administration (FDA) Status

FDA regulates Oxygen, USP as a designated medical gas under sections 575-576 of the Federal Food, Drug, and Cosmetic Act. FDA regulates oxygen concentrators and certain equipment and delivery systems required for providing oxygen therapy as medical devices.

VI. General Methodologic Principles

When making NCDs, CMS generally evaluates relevant clinical evidence to determine whether or not the evidence is of sufficient quality to support a finding that an item or service falling within a benefit category is reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member.  The critical appraisal of the evidence enables us to determine to what degree we are confident that: 1) the specific assessment questions can be answered conclusively; and 2) the intervention will improve health outcomes for beneficiaries.  An improved health outcome is one of several considerations in determining whether an item or service is reasonable and necessary.

A detailed account of the methodological principles of study design that the agency utilizes to assess the relevant literature on a therapeutic or diagnostic item or service for specific conditions can be found in Appendix A.

VII. Evidence

Public Comment

Public comments sometimes cite the published clinical evidence and give CMS useful information.  Public comments that give information on unpublished evidence such as the results of individual practitioners or patients are less rigorous and therefore less useful for making a coverage determination.

CMS uses the initial public comments to inform its proposed decision.  CMS responds in detail to the public comments on a proposed decision when issuing the final decision memorandum.  All comments that were submitted without personal health information may be viewed in their entirety by using the following link https://www.cms.gov/medicare-coverage-database/details/nca-view-public-comments.aspx?NCAId=301&ExpandComments=n&type=Open&bc=AAgAAAAACAAA&.

Initial Comment Period: 8/17/2020 – 9/16/2020

During the initial 30-day public comment period CMS received 200 comments.  Of these 200 comments, 42 were not published on the CMS website due to excessive personal health information content; however, all comments were considered for this proposed decision.

We received 188 comments related to CH and all of the commenters supported coverage of the use of home oxygen to treat CH.  Most of the commenters supporting coverage of home oxygen for CH expressed that high-dose oxygen is a safe and effective non-pharmacologic treatment option for patients suffering from CH that is preferable to pharmacological treatments.  Most of the commenters also mentioned that home oxygen is a cost-effective treatment option for CH.

The majority of comments related to CH (131) were provided by commenters that did not specify their titles and/or organizations, but wrote of personal experience or family and friends who experience CH. There were 56 comments submitted by neurologists, other healthcare professionals and providers, as well as professional associations, societies and advocacy organizations, including the Alliance for Headache Disorders Advocacy, Cluster Busters, the American Headache Society, the Spinal SF Leak Foundation, and the American Cluster Headache Chronic Pain Association. An additional group comment was submitted by the Coalition for Headaches and Migraine Patients that included 257 co-signers.

There were 12 comments submitted related to the NCD for Home Use of Oxygen (NCD 240.2). All 12 commenters supported CMS reconsidering this NCD.  Several commenters recommended that CMS expand coverage for home oxygen to include both acute respiratory conditions and other non-respiratory illnesses that affect oxygen saturation levels, such as pneumonia patients, bronchitis, or any other acute condition, including exacerbation of chronic conditions. Several commenters requested various revisions to the medical documentation and laboratory evidence sections.  Recommendations included but are not limited to: remove the Certificate of Medical Necessity (CMN) requirement for home oxygen and instead use Standard Written Orders/Clinical Data Element Templates; minimize the requirement for patients to try other alternative treatments prior to being prescribed oxygen; remove the term “chronic stable state”; and change recertification and testing requirements.  Several commenters recommended changes to the covered blood gas group definitions and one commenter requested that CMS cover the services of respiratory therapists under home oxygen. 

Of the comments for NCD 240.2 Home Use of Oxygen, several were submitted by DME suppliers, providers and professional associations and societies, including the Council for Quality Respiratory Care, American Association for Homecare.  Additional group comments were submitted by American College of Chest Physicians with 11 co-signers that included Alpha-1 Foundation, American Association for Respiratory Care, American Lung Association, American Thoracic Society, COPD Foundation, Dorney Koppel Foundation, Pulmonary Fibrosis Foundation, Respiratory Compromise Institute. Respiratory Health Association and the US COPD Coalition.

VIII. CMS Analysis

NCDs are determinations by the Secretary with respect to whether or not a particular item or service is covered nationally by Medicare (§1869(f)(1)(B) of the Act).  In order to be covered by Medicare, an item or service must fall within one or more benefit categories contained within Part A or Part B, and must not be otherwise excluded from coverage. Moreover, with limited exceptions, the expenses incurred for items or services must be reasonable and necessary for the diagnosis or treatment of illness or injury or to improve the functioning of a malformed body member (§1862(a)(1)(A) of the Act).

Home Use of Oxygen Use to Treat Cluster Headaches (NCD 240.2.2)

The 2011 NCD for Home Oxygen Use to Treat CH (240.2.2), notes that the available evidence suggested the home use of oxygen to treat CH was promising and therefore supported further research under §1862(a)(1)(E) of the Social Security Act (the Act) through the CSP form of CED.  Consequently, Medicare would provide coverage of the home use of oxygen for beneficiaries with CH, only when participating in an approved prospective clinical study comparing normobaric 100% oxygen with at least one clinically appropriate comparator for the treatment of that condition.  To date, no research protocols studying the home use of oxygen for the treatment of CH have been submitted to CMS under NCD 240.2.2.  Based on conversations with stakeholders, we have been informed that clinical studies have been conducted and new evidence has been developed outside the context of CED as reviewed below. Stakeholders have informed us that patients with CH typically have unique characteristics to their disorder, comorbidities and concomitant treatments.  To that end, stakeholders, including the requester, have noted that the current CED clinical study requirements, while well intentioned, are challenging to implement for this treatment due to patient characteristics and care settings.  Based on stakeholder feedback, we do not anticipate that any CED protocols will be submitted for review in the near future due to the difficulty in enrolling an appropriately defined study population. 

For this reconsideration, we reviewed the current evidence for home use of oxygen to treat CH, which consisted of four published articles (one comparative trial, one SR and two guidelines).

The goal of research performed by Petersen et al. was to study possible differences in effect between three types of mask delivery systems of oxygen in the acute treatment of CH.  While doing so, they provided data comparing the use of DVO masks administering 100% oxygen versus air (21% oxygen and 79% nitrogen) to patients with CH.  No significant differences were noted in the provision of these different gases through DVO masks for the relief of the pain of CH at 15 and 30 minutes.  However, the small sample size (n = 10) precludes a definitive statement regarding the utility/non-utility of oxygen in the care of patients with this condition.

Bennett et al.(2015) conducted a SR to examine the efficacy and safety of NBOT in the acute treatment of CH.  Of the four studies noted, three had been previously considered in the 2011 NCD that determined the evidence did not demonstrate that the home use of oxygen to treat CH improved health outcomes in Medicare beneficiaries.  The one clinical trial published since 2011 mentioned in this systematic review studied only two individuals with CH, precluding our use of it to supply new information. Additionally, Bennett et al. (2015) highlighted that the early articles that concluded oxygen was useful for the treatment of CH, may have been based upon inappropriately sized sample populations, thereby casting doubt as to the strength of evidence associated with the use of oxygen therapy for the treatment of CH.  

In a similar vein, CPGs from the VA/DoD (2020) determined that there was insufficient evidence to recommend for or against oxygen therapy for the acute treatment of primary headaches, a classification that includes CH.  Taken as a whole then, the current evidence for the generalized use of oxygen for the treatment of CH reflects stakeholder comments about the small study sample sizes and difficulty enrolling well defined patients in clinical studies.

However, we recognize that the literature confirms there is benefit to the use of oxygen therapy for carefully selected individuals with CH.  For example, data obtained from the international Cluster Headache Questionnaire, with 1604 respondents from over 50 countries (with 80.5% reported from the United States, the United Kingdom, and Canada) demonstrated that 54% of respondents (582/1082), reported complete or very effective treatment of oxygen for their CH. Of the 139 respondents 65 years and older, oxygen was reported as completely effective or very effective in 56% (Pearson, Burish, Shapiro, Yan and Schor, 2019).  As noted in the CPGs of the VA/DoD (2020), the use of inhaled oxygen may be first line therapy for CH in selected patients and if successful, is then in itself “optimum therapy.”  Consequently, we believe that carefully chosen Medicare beneficiaries who suffer CH, will receive meaningful pain relief from oxygen therapy.  Therefore we propose to remove NCD 240.2.2, and allow the MACs to determine coverage for the use of home oxygen as a treatment option for CH, without the need for further clinical trials.  The MACs are structured to be able to take into account individualized patient factors, particularly when the overall prevalence of the disease is small, as it is in this patient population.

Home Use of Oxygen (NCD 240.2)

Because we are proposing to remove NCD 240.2.2, we are also proposing to modify the 1993 NCD 240.2, Home Use of Oxygen, in order to allow appropriate patient access to oxygen and oxygen equipment in the home when its use is reasonable and necessary to treat certain Medicare beneficiaries with CH.  In doing so, we believe these modifications will also address lessons learned during the COVID-19 public health emergency.  Since the inception of the Public Health Emergency (PHE) due to the COVID-19 pandemic, CMS has permitted waivers for health care services to increase the capacity of the American health care system outside the setting of the traditional inpatient hospital.  (CMS Press Release, November 25, 2020).  Many patients with COVID-19 developed low oxygenation and needed oxygen as part of their treatment outside the usual treatment settings.  The ability to provide home oxygen was crucial for many patients.  Specifically, we propose to revise the 1993 NCD 240.2 to expand the coverage of oxygen and oxygen equipment in the home for short as well as long term use in both acute and chronic diseases of respiratory and non-respiratory origin, as is medically necessary.  As mentioned above, we realize that the policy changes we are making to the 1993 NCD 240.2 will expand coverage of oxygen and oxygen equipment to beneficiaries with other conditions besides CH. We believe that this expansion is appropriate as it will remove limitations on reasonable and necessary treatments with home oxygen and oxygen equipment for beneficiaries.  As seen during the PHE, this will also give physicians more options to provide the best course of treatments, as is discussed further on in Section VI of this document.  

Below we outline the changes we propose to make to the pertinent sections of the 1993 NCD 240.2.  See Appendix B for the proposed NCD Manual language for NCD 240.2.2.  See Appendix C for the proposed NCD Manual language for the 1993 NCD 240.2.

General Statement of formatting changes
We intend to reformat the 1993 NCD 240.2 into the sections now more commonly used in NCDs: A (General); B (Nationally Covered Indications); C (Nationally Noncovered Indications); and D (Other). The chart below outlines the re-organization of NCD 240.2 into “modern” NCD format (see Appendix C for draft NCD Manual language).

N/A = not applicable

Section A (General)
Section A of the 1993 NCD 240.2 provides a broad summary of coverage of home use of oxygen which indicates that oxygen and oxygen equipment will only be covered for individuals with hypoxemia.^[1]  We have revised section A to more accurately reflect the current scope of the proposed NCD.  In the reconsideration of NCD 240.2, as noted above, we propose to expand the coverage of home use of oxygen to beneficiaries beyond the condition of chronic hypoxemia.  Therefore, we propose to modify Section A of the 1993 NCD 240.2 to reflect this change and additional changes that are discussed in the sections below.  

Section B, Medical Documentation
We are proposing to remove all of the language in Section B of the 1993 NCD 240.2 entitled Medical Documentation.  The main purpose of a NCD is to determine if items and services are reasonable and necessary for Medicare beneficiaries and will be covered (or non-covered) nationally under title XVIII.  CMS makes this determination by using an evidence based process which is responsive to comments of external stakeholders.  Determining appropriate documentation is not always part of the evidence-based analysis. 

As part of CMS effort to reduce provider burden, we are proposing to remove the oxygen CMN requirement from the NCD.  CMNs are claim attachment forms developed in the 1990s to augment medical review.  At that time the CMS DME claims systems had very limited editing capabilities and only basic information was included on the claim form.  The CMN forms captured information needed for medical necessity determinations.  Currently however, the claims processing system is more sophisticated and can secure information that may corroborate the medical necessity for home oxygen.  Sophisticated audits of the medical record may also accomplish the same goal.  Therefore we propose that the CMN for home oxygen is no longer required as part of the NCD.

We also acknowledge that in proposing to remove Section B of the 1993 NCD 240.2, we would be removing the following non-documentation requirement for home oxygen therapy: “The treating physician's prescription or other medical documentation must indicate that other forms of treatment (e.g., medical and physical therapy directed at secretions, bronchospasm and infection) have been tried, have not been sufficiently successful, and oxygen therapy is still required. While there is no substitute for oxygen therapy, each patient must receive optimum therapy before long-term home oxygen therapy is ordered.”  We believe it is clinically appropriate to remove this requirement because there are clinical circumstances for which this policy requirement is not relevant.  For example, treatment of CH in the otherwise healthy patient may not require other therapies.  As noted in the CPG of the VA/DoD, the use of inhaled oxygen may be first line therapy for CH in selected patients and if successful, is then in itself “optimum therapy.”  Therefore retaining a requirement for the prior use of alternative treatment may needlessly prolong patient symptoms and suffering in the individual with CH who does successfully respond to oxygen therapy.  Similarly, we believe that it is clinically inappropriate to withhold oxygen in the home for hypoxemic patients while awaiting the results of other therapeutic measures to take effect.  Though we believe it is the responsibility of the treating practitioner to evaluate any patient who requires oxygen in order to provide other therapeutic interventions as necessary, relief of signs and symptoms of respiratory insufficiency with supplemental oxygen, if reasonable and necessary, is paramount.

Section C (Laboratory Evidence)(Proposed as part of Section B (Nationally Covered Indications): General Expansion of Coverage and Removal of ‘Chronic Stable State’ Condition Criterion)

Section C of the 1993 NCD 240.2 similarly describes medical documentation requirements which we propose to remove for the same reasons as described above.  Specifically, we propose to remove in the fifth paragraph of Section C (proposed as Section B), the sentence, “A/B MACs (B) may accept an attending physician's statement of recent hospital test results for a particular patient, when appropriate, in lieu of copies of actual hospital records.”  This is a statement of a medical documentation requirement to demonstrate that a particular item or service meets a reasonable and necessary standard.  Documentation requirements such as this are more appropriately addressed in other manuals and guidance documents, not a NCD.

However, Section C of the 1993 NCD 240.2 also describes clinical criteria required to demonstrate that home oxygen was reasonable and necessary for the Medicare beneficiary.  We propose to revise these clinical criteria to increase access to home oxygen for beneficiaries with CH and other clinical conditions, when appropriate.

We propose to remove all references and instructions regarding the “chronic stable state,” in the 1993 NCD 240.2.  “Chronic stable state” is used in the NCD to describe illness or disease that is “not during a period of an acute illness or an exacerbation of their underlying disease.”  The characteristics of CH do not fit an illness or disease in its “chronic stable state,” because home oxygen is used to abort acute symptoms of CH, which in most cases would be expected to occur in bouts of relatively short duration (as compared to the symptoms of a life long chronic disease) and therefore only require short bursts of oxygen.  Further, by removing the clinical criterion of “chronic stable state” we will also expand the availability of home use of oxygen to individuals with resolving respiratory diseases who may benefit from oxygen in the short term (e.g. weeks instead of lifetime) as they recover from an acute, curable illness.  In a singular illustration of such a point, we note patients who may be recovering from COVID-19 associated pneumonia, but who do not or who no longer require hospitalization, may be cautiously managed to a satisfactory health outcome at home when oxygen therapy is available for relatively short periods of time (Cohen, 2020; Sardesai I, Grover J, Garg M, et al., 2020).  We believe this is clinically appropriate and therefore we propose to remove the requirement that home oxygen only be covered for those in the ‘chronic stable state’; and instead provide home use of oxygen for patients with medical need of any duration, both for acute or chronic diseases, as it is medically necessary.  

Because we propose to remove all references to the ‘chronic stable state’, we also propose that required qualifying blood gas studies be performed at the time of need.  The ‘time of need’ means during the patient’s illness when the presumption is that the provision of oxygen will improve the patient’s condition in the home setting, whether that condition represents a long term chronic illness or an expected short term recovery from an acute disorder.  For an inpatient hospital patient, this would ordinarily be (as currently stated in the 1993 NCD) within 2 days of discharge.  For those patients whose initial oxygen prescription does not originate during an inpatient hospital stay (such as individuals with CH), the time of need would logically be during the period when the treating practitioner notes signs and symptoms of illness that may be relieved by oxygen in the patient who is to be treated at home. 

Section D (Health Conditions) (portions Proposed in Section B (Nationally Covered Indications), Section C (Nationally Non-covered Indications), and D (Other))

As described below, we are proposing that Section D of the 1993 NCD 240.2 be rewritten to conform to the changes above.

Section D.1 of the 1993 NCD 240.2 (Conditions for Which Oxygen May Be Covered) provides the conditions and clinical criteria for which oxygen therapy may be covered and includes a list of specific examples of severe lung disease and hypoxia-related symptoms. We believe that by listing examples, which were not meant to be all-inclusive, we may have caused some to interpret the coverage determination more narrowly than intended.  Furthermore, as stated above, CMS recognizes that oxygen therapy in the home may be medically necessary to treat not just respiratory conditions, but also non-respiratory conditions for certain beneficiaries.  We noted above, for example, that it may be medically necessary to cover home oxygen therapy in order to diminish or terminate the exquisite pain of CH, a condition unrelated to the function of the lungs.  Even when oxygen therapy is required to support respiratory needs, the etiology of that need may be due to causes other than lung disease.  For example, chronic liver disease has long been known to be associated with respiratory symptoms and hypoxia for which the administration of supplemental oxygen may be appropriate (Maicao, Balakrishnan & Fallon, 2014).  Moreover, as noted above, the NCD should allow for maximum flexibility to clinically appropriately provide coverage of home oxygen and oxygen equipment, regardless of duration of need.  Therefore, we propose to remove the introduction to section D “Health Conditions” and Section D.1 (Conditions for which Oxygen May be Covered) of the 1993 NCD 240.2 including all examples of medical conditions that may require the use of home oxygen.  This change will reinforce that patients suffering from any medical condition, be it of respiratory or non-respiratory origin, may receive home oxygen and oxygen equipment for the duration of illness, be it short or long term, if this service is otherwise reasonable and necessary.

We also propose to make the conforming change noted above removing the need for the patient to have unsuccessfully tried alternative therapies prior to the use of oxygen in the home (bullet D.3 of the 1993 NCD 240.2).  As noted above, oxygen may be used as first line therapy for the treatment of CH.  We believe that this bullet is an obstacle to ensuring the opportunity for local coverage discretion for the treatment of this condition, when appropriate.  However, we again emphasize that it is the responsibility of the treating practitioner to fully evaluate the patient who requires oxygen and provide other therapeutic interventions as necessary.

We propose to move Section D.2 of the 1993 NCD 240.2 (Conditions for Which Oxygen Therapy Is Not Covered) to proposed Section C (Nationally Noncovered Indications).  Under subsection D2 of the 1993 NCD 240.2, Conditions for Which Oxygen Therapy Is Not Covered (Proposed as Section C, National Noncovered Indications), we also propose to modify bullet 4, the sentence stating that among illnesses not covered are “terminal illnesses that do not affect the lungs,” to instead say “terminal illnesses that do not affect the ability to breathe.”  As stated above, CMS recognizes that respiratory function can be impaired from various causes, not all of which involve primary lung disease and we want to ensure Medicare patients receive medically necessary treatments.

Further, for those patients who exceed the SPO2 and/or oxygen saturation values of the Group I and II individuals described in Section D of the 1993 NCD 240.2, coverage of home oxygen is proposed to be at the discretion of the MACs for the reasons discussed above.  As stated throughout this NCA, patients experiencing CH would be expected to typically fall under this category.  Therefore we propose to revise the language in Group III in section D.3.c of the 1993 NCD 240.2 and (here proposed as new section D (Other) to remove the current reference to Group III and the definition including the rebuttable presumption of noncoverage. We propose to replace it with the following sentence:  The MAC may determine the reasonable and necessary coverage of home oxygen and oxygen equipment for patients with conditions unrelated to hypoxemia.  These conditions include CH, for which blood gas levels are not required, and other disease states that demonstrate arterial pO2 levels at or above 60 mm Hg, or arterial blood oxygen saturation at or above 90%. 

For those patients with hypoxemia, recertification requirements are specified per local coverage determination.  For those individuals who are not hypoxemic or who demonstrate continued recovery from an acute disease, we propose that initial coverage be limited to the shorter of 90 days or physician prescription.  However for this subset of patients, we also propose oxygen coverage may be renewed if medically necessary when a treating practitioner determines within 60-90 days after the DME has been initially placed in the home that the patient exhibits a continuing need for oxygen.  This period of time has been chosen because clinically, we expect most patients (excluding those with CH) recovering from acute diseases that have required the use of home oxygen, to no longer have need for this medical gas.  Additionally, in Covered Blood Gas Values, section D.3.a of the 1993 NCD 240.2 (proposed as section B.2), we note the term ‘exercise’ in the requirements for Group I patients, in the past, may have been interpreted by some narrowly.  We propose the term exercise should be interpreted more broadly to include either the functional performance of the patient (e.g. ambulation, accomplishment of ADLs, stair climbing, dressing, eating, etc.) or a formal exercise test (e.g. 6 minute walk test, etc.), as preferred by the treating practitioner.  Given the burden that respiratory illnesses places on the patient during everyday activities, the need for oxygen can be evaluated during the execution of these routine pursuits.

Based on the discussion below regarding health disparities, we also propose to modify section D.3.d of the 1993 NCD 240.2 (Variable Factors That May Affect Blood Gas Values) in order to add the patient’s skin pigmentation to the list of factors that may account for variations in oxygen measurement.  The subheading is removed and the language is moved to the end of proposed Section B, Nationally Covered Indications.  Finally, we also propose to remove Section F from the 1993 NCD 240.2 concerning Respiratory Therapists.  As the DME benefit does not include clinical services, we believe that having this section as part of the NCD is not necessary.

Health Disparities

Pulse oximetry can be a useful means to estimate blood oxygen levels.  However, the FDA states that there are individual variations among patients when tested with pulse oximeters and therefore the device reading should always be considered an estimate of oxygen saturation.  For example, if an FDA-cleared pulse oximeter reads 90%, then the true oxygen saturation in the blood is generally between 86-94%.  Pulse oximeter accuracy is highest at saturations of 90-100%, intermediate at 80-90%, and lowest below 80% (FDA, 2021).

Patient factors may affect the exactness of this measurement.  For example, literature has reported that there are differences in the accuracy of the pulse oximeter readings when the information obtained from these devices is compared between persons who identified their race as Black or White.  Though many of the individuals who identified themselves as Black did demonstrate accurate pulse oximeter values, their risk of experiencing occult hypoxemia (defined as an arterial oxygen saturation of <88% determined by arterial blood gas studies despite an oxygen saturation of 92 to 96% on pulse oximetry) was reported to be nearly three times that of individuals who designated themselves as White (Sjoding, 2020).

It is important for both patients and providers to be aware of the limitations of pulse oximeters, particularly when these devices are used to either diagnose or treat conditions that require the ongoing monitoring of the patient’s health status as oxygen is used in the home.  All manifestations of an individual’s disease state and physical characteristics should be considered in their assessment, including signs and symptoms of cognitive and physical dysfunction, potential laboratory abnormality, and variability of device readings.  The discretion provided to the MACs in this NCD should provide home oxygen coverage for all individuals who require it.

Technical Changes

Based on the above mentioned reformatting into an A-D structure, we propose several conforming technical changes.  The language of Section E (Portable Oxygen Systems) of the 1993 NCD 240.2 would be moved to Section D (Other) because it reflects local coverage discretion.  

IX.   Conclusion

CMS is proposing changes to two separate, but medically related, NCDs.  Given new information in the peer-reviewed medical literature, we are removing NCD for Home Oxygen Use to Treat CH (240.2.2).  We are also revising NCD for Home Use of Oxygen (240.2) based on our removing of the Home Oxygen Use to Treat CH.  We summarize these changes below and fully explain our rationale in the Analysis section of this NCD decision memo.

CMS proposes to remove its NCD at section 240.2.2 of the Medicare NCD Manual, ending coverage with evidence development, and allow the MACs to make coverage determinations regarding the use of home oxygen and oxygen equipment for CH.

CMS also proposes to modify its NCD for Home Use of Oxygen at section 240.2 of the Medicare NCD Manual to expand patient access to oxygen and oxygen equipment in the home, and to permit contractors to cover the use of home oxygen and oxygen equipment in treating CH and other acute conditions.  

The scope of this decision does not include any consideration of Home Use of Oxygen in Approved Clinical Trials, identified in section 240.2.1 of the NCD manual.  Additionally, the scope of the decision does not include any consideration of hyperbaric oxygen for any indication, currently identified in section 20.29 of the NCD manual.

See Appendices B and C for proposed NCD Manual language.

When making national coverage determinations, CMS evaluates relevant clinical evidence to determine whether or not the evidence is of sufficient quality to support a finding that an item or service is reasonable and necessary. The overall objective for the critical appraisal of the evidence is to determine to what degree we are confident that: 1) the specific assessment questions can be answered conclusively; and 2) the intervention will improve health outcomes for patients.

We divide the assessment of clinical evidence into three stages: 1) the quality of the individual studies; 2) the generalizability of findings from individual studies to the Medicare population; and 3) overarching conclusions that can be drawn from the body of the evidence on the direction and magnitude of the intervention’s potential risks and benefits.

The methodological principles described below represent a broad discussion of the issues we consider when reviewing clinical evidence. However, it should be noted that each coverage determination has its unique methodological aspects.

Assessing Individual Studies

Methodologists have developed criteria to determine weaknesses and strengths of clinical research. Strength of evidence generally refers to: 1) the scientific validity underlying study findings regarding causal relationships between health care interventions and health outcomes; and 2) the reduction of bias. In general, some of the methodological attributes associated with stronger evidence include those listed below:

• Use of randomization (allocation of patients to either intervention or control group) in order to minimize bias.
• Use of contemporaneous control groups (rather than historical controls) in order to ensure comparability between the intervention and control groups.
• Prospective (rather than retrospective) studies to ensure a more thorough and systematical assessment of factors related to outcomes.
• Larger sample sizes in studies to demonstrate both statistically significant as well as clinically significant outcomes that can be extrapolated to the Medicare population. Sample size should be large enough to make chance an unlikely explanation for what was found.
• Masking (blinding) to ensure patients and investigators do not know to that group patients were assigned (intervention or control). This is important especially in subjective outcomes, such as pain or quality of life, where enthusiasm and psychological factors may lead to an improved perceived outcome by either the patient or assessor.

Regardless of whether the design of a study is a randomized controlled trial, a non-randomized controlled trial, a cohort study or a case-control study, the primary criterion for methodological strength or quality is to the extent that differences between intervention and control groups can be attributed to the intervention studied. This is known as internal validity Various types of bias can undermine internal validity. These include:

• Different characteristics between patients participating and those theoretically eligible for study but not participating (selection bias).
• Co-interventions or provision of care apart from the intervention under evaluation (performance bias).
• Differential assessment of outcome (detection bias).
• Occurrence and reporting of patients who do not complete the study (attrition bias).

In principle, rankings of research design have been based on the ability of each study design category to minimize these biases. A randomized controlled trial minimizes systematic bias (in theory) by selecting a sample of participants from a particular population and allocating them randomly to the intervention and control groups. Thus, in general, randomized controlled studies have been typically assigned the greatest strength, followed by non-randomized clinical trials and controlled observational studies. The design, conduct and analysis of trials are important factors as well. For example, a well-designed and conducted observational study with a large sample size may provide stronger evidence than a poorly designed and conducted randomized controlled trial with a small sample size. The following is a representative list of study designs (some of that have alternative names) ranked from most to least methodologically rigorous in their potential ability to minimize systematic bias:

Randomized controlled trials
Non-randomized controlled trials
Prospective cohort studies
Retrospective case control studies
Cross-sectional studies
Surveillance studies (e. g. , using registries or surveys)
Consecutive case series
Single case reports

When there are merely associations but not causal relationships between a study’s variables and outcomes, it is important not to draw causal inferences. Confounding refers to independent variables that systematically vary with the causal variable. This distorts measurement of the outcome of interest because its effect size is mixed with the effects of other extraneous factors. For observational, and in some cases randomized controlled trials, the method in that confounding factors are handled (either through stratification or appropriate statistical modeling) are of particular concern. For example, in order to interpret and generalize conclusions to our population of Medicare patients, it may be necessary for studies to match or stratify their intervention and control groups by patient age or co-morbidities.

Methodological strength is, therefore, a multidimensional concept that relates to the design, implementation and analysis of a clinical study. In addition, thorough documentation of the conduct of the research, particularly study selection criteria, rate of attrition and process for data collection, is essential for CMS to adequately assess and consider the evidence.

Generalizability of Clinical Evidence to the Medicare Population

The applicability of the results of a study to other populations, settings, treatment regimens and outcomes assessed is known as external validity. Even well-designed and well-conducted trials may not supply the evidence needed if the results of a study are not applicable to the Medicare population. Evidence that provides accurate information about a population or setting not well represented in the Medicare program would be considered but would suffer from limited generalizability.

The extent to that the results of a trial are applicable to other circumstances is often a matter of judgment that depends on specific study characteristics, primarily the patient population studied (age, sex, severity of disease and presence of co-morbidities) and the care setting (primary to tertiary level of care, as well as the experience and specialization of the care provider. Additional relevant variables are treatment regimens (dosage, timing and route of administration), co-interventions or concomitant therapies, and type of outcome and length of follow-up.

The level of care and the experience of the providers in the study are other crucial elements in assessing a study’s external validity. Trial participants in an academic medical center may receive more or different attention than is typically available in non-tertiary settings. For example, an investigator’s lengthy and detailed explanations of the potential benefits of the intervention and/or the use of new equipment provided to the academic center by the study sponsor may raise doubts about the applicability of study findings to community practice.

Given the evidence available in the research literature, some degree of generalization about an intervention’s potential benefits and harms is invariably required in making coverage determinations for the Medicare population. Conditions that assist us in making reasonable generalizations are biologic plausibility, similarities between the populations studied and Medicare patients (age, sex, ethnicity and clinical presentation) and similarities of the intervention studied to those that would be routinely available in community practice.

A study’s selected outcomes are an important consideration in generalizing available clinical evidence to Medicare coverage determinations. One of the goals of our determination process is to assess health outcomes. These outcomes include resultant risks and benefits such as increased or decreased morbidity and mortality. In order to make this determination, it is often necessary to evaluate whether the strength of the evidence is adequate to draw conclusions about the direction and magnitude of each individual outcome relevant to the intervention under study. In addition, it is important that an intervention’s benefits are clinically significant and durable, rather than marginal or short-lived. Generally, an intervention is not reasonable and necessary if its risks outweigh its benefits.

If key health outcomes have not been studied or the direction of clinical effect is inconclusive, we may also evaluate the strength and adequacy of indirect evidence linking intermediate or surrogate outcomes to our outcomes of interest.

Assessing the Relative Magnitude of Risks and Benefits

Generally, an intervention is not reasonable and necessary if its risks outweigh its benefits. Health outcomes are one of several considerations in determining whether an item or service is reasonable and necessary. CMS places greater emphasis on health outcomes actually experienced by patients, such as quality of life, functional status, duration of disability, morbidity and mortality, and less emphasis on outcomes that patients do not directly experience, such as intermediate outcomes, surrogate outcomes, and laboratory or radiographic responses. The direction, magnitude, and consistency of the risks and benefits across studies are also important considerations. Based on the analysis of the strength of the evidence, CMS assesses the relative magnitude of an intervention or technology’s benefits and risk of harm to Medicare beneficiaries.

240.2  Home Use of Oxygen

Initial claims for oxygen therapy for hypoxemic patients must be based on the results of a clinical test that has been ordered and evaluated by the treating practitioner.  Such a test is usually in the form of a measurement of the partial pressure of oxygen (PO2) in arterial blood.  A measurement of arterial oxygen saturation obtained by ear or pulse oximetry, however, is also acceptable when ordered and evaluated by the treating practitioner and performed under his or her supervision or when performed by a qualified provider or supplier of laboratory services. A durable medical equipment (DME) supplier is not considered a qualified provider or supplier of laboratory services for purposes of these guidelines.  This prohibition does not extend to the results of blood gas test conducted by a hospital certified to do such tests.

When the arterial blood gas and the oximetry studies are both used to document the need for home oxygen therapy and the results are conflicting, the arterial blood gas study is the preferred source of documenting medical need.  

Required qualifying blood gas studies must be performed at the time of need.  The time of need is defined as during the patient’s illness when the presumption is that the provision of oxygen will improve the patient’s condition in the home setting. For an inpatient hospital patient anticipated to require oxygen upon going home, the time of need would be within 2 days of discharge. For those patients whose initial oxygen prescription does not originate during an inpatient hospital stay, the time of need would be during the period when the treating practitioner notes signs and symptoms of illness that can be relieved by oxygen in the patient who is to be treated at home. 

Another blood gas or oximetry study may be performed when the oxygen recipient has a major change in his/her condition relevant to home use of oxygen. 

Coverage of home oxygen and oxygen equipment shall be provided for hypoxemic individuals when the below clinical criteria of Group I or Group II are met:

Group 1:

• An arterial PO2 at or below 55 mm Hg, or an arterial oxygen saturation at or below 88%, taken at rest, breathing room air; or
• An arterial PO2 at or below 55 mm Hg, or an arterial oxygen saturation at or below 88%, taken during sleep for a patient who demonstrates an arterial PO2 at or above 56 mm Hg, or an arterial oxygen saturation at or above 89%, while awake; or a greater than normal fall in oxygen level during sleep (a decrease in arterial PO2 more than 10 mm Hg, or decrease in arterial oxygen saturation more than 5%) associated with symptoms or signs reasonably attributable to hypoxemia (e.g., impairment of cognitive processes and nocturnal restlessness or insomnia).  In either of these cases, coverage is provided only for use of oxygen during sleep, and then only one type of unit will be covered.  Portable oxygen, therefore, would not be covered in this situation; or
•   An arterial PO2 at or below 55 mm Hg or an arterial oxygen saturation at or below 88%, taken during exercise [defined as either the functional performance of the patient or a formal exercise test], for a patient who demonstrates an arterial PO2 at or above 56 mm Hg, or an arterial oxygen saturation at or above 89%, during the day while at rest.  In this case, supplemental oxygen is provided for during exercise if the use of oxygen improves the hypoxemia that was demonstrated during exercise when the patient was breathing room air.

Group II:   Coverage is available for patients whose arterial PO2 is 56-59 mm Hg or whose arterial blood oxygen saturation is 89%, if there is:

• Dependent edema suggesting congestive heart failure; or,
• Pulmonary hypertension or cor pulmonale, determined by measurement of pulmonary artery pressure, gated blood pool scan, echocardiogram (EKG), or "P" pulmonale on EKG (P wave greater than 3 mm in standard leads II, III, or AVFL; or,
• Erythrocythemia with a hematocrit greater than 56%.

In reviewing the arterial PO2 levels and the arterial oxygen saturation percentages specified above, the MAC must take into account variations in oxygen measurements that may result from such factors as the patient's age, the patient’s skin pigmentation, the altitude level, or the patient's decreased oxygen carrying capacity.

• Angina pectoris in the absence of hypoxemia. This condition is generally not the result of a low oxygen level in the blood, and there are other preferred treatments;
• Breathlessness without cor pulmonale or evidence of hypoxemia. Although intermittent oxygen use is sometimes prescribed to relieve this condition, it is potentially harmful and psychologically addicting;
• Severe peripheral vascular disease resulting in clinically evident desaturation in one or more extremities. There is no evidence that increased PO₂ improves the oxygenation of tissues with impaired circulation; or
• Terminal illnesses that do not affect the ability to breathe.

Cross Reference

(See §280.1 and the Medicare Benefit Policy Manual, Chapter 15, “Covered Medical and Other Health Services,” §110.)

[1] Section A of NCD 240.2 (effective 10/27/1993) states: Medicare coverage of home oxygen and oxygen equipment under the DME benefit (see §1861(s)(6) of the Social Security Act) is considered reasonable and necessary only for patients with significant hypoxemia who meet the medical documentation, laboratory evidence, and health conditions …”

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