The Importance of Expanding Medicare Continuous Glucose Monitoring Coverage for High-Risk Hypoglycemia

Introduction

Continuous glucose monitoring (CGM) technology has significantly impacted the management of diabetes. CGM provides patients with immediate feedback on glucose levels and excursions stemming from dietary choices, exercise, and insulin doses. CGM functions as a constant, personalized educator, helping patients maintain optimal glucose levels while avoiding severe hyperglycemia and hypoglycemia. Patient glucose tracings and metrics can be easily accessed by treating clinicians, facilitating the creation of individualized treatment plans. The volume of data supporting the use of CGM is so compelling that the American Diabetes Association recommends its use for all patients using insulin as well as those who do not use insulin but take other glucose-lowering medications. ¹

The Centers for Medicare & Medicaid Services (CMS) began covering continuous glucose monitors for a limited population in early January 2017. ² As evidence justifying CGM use in expanded populations has emerged, CMS has accordingly kept pace in updating policies and coverage. The current policy allows individuals who use any insulin, or who do not use insulin but experience significant hypoglycemic events in the setting of diabetes management, to access CGM coverage. ³

One of the current coverage criteria for CGM is that the beneficiary has diabetes mellitus, as defined by a long list of International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10-CM) diagnostic codes contained in an associated “Policy Article.” ⁴ Another criterion is that the CGM needs to be prescribed in accordance with its Food and Drug Administration (FDA) indications for use. While these criteria seem generally reasonable, they restrict access to CGM by patients with a range of conditions that give rise to serious dysglycemic events, in particular high-risk, life-threatening hypoglycemia. This article describes why these limitations exist, categories of patients with hypoglycemic conditions beyond diabetes that might benefit from CGM use, and how CMS could modify CGM coverage criteria to permit access to this important technology by those patients.

Policy Background

CMS uses entities known as Medicare Administrative Contractors (MACs) to process claims and make determinations regarding when items and services are “reasonable and necessary” ⁵ and thus eligible for Medicare coverage. Rather than making such determinations on a case-by-case basis, MACs may establish a Local Coverage Determination (LCD) defining when an item or service will be consistently considered reasonable and necessary. The authority for MACs to generate LCDs stems from Section 1869(f)(2) of the Social Security Act and is elaborated in the Medicare Program Integrity Manual, which clarifies that when developing an LCD, MACs must abide by “all statutes, rulings, regulations, and national coverage, payment, and coding policies.” ⁶ LCDs apply only to the geographic area over which the MAC has jurisdiction. Presently, there are two organizations (CGS Administrators, LLC, and Noridian Healthcare Solutions) that each have two of the available four jurisdictions for purposes of processing claims for durable medical equipment (DME) and establishing related LCDs. CGS and Noridian work closely together when establishing LCDs, so that their decisions effectively form a single national coverage policy.

In September 2021, a group of diabetes stakeholders, including several of the authors of this article, submitted a formal request to the DME MACs, asking that they expand Medicare’s coverage of CGM to different populations, including individuals without diabetes who “have undergone bariatric surgery or have other rare causes of hypoglycemia.” ⁷ When the DME MACs issued a proposed LCD in response to this request, they stated that:

In response to this denial, commentators questioned the applicability of NCD 40.2 to CGMs since NCD was first issued many years before the emergence of CGM technology and describes blood glucose test strip technology in detail, rather than CGM technology. ⁹ In the final LCD, the DME MACs did not respond to the line of reasoning that NCD 40.2 should not apply to CGM. Instead, to continue justifying their refusal to expand coverage beyond diabetes, they pointed to the preamble of a CMS regulation issued on December 28, 2021. In that preamble, CMS states that, “Because certain CGMs have been approved or cleared by the FDA to replace blood glucose monitors for use in making diabetes treatment decisions, we believe that CGMs represent a newer technology version of glucose monitors paid for by Medicare in 1986 and 1987.” ¹⁰ The MACs emphasized that this preamble language noted that CGM was FDA approved for use in making “diabetes treatment decisions.” It appears that they interpreted this language as a limitation on the use of CGM to patients with diagnosed diabetes, even though the preamble’s language does not explicitly establish such a limitation. Rather, the preamble simply notes the nature of the FDA approvals for CGM. The DME MACs went a step further by including a new coverage criterion for CGM, restricting its use only to situations when it is prescribed in accordance with an FDA-approved indication for its use. Although prior versions of the LCD were compatible with the requirement to use CGM in accordance with an FDA-approved indication, this explicit requirement did not previously exist, and it is unclear why the DME MACs included it in the final LCD.

It would appear, therefore, that two obstacles stand in the way of expanding Medicare’s coverage of CGM to populations who do not have diabetes: first, NCD 40.2, and second, the DME MAC’s ruling specifying use of CGM solely for an FDA-approved use. We note that the three CGMs currently covered under the Medicare DME benefit have all been FDA approved solely for the management of diabetes.^11–13

CMS’ Coverage and Analysis Group (CAG) is the entity responsible for revising or rescinding NCDs. They can begin that process on their own or pursuant to a request from an interested party. Unfortunately, CMS CAG is known to be under-resourced relative to its important workload, and recent reductions in the federal workforce are likely to exacerbate this challenge. ¹⁴ CMS CAG must necessarily make determinations as to which policies it takes up for review, based on their evaluation of the impact of those coverage policies on the Medicare program and its beneficiaries. CAG currently has a substantial waitlist for such revisions, with some requests languishing for years. ¹⁵ Given their capacity restrictions, the most efficient approach for CAG to address the question of CGM coverage for patient groups without diabetes but with other specified conditions would be to rescind NCD 40.2 and permit the DME MACs to make determinations as to the medical necessity of CGM for these populations through the LCD process, since the DME MACs have the resources to move much more expeditiously. In doing so, we recommend that CMS CAG acknowledge the potential value of CGM use by some groups of people without diabetes, without deciding as to whether such use would be reasonable and necessary and clarify that they intend for the DME MACs to make these determinations.

The DME MACs recognize that hypoglycemic events in people with diabetes can be serious and life-threatening, as demonstrated by their decision to permit coverage of CGM for people with diabetes who do not use insulin, but who experience Level 2 or Level 3 hypoglycemic events. For reasons explained below, we believe that once CMS’ CAG rescinds NCD 40.2, no statutory, regulatory, or subregulatory policy provision would prevent the DME MACs from extending CGM coverage to conditions outside of diabetes for which they deem such coverage to be reasonable and necessary.

There are several reasons to believe that the DME MACs could remove the requirement for using CGM only for FDA-approved indications. First, and foremost, the DME MACs did not include this requirement in the CGM LCD for several years. Its inclusion was not occasioned by a change in law, regulation, or CMS policy, so the DME MACs could revert to the earlier state of not including that criterion.

The definition of DME, in Section 1861(n) of the Social Security Act, does not include a restriction on covering items only for FDA-approved indications. CMS elaborated on the statutory definition in the regulation at 42 Code of Federal Regulations 410.38, but again did not restrict coverage of DME to only FDA-approved indications. The foundation of Medicare coverage is the provision of Section 1862(a)(1)(A) of the Social Security Act, which requires that items and services be “reasonable and necessary.” CMS has, over the years, taken great pains to clarify that this basis of coverage differs from the “safe and effective” standard used by the FDA and that while Medicare coverage decisions are informed by the decisions of FDA, they are not controlled by them. ¹⁶

Section 13.5.4 of Chapter 13 of the Medicare Program Integrity Manual details CMS’ interpretation of what it means for an item or service to be “reasonable and necessary”; this document does not restrict Medicare coverage to only FDA-indicated applications. ¹⁷ Similarly, Section 110.1.C.1 of Chapter 15 of the Medicare Benefits Policy Manual addresses requirements for DME coverage under the heading “Necessary and Reasonable”:

Thus, nowhere in law, regulation, or subregulatory guidance does CMS articulate a requirement that DME be covered only when prescribed in accordance with an FDA-approved indication for use. The DME MACs went beyond the statute, regulation, and policy manuals in creating such a requirement for CGM coverage.

The DME MACs have issued 58 LCDs. ¹⁹ Among them, there are very limited mentions of FDA approvals. The LCDs for immune globulin, ²⁰ inhaled solutions delivered via nebulizer, ²¹ an oral anti-emetic 3-drug combination, ²² and immunosuppressive drugs ²³ all require that these medications be used for an FDA-approved indication to secure Medicare coverage. Notably, these LCDs concern themselves with medications, not medical equipment. Regarding medical equipment, there are LCDs for oral appliance devices ²⁴ and positive airway pressure devices ²⁵ for the treatment of obstructive sleep apnea as well as respiratory assist devices ²⁶ that limit coverage for these devices to situations where the beneficiary has completed an FDA-approved sleep test, but do not have a requirement that the device itself be ordered only for an FDA-approved indication. Finally, the LCD for parenteral nutrition provides for coverage of protein, dextrose, or lipid orders in excess of the product-specific FDA-approved dosing recommendation when certain conditions are met. ²⁷ Thus, aside from the CGM LCD, there is no other LCD for medical equipment limiting coverage to situations when the device is used in accordance with an FDA-approved indication. If applicable law, regulation, or subregulatory policy required such a provision, it would be present in each LCD for medical equipment. Since there is no such provision in these controlling documents, and as they have not done so with any other medical equipment LCD, the DME MACs can remove it from the CGM LCD.

Once these two policy obstacles have been addressed, the pathway is open for interested stakeholders to request that the DME MACs determine when use of CGM would be reasonable and necessary for high-risk nondiabetic conditions. Some of these conditions are described below.

Clinical Considerations

Perhaps the clearest examples of high-risk conditions in patients without diabetes where CGM use would be appropriate are those that cause recurrent severe hypoglycemia. Persons with conditions that predispose them to severe hypoglycemia are at risk for loss of consciousness, seizures, and death from very low glucose levels. Severe hypoglycemia can be prevented with earlier recognition and treatment, as has been shown for individuals with diabetes. Requiring a clinical trial to prove the need for glucose monitoring in additional conditions would be unnecessary and potentially unethical. Clinicians routinely recommend and prescribe CGM for persons with these disorders for their potential life-saving benefits; however, when the primary payer is Medicare, CGM is not covered, and patients are forced to pay out of pocket or they may not be able to access devices that are medically indicated.

One such condition that predisposes patients to severe hypoglycemia is postbariatric hypoglycemia (PBH), which occurs after multiple types of upper gastrointestinal surgery. There is now a body of published evidence demonstrating that some patients experience unexpected, severe hypoglycemic events after the surgery. One study found rates of hypoglycemia in postbariatric surgery patients of between 66% and 75%, depending on the measurement tool used, with more than a third of patients experiencing glucose levels less than 54 mg/dL or level 2 hypoglycemia. ²⁸ While the pathophysiology of this condition is complex, ultimately dysregulated and markedly increased secretion of insulin by the pancreas after meals and reduced secretion of counter-regulatory hormones result in a very rapid decrease in glucose. In addition, patients can experience hypoglycemia with exercise and during overnight hours. Moreover, these patients can have recurrent level 3 hypoglycemia requiring assistance from another person and can develop hypoglycemia unawareness, further impairing their safety. For example, a recent study found that 87% of participants with PBH reported level 3 hypoglycemia, with emergency room visits in 28% and motor vehicle accidents in 8% of participants. Reduced awareness was reported by 82%, and 13%–17% were classified as hypoglycemia unaware, as per the modified Clarke–Gold scores. ²⁹

The reality of this challenge and the lack of consistently effective therapies for this condition have prompted the American Diabetes Association to include in its Standards of Care in Diabetes a recommendation that CGMs be used to track patient glucose levels after bariatric surgery. Recommendation 8.25 states that “In individuals with post-metabolic surgery hypoglycemia, use continuous glucose monitoring to improve safety.” ³⁰ The UK Society for Endocrinology and the European Society of Endocrinology have recommended that “CGM, where available or funded, may be considered as a tool for education, reinforcing and documenting the relationship between dietary changes to the amelioration of PBH [post-bariatric hypoglycemia].” ³¹

Several studies have examined the use of CGM after bariatric surgery and provide the basis for the use of this tool in that population.

A 2025 study of the impact of CGM on hypoglycemia and quality of life, among PBH patients, randomized individuals in random order to use of unmasked CGM—able to see the sensor data in real time and receive alerts for both high and low sensor glucose—or masked CGM, when they were not able to see the data or receive alerts. Strikingly, there was a six-fold reduction in hypoglycemic events (P = 0.008) when patients were provided the CGM data and alerts. Moreover, the minimum glucose level when using unmasked CGM was >8 mg/dL higher (P = 0.005) than when CGM use was unmasked. In addition, patient scores on the Hypoglycemia Fear Survey-II significantly improved with unmasked CGM use (P = 0.026). ³²

These studies found that hypoglycemia is a common occurrence in the postbariatric surgery population and that the use of CGM is effective in helping these patients to avoid hypoglycemic events. For patients with hypoglycemia unawareness, CGM technology provides alerts to warn patients of their impending hypoglycemia with sufficient time to institute treatment and thus prevent more severe hypoglycemia. This evidence, along with the existing standard of care, provides support for the DME MACs to extend coverage of CGM to this population.

In addition to patients undergoing bariatric surgery, several other nondiabetic conditions are known to give rise to severe hypoglycemia such as glycogen storage diseases (GSDs), ³⁹ kidney ⁴⁰ and liver ⁴¹ failure, neuroendocrine tumors (insulinomas) that secrete insulin, ⁴² other forms of tumor-associated hyperinsulinism, and autoimmune causes of hypoglycemia.^43,44 In each of these conditions, hypoglycemia occurs in an unpredictable pattern, making it impossible for patients to anticipate and/or prevent severe hypoglycemia events.

GSDs affect 1 in 20,000–40,000 people and are autosomal recessive disorders. Mutations in key genes regulating glycogen metabolism or gluconeogenesis lead to the accumulation of glycogen in the liver and other tissues and reduced ability of the liver to breakdown glycogen or produce glucose, which is necessary to maintain blood glucose levels. Persons with GSD type 1a and 1 b have an extremely high risk for severe hypoglycemia from infancy onward. Supplemental cornstarch and other dietary maneuvers can reduce but not abolish hypoglycemia, and around-the-clock vigilance is needed for rapid treatment to avoid seizures. CGM has been used as a mainstay for these patients’ safety and is recommended by pediatric societies.^45,46

Patients with liver failure and kidney failure are at risk for hypoglycemia due to impaired gluconeogenesis or poor nutritional status coupled with prolonged half-life of insulin. ⁴¹ Definitive treatment of liver failure is liver transplantation; however, keeping patients neurologically intact requires avoidance of hypoglycemia. Similarly, patients with end-stage kidney disease on hemodialysis who demonstrate episodic hypoglycemia without diabetes or diabetes treatment require surveillance and immediate treatment of low glucose levels. ⁴⁰ Insulinoma is an uncommon neuroendocrine tumor that is often benign and cured by surgical excision. However, those with metastatic disease or other tumors that secrete insulin-like substances may continue to have hypoglycemia despite chemotherapy, targeted embolization, and medications to reduce insulin secretion or action, such as diazoxide or somatostatin analogs. Patient survival is typically 2.5–10 years, but quality of life is impaired by recurrent severe hypoglycemia. ⁴⁷

Adults with unexplained hypoglycemia despite extensive diagnostic investigation may have an autoimmune cause for their hypoglycemia, typically from autoantibodies to the insulin receptor or to insulin itself.^43,48,49 Immunosuppression may not be 100% effective, leaving the patient at risk for severe hypoglycemia. Management of hypoglycemia involves surveillance with CGM and immediate treatment. In all of these nondiabetic conditions, CGM has a life-saving role and is commonly used as an adjunct to definitive therapy.

Under the existing restriction imposed by NCD 40.2, no matter how compelling the relevant clinical evidence may be, or how well-supported it is by applicable standards of care, the DME MACs will not be able to permit use of CGM by patients with any of these conditions, despite their risk of severe hypoglycemia. In the interest of ensuring that these vulnerable patients have access to critical technology, we encourage CMS’s CAG to rescind NCD 40.2 and turn over to the DME MACs the responsibility for considering evidence and establishing CGM coverage criteria for relevant nondiabetic populations at risk for severe hypoglycemic events.

Authors’ Contributions

M.E.P.: Conceptualization, writing—original draft, and writing—review and editing. G.A.: Writing—review and editing. D.K.: Writing—review and editing. C.J.L.: Writing—review and editing. J.B.: Conceptualization, writing—original draft, writing—review and editing, and project administration. G.U.: Writing—review and editing. R.J.G.: Writing—review and editing. G.P.F.: Writing—review and editing. A.L.C.: Writing—review and editing. J.B.M.: Conceptualization, writing—original draft, and writing—review and editing.