Large National Claims Analysis Underscores Gap Between CGM Eligibility and Real-World Use in Diabetes Care

In a real-world analysis of more than 3.1 million adults with insulin-treated diabetes drawn from a large, national claims database, most individuals who met clinical criteria for continuous glucose monitoring (CGM) had no evidence of using the technology, exposing a significant gap in uptake of the technology despite recent updates to federal coverage policy that expand the eligible population.¹

"After applying all inclusion and exclusion criteria, 3,139,979 individuals in our study population were eligible for CGM; however, 83% had no evidence of use, indicating low uptake despite eligibility," investigators wrote. The finding is particularly concerning given the magnitude and consistency of benefits the study revealed among CGM users and the US health care system.

In the matched analysis of nearly 940,000 adults with insulin-treated diabetes, senior author Irl B Hirsch, MD, medical cirector of the Diabetes Care Center of the University of Washington Medical Center, and colleauges reportred that total 12-month health care costs averaged $6,245 among CGM users versus $7,786 among nonusers (P <.001). CGM use was also associated with fewer emergency department (ED) and inpatient (IP) days at 3, 6, 9, and 12 months, as well as lower rates of encounters related to hypoglycemia, diabetic ketoacidosis (DKA), or both. CGM users also had 19% higher odds of achieving an HbA1c level below 9%, a threshold commonly used by payers and quality programs to define poor control.

The study, published in Diabetes Technology & Therapeutics, evaluated clinical and economic outcomes among adults prescribed prandial insulin, a population at heightened risk for glycemic variability and acute complications.

The Cost of Diabetes in the US

Diabetes affects an estimated 38.4 million people in the United States,² with nearly 10 million treated with insulin.³ Despite decades of therapeutic advances, only about one-quarter of individuals with type 1 diabetes or insulin-treated type 2 diabetes achieve the recommended HbA1c target of less than 7%,⁴ while diabetes-related costs now exceed $413 billion annually.⁵ Acute events requiring hospitalization or ED care account for a growing share of that burden.⁶

CGM systems provide continuous glucose data, trend information, and alerts for hypo- and hyperglycemia, enabling earlier intervention than traditional fingerstick testing. A preponderance of randomized trials and observational studies have linked CGM use to improved glycemic outcomes and reduced acute care utilization, leading professional societies to recommend CGM for most insulin-treated patients.^7,8 However, real-world uptake remains inconsistent, influenced by coverage restrictions, administrative barriers, and disparities in access.

Study Elements

Hirsch et al conducted a retrospective matched cohort analysis using the Mariner Commercial Claims Database, which includes de-identified claims from approximately 161 million individuals across payer types. Adults aged 18 years or older with a diagnosis of type 1 or type 2 diabetes and at least one claim for rapid- or short-acting insulin in early 2021 were eligible.

Participants were assigned to CGM (wCGM) or non-CGM (xCGM) cohorts based on claims evidence and directly matched on age, sex, insurance type, and diabetes type. Individuals receiving SGLT2 inhibitors or GLP-1 receptor agonists were excluded to reduce confounding. Outcomes included total medical costs, ED and IP days, ED/IP encounters related to hypoglycemia or DKA, and the likelihood of achieving HbA1c less than 9%, using CPT coding to infer glycemic control.

Findings

Among the matched cohorts (469,370 individuals per group), researchers found that CGM use was associated with a 19.8% reduction in total medical costs over 12 months. CGM users also experienced fewer ED and IP days, translating to a 23% reduction in acute care utilization compared with nonusers.

The proportion of individuals with at least one ED or IP encounter related to hypoglycemia (0.89% vs 0.93%), DKA (3.52% vs 4.44%), or both (4.44% vs 5.42%) was significantly lower in the CGM group (all P <.001). CGM users had 19% higher odds of achieving HbA1c less than 9% than nonusers (odds ratio, 1.19; P <.001), a threshold relevant to quality metrics used by payers and accrediting organizations, according to the study.

"Ensuring that eligible individuals are not only prescribed CGM but are supported in sustained use may also contribute to improved performance on quality measures such as STAR Ratings and NCQA Health Plan Ratings, which influence reimbursement and plan growth, particularly within Medicare Advantage populations," the investigators observed.

Among the study's limitations, the authors acknowleged several inherent to claims-based analyses. Laboratory HbA1c values were unavailable, requiring reliance on billing codes rather than continuous measures of glycemic change. The dataset lacked granular socioeconomic data and information on CGM adherence, duration of use, or patient engagement with CGM data. Exclusion of patients using newer glucose-lowering agents may limit generalizability, and findings apply specifically to individuals treated with prandial insulin.

Authors' Comments

"Despite the demonstrated benefits of CGM, adoption remains inconsistent. While most individuals who meet clinical criteria have some level of insurance coverage, barriers such as prior authorization requirements, provider hesitation, perceived device complexity, and out-of-pocket costs continue to limit adoption," Hirsch et al wrote. "In addition, disparities in CGM use across racial, ethnic, and socioeconomic lines raise concerns about equitable access."

The very large untreated segment of eligible individuals in the study "represents an opportunity to improve outcomes and reduce avoidable health care costs." They suggest that provider education, streamlined prescribing, and patient support may be necessary to translate CGM eligibility into sustained use.

"Future research should further evaluate longitudinal outcomes and the impact of CGM duration, adherence, and integration with emerging therapies to better understand how sustained use influences clinical and economic outcomes across diverse populations," they concluded.

References

1. Dennis C, Allaire JC, Bouhairie VE, Hirsch IB. The impact of continuous glucose monitoring use versus nonuse on clinical and economic outcomes in individuals using rapid- and short-acting insulin: A retrospective analysis. Diabetes Technol Ther. Published online December 3, 2025. doi: 10.1177/15209156251403569

2. National Diabetes Statistics Report. Centers for Disease Control and Prevention. Updated May 15, 2024. Accessed December 15, 2025. ww.cdc.gov/diabetes/php/data-research/index.html

3. Fang M, Wang D, Coresh J, Selvin E. Trends in diabetes treatment and control in U.S. adults, 1999–2018. N Engl J Med. 2021;384(23):2219–2228. doi: 10.1056/NEJMsa2032271

4. Mata-Cases M, Rodríguez-Sánchez B, Mauricio D, et al. The association between poor glycemic control and health care costs in people with diabetes: A population-based study. Diabetes Care. 2020;43(4):751–758. doi: 10.2337/dc19-0573

5. Hankosky ER, Schapiro D, Gunn KB, et al. Gaps remain for achieving HbA1c targets for people with type 1 or type 2 diabetes using insulin: Results from NHANES 2009-2020. Diabetes Ther. 2023;14(6):967–975. doi: 10.1007/s13300-023-01399-0

6. Parker ED, Lin J, Mahoney T, et al. Economic costs of diabetes in the U.S. in 2022. Diabetes Care. 2024;47(1):26–43. doi: 10.2337/dci23-0085

7. American Diabetes Association. 7. Diabetes technology: Standards of medical care in diabetes—2025. Diabetes Care 2025;48(Supplement_1):S146–S166. doi: 10.2337/dc25-S007

8. Grunberger G, Sherr J, Allende M, et al. American Association of Clinical Endocrinology Clinical Practice Guideline. The use of advanced technology in the management of persons with diabetes mellitus. Endocr Pract. 2021;27(6):505–537. doi: 10.1016/j.eprac.2021.04.008