Adding Continuous Glucose Monitoring to Semaglutide Nearly Doubles the Chance of Hitting Blood Sugar Targets | Research

The takeaway

Patients using both continuous glucose monitoring and semaglutide saw an additional 0.55% HbA1c reduction compared to semaglutide alone, with the proportion reaching ADA targets nearly doubling.

-0.55% additional HbA1c reduction
Adding continuous glucose monitoring to semaglutide provided a clinically meaningful extra HbA1c benefit (p < 0.0001) beyond semaglutide alone in over 21,000 patients.

What the researchers found

Among 21,247 adults with type 2 diabetes using semaglutide, the 2,759 who also used CGM achieved significantly greater HbA1c improvements than the 18,488 using semaglutide alone (difference-in-differences: -0.55%, 95% CI: -0.64% to -0.47%, p < 0.0001).

Among CGM users, the proportion meeting the ADA target of HbA1c < 7.0% nearly doubled, and the proportion achieving the HEDIS target of HbA1c < 8.0% increased by more than 50%. These results suggest that CGM provides an additive benefit beyond the pharmacological effect of semaglutide alone.

Why it matters

This study provides real-world evidence that combining technology (CGM) with pharmacotherapy (semaglutide) produces better diabetes outcomes than medication alone. As both CGM and GLP-1 agonists become more widely prescribed, understanding their synergistic benefits can help clinicians optimize treatment and support expanded insurance coverage for CGM in type 2 diabetes patients.

How the study worked

Retrospective analysis of US healthcare administrative claims from the Optum Clinformatics database. Adults with type 2 diabetes using semaglutide between January 2019 and September 2022 were identified. The CGM cohort had at least one CGM-related claim; the control group used semaglutide without CGM. At least one baseline and one follow-up HbA1c lab value were required. Difference-in-differences analysis compared HbA1c changes between groups.

What this study cannot tell us

This is a retrospective observational study using claims data, so it cannot prove causation. CGM users may be more health-engaged or have different baseline characteristics than non-users, introducing selection bias. The study could not control for differences in diet, exercise, or medication adherence between groups. Claims data may not capture all CGM use (e.g., over-the-counter devices). Semaglutide dose and formulation (oral vs. injectable) were not differentiated.

How to read the evidence

This is a large retrospective claims-based analysis of over 21,000 patients. The sample size provides strong statistical power, and the difference-in-differences approach partially controls for confounders. However, the observational design with potential selection bias limits causal inference compared to a randomized trial.

When this study was published

Published in 2025 with data through September 2022, this is current research addressing a timely question about combining the two fastest-growing categories in diabetes management — GLP-1 drugs and CGM technology.

The bigger picture

CGM has traditionally been associated with type 1 diabetes management, but its use in type 2 diabetes is growing rapidly. This study adds to the evidence that CGM benefits extend beyond insulin-dependent patients. When patients can see in real-time how their meals, activity, and medication affect blood sugar, they make better behavioral choices that complement the pharmacological effects of GLP-1 drugs. This tech-plus-drug combination could become the standard of care for type 2 diabetes management.

Questions still open

Would a randomized trial of CGM added to semaglutide show the same magnitude of additional HbA1c benefit?
Is the CGM benefit driven by behavior change (better food/activity choices) or by more optimized medication dosing guided by glucose data?
Would the additive benefit of CGM be similar with other GLP-1 drugs like tirzepatide or dulaglutide?

Common questions

Why would wearing a glucose monitor make semaglutide work better?

Semaglutide works pharmacologically to lower blood sugar, but a continuous glucose monitor adds a behavioral component — patients can see in real-time how food, activity, and timing affect their levels. This feedback likely motivates better food choices, more consistent medication timing, and more physical activity, which combined with the drug's effects leads to better blood sugar control.

Should everyone on semaglutide get a CGM?

This study suggests it could help, especially for patients not meeting their HbA1c targets on semaglutide alone. However, CGM adds cost and requires wearing a sensor. Insurance coverage for CGM in type 2 diabetes varies. Patients should discuss with their doctor whether the potential benefit justifies the cost and inconvenience for their individual situation.

Read the original research

Combined effect of continuous glucose monitoring and semaglutide: analysis of administrative claims.

The American journal of managed care, 31(4), 183-188

View on PubMed ↗Publisher’s paper ↗

Citation

Nemlekar, Poorva M; Hannah, Katia L; Green, Courtney R; Grace, Thomas; Lynch, Peter M; Castle, Jessica R; Norman, Gregory J. (2025). Combined effect of continuous glucose monitoring and semaglutide: analysis of administrative claims.. The American journal of managed care, 31(4), 183-188. https://doi.org/10.37765/ajmc.2025.89719