Summary
Continuous glucose monitoring (CGM) is recommended for type 1 and type 2 diabetes patients, particularly those using insulin. CGM provides real-time glucose data, helping patients and clinicians adjust treatment plans, improve glycemic control, and reduce the risk of hypoglycemia and hyperglycemia. While generally beneficial, skin reactions and potential sensor interference from certain medications should be considered.
Editor: Deborah Sesok-Pizzini, MD, MBA, adjunct professor, Department of Clinical Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
Analysis of the use of continuous glucose monitoring
March 2026—Since publication of the Diabetes Control and Complications Trial in 1993, both hemoglobin A1C (HbA1C) and fingerstick testing with a blood glucose meter have been recommended for glucose monitoring. Continuous glucose monitoring (CGM) may be used to complement HBA1C and replace fingerstick testing. Although CGM is primarily used to manage patients with type 1 diabetes, randomized clinical trials report a benefit for patients with type 2 diabetes treated with a regimen of multiple daily doses of insulin. A meta-analysis of 12 randomized clinical trials that compared CGM to the use of a blood glucose monitor across the spectrum of type 2 diabetes showed a consistency of benefits for insulin, noninsulin, and mixed treatments. Furthermore, the American Diabetes Association (ADA) recommends CGM for people with type 1 or type 2 diabetes using any type of insulin regimen and consideration of CGM for those with noninsulin-treated type 2 diabetes. The association also recommends considering CGM for outpatients with type 2 diabetes who take sulfonylureas and are at increased risk of hypoglycemia. The authors of this article focused on the use of CGM in type 2 diabetes, with the intent of educating primary care clinicians who prescribe and manage CGM in the diabetic population. The authors reviewed evidence supporting the effectiveness of CGM, as well as CGM self-management tools, data reports, adverse effects, and contraindications. They stated that CGM monitoring is beneficial because it shows people if their readings are high or low before meals, allowing them to adjust mealtime insulin doses, and it shows them the effects of food choices on post-meal glucose, as well as the effects of exercise. The authors emphasized that the association between self-management behaviors and reduced hyperglycemia is evident even in the first week after initiating CGM. Clinicians also benefit from CGM because they can review patient laboratory data in standardized reports, recommended by the ADA, that aggregate data from over the prior 14 days into the single-page, three-panel Ambulatory Glucose Profile (AGP). These data complement HbA1C, which reflects mean glycemia levels over the preceding two to three months but does not provide information on when hypoglycemia or hyperglycemia is occurring. The AGP report also includes a glucose-management indicator, which transforms CGM-measured mean glucose into HbA1C units. The report too can be used for health care system and population-level reporting of the quality of glycemic management. However, skin reactions can limit the use of CGM in some people. These reactions can often be managed using barrier adhesives and films, as well as other strategies. The authors noted that acetaminophen, high-dose vitamin C, and hydroxyurea can also interfere with glucose monitoring on some sensors, so manufacturer guidance should be followed. The authors concluded that CGM monitoring may help guide dietary choices, exercise routines, and medication use by showing patterns in users’ glucose profiles. Moreover, CGM can decrease hyperglycemia and hypoglycemia and thereby improve the safety and efficacy of diabetes management.
Bergenstal RM, Martens TW, Beck RW. Continuous glucose monitoring. JAMA. 2025. doi.org/10.1001/jama.2025.19197
Correspondence: Dr. Roy W. Beck at [email protected]