Continuous Glucose Monitoring Beneficial in Type 2 Diabetes Not Treated With Insulin

— Users had a lower HbA1c level and spent 5 more hours in target range

Use of a continuous glucose monitor (CGM) reduced HbA1c levels in adults with type 2 diabetes not treated with insulin, the randomized CONNECT trial showed.

Among 283 patients at primary care practices, mean HbA1c levels decreased from 8.8% to 7.2% in the CGM group and from 8.7% to 8.0% in the routine-care group by week 26 (adjusted mean difference -0.9 percentage points, 95% CI -1.1 to -0.6, P<0.001), reported Roy W. Beck, MD, PhD, of the Jaeb Center for Health Research in Tampa, Florida, and colleagues.

Time spent in the target glucose range (70-180 mg/dL) was 21 percentage points higher with CGM than with routine care (P<0.001), equivalent to about 5 more hours per day in the target range.

"Results for glycated hemoglobin and time-in-range outcomes were similar across a wide range of participant characteristics," the authors wrote in the New England Journal of Medicineopens in a new tab or window.

Several previous trials have shown that CGM is beneficial for patients with type 1 diabetes and insulin-treated type 2 diabetes, but evidence has been limited in those with non-insulin-treated type 2 diabetes.

"The 2026 American Diabetes Association Standards of Careopens in a new tab or window cites level A evidence (clear evidence from well-conducted, generalizable, randomized, controlled trials) to recommend the use of CGM by persons with diabetes receiving insulin therapy but cites only level C evidence (supportive evidence from poorly controlled or uncontrolled studies) for the treatment of persons with non-insulin-treated diabetes," Beck and team noted.

Therapies such as GLP-1 receptor agonists and SGLT2 inhibitors have also helped patients with type 2 diabetes achieve a target HbA1c below 7%, but whether non-insulin-treated patients with elevated HbA1c levels would benefit from CGM was unclear.

The CONNECT trialopens in a new tab or window was conducted at 22 U.S. primary care practices to maximize the generalizability of the results, as most patients receive type 2 diabetes care in primary care settings.

Patients ranged in age from 21 to 84 years (mean age 59-60), had type 2 diabetes for at least 6 months, and had a baseline HbA1c level of at least 7.5%. Eligible participants had not used real-time CGM in the preceding 6 months or insulin in the preceding 12 months, and had stable non-insulin glucose-lowering or weight-loss medications for the previous month.

At baseline, GLP-1 receptor agonists were used by 40% of participants, SGLT2 inhibitors by 37%, and both classes by 18%.

During the trial, insulin or non-insulin glucose-lowering medications were added for 31% of participants in the CGM group and 17% in the routine-care group. Because medications were added for only a minority of participants, Beck and colleagues pointed out that "the improvement observed with CGM cannot be explained by medication changes alone but may have been due to modifications in behavioral habits that could affect glucose levels."

Time spent in hypoglycemia (below 70 mg/dL) and severe hypoglycemia (below 54 mg/dL) was 0.20 and 0.17 percentage points lower in the CGM group, respectively. Time spent in severe hyperglycemia (above 250 mg/dL) was 15 percentage points lower in the CGM group.

No cases of severe hypoglycemia or hyperglycemia-related serious adverse events were observed. Across the trial, 33 and 24 adverse events occurred in the CGM group and the routine-care group, respectively; only three sensor-related adverse events were reported in the CGM group (two for bleeding at the insertion site and one upon sensor removal).

CGM adherence during the study was high, with a median use of 97% of the time. "Provision of sensors to the trial participants and the visit frequency might have affected the high percentage of CGM use that was observed, and adherence and glycemic benefit might be lower with real-world use," Beck and team acknowledged.

A 26-week extension phase is underway to assess sustained CGM use and the durability of its effects.