Continuous glucose monitoring in type 2 diabetes: from exception to necessity

Abstract

For years, continuous glucose monitoring (CGM) in type 2 diabetes mellitus (T2DM) was reserved for those using insulin in intensive regimens. That criterion is no longer sufficient: the American Diabetes Association's 2026 Standards of Care expanded the indication to all individuals with T2DM receiving insulin, regardless of the regimen, and also to those treating their disease with other glucose-lowering drugs without achieving metabolic control. The question is no longer whether CGM is appropriate in T2DM; today, the debate centers on who should start first and with what modality.

Why and in whom? An analysis of NHANES 2009-2020 found that only 16% of people with T2DM on basal insulin and 12% of those using multiple daily injections achieve their individualized glycemic target. In that same group, a Canadian registry of more than 200,000 people associated the use of CGM with a greater likelihood of therapeutic progress compared to self-monitoring alone. The gap that remained for those combining basal insulin with modern non-insulin therapies is beginning to be filled by the FreeDM2 trial: in that population, it showed a reduction in HbA1c of 0.6 points at 4 months and an increase in time in range to nearly 2.5 hours daily compared to capillary blood glucose self-monitoring. In people not on insulin, the indication still relies on a newer and smaller body of evidence.

How is it used? It is useful to distinguish between two approaches depending on the stage of the disease. In recent diagnosis and in stable type 2 diabetes without insulin, intermittent use for one to two weeks, repeated every three or four months, is sufficient to map the glycemic profile, reinforce adherence, and adjust medications. With basal insulin or multiple regimens, continuous access becomes the preferred modality, as evaluated in FreeDM2. In advanced disease or in frail patients, continuous use prioritizes avoiding hypoglycemia over fine-tuning the dose.

The FreeDM2 results were presented at ATTD 2026 and are still awaiting publication with full peer review, a caveat that should be maintained when citing them. The fundamental shift, however, is clear: continuous glucose monitoring (CGM) in type 2 diabetes is no longer an exception reserved for complex cases and is now being discussed as part of routine management, at the time and with the modality that each stage of the disease requires.