Continuous glucose monitoring (CGM) metrics are increasingly used to assess glycemic control beyond glycated hemoglobin (HbA1c), yet comparative data across commonly used therapies remain limited. A secondary analysis from the Glycemia Reduction Approaches in Diabetes (GRADE) trial, published in Diabetes Care, evaluated CGM-derived metrics across four glucose-lowering medications added to metformin in individuals with type 2 diabetes mellitus (T2DM).

The randomized trial included participants assigned to insulin glargine, glimepiride, liraglutide, or sitagliptin, with follow-up of approximately 5 years. A subset of 1,080 participants underwent a 2-week masked CGM assessment to evaluate time in range (TIR70–180 mg/dL), time below range (TBR<70 mg/dL), glycemic variability (% coefficient of variation [%CV]), and achievement of consensus CGM targets.

Sitagliptin and liraglutide groups showed higher TIR70-180 and lower TBR<70 and %CV compared with other treatments. In contrast, glimepiride was associated with lower TIR, higher glycemic variability, and more hypoglycemic events, including daytime hypoglycemia (P<0.001). Incretin-based therapies were more likely to meet consensus CGM targets, including TIR >70% and minimal hypoglycemia. Across HbA1c strata, mean glucose levels were similar, but %CV and hypoglycemia remained higher with glargine and glimepiride.

These findings indicate that CGM metrics provide additional insights beyond HbA1c and may help differentiate treatment effects in T2DM management.