Free-living glucose profiles obtained using continuous glucose monitoring (CGM) may reflect differences in insulin resistance and insulin secretion in individuals with obesity. In Diabetes Care, an observational study evaluated the relationship between CGM-derived glucose metrics and validated indices of insulin resistance and insulin secretion in adults with obesity, with and without type 2 diabetes mellitus (T2DM).

The study included 37 adults with obesity, comprising 17 individuals with obesity and T2DM (OB[+T2DM]) and 20 individuals with obesity without T2DM (OB[−T2DM]). All participants wore a CGM device and underwent a 2-hour oral glucose tolerance test (OGTT). Of these, 27 participants also completed a two-step hyperglycemic–euglycemic clamp. CGM metrics were calculated and correlated with indices of insulin resistance and insulin secretion derived from OGTT and clamp testing.

CGM metrics, including mean glucose and glycemic variability indices, were higher in the OB(+T2DM) group than in the OB(−T2DM) group (P < 0.001). When all participants were analyzed together, CGM mean inversely correlated with insulin resistance indices, including the OGTT-derived insulin sensitivity index and glucose infusion rate (GIR) from the clamp (GIR: r = −0.82; P < 0.001). Similar inverse correlations were observed when groups were analyzed separately (P < 0.01).

CGM mean negatively correlated with insulin secretion indices only when the two groups were analyzed together (P < 0.05). In group-specific analyses, CGM mean positively correlated with insulin levels measured during the OGTT and the hyperglycemic step of the clamp in the OB(−T2DM) group, but not in the OB(+T2DM) group.

The analysis showed that CGM metrics, particularly CGM mean, were associated with measures of insulin resistance in adults with obesity.