Continuous Glucose Monitoring Metrics in Asians Without Diabetes: Differentiating Prediabetes From Normoglycemia

Early detection of dysglycemia is important to delay the progression to diabetes. Continuous glucose monitoring (CGM) may offer advantages over current diagnostic methods for prediabetes. However, reference intervals for CGM metrics among Asians with normoglycemia (NG), and their differences compared with prediabetes, have not been well characterized.

Healthy Asian adults were classified using American Diabetes Association criteria via 75-g oral glucose tolerance test and HbA1c as NG, prediabetes, or diabetes. Participants without diabetes wore a blinded CGM device. Reference intervals (2.5th and 97.5th percentiles) for NG were determined. Continuous glucose monitoring metrics were compared between NG and prediabetes using the two-sample t-test or Mann-Whitney U test as appropriate. The area under the receiver operating characteristic (AUROC) curve and the Youden Index were used to identify optimal diagnostic thresholds for prediabetes.

Of 160 participants, one was diagnosed with diabetes. A total of 151 individuals with adequate CGM data were analyzed, including 27 participants with prediabetes (median age 32 years, BMI 22 kg/m², HbA1c 5.4%, 36 mmol/mol). Reference intervals for NG included: mean glucose (78-106 mg/dL), TIR 70 to 180 mg/dL (69%-100%), TIR 54 to 140 mg/dL (86.4%-100%), TAR >140 mg/dL (0%-9.7%), and standard deviation (10.9-25.6 mg/dL). Among CGM metrics, TAR140 had the highest AUROC at 0.72 and an optimal threshold of 5.6%.

Asians with NG spend most of their time within TIR 54 to 140. TAR140 may be a useful metric for distinguishing prediabetes from NG.