Early Hyperglycemia Detected by Continuous Glucose Monitoring in Children at Risk for Type 1 Diabetes

OBJECTIVE: We explore continuous glucose monitoring (CGM) as a new approach to defining early hyperglycemia and diagnosing type 1 diabetes in children with positive islet autoantibodies (Ab+). RESEARCH DESIGN AND METHODS: Fourteen Ab+ children, free of signs or symptoms of diabetes, and nine antibody-negative (Ab-) subjects, followed by the Diabetes Autoimmunity Study in the Young, were asked to wear a Dexcom SEVEN CGM. RESULTS: The Ab+ subjects showed more hyperglycemia, with 18% time spent above 140 mg/dL, compared with 9% in Ab- subjects (P = 0.04). Their average maximum daytime glucose value was higher, and they had increased glycemic variability. The mean HbA1c in the Ab+ subjects was 5.5% (37 mmol/mol). Among Ab+ subjects, ≥18-20% CGM time spent above 140 mg/dL seems to predict progression to diabetes. CONCLUSIONS: CGM can detect early hyperglycemia in Ab+ children who are at high risk for progression to diabetes. Proposed CGM predictors of progression to diabetes require further validation.