A Comparison of HbA1c and Index 60 Thresholds for Identifying Autoantibody Positive Individuals at High Risk for Type 1 Diabetes (T1D)

Current ADA standards include HbA1c values 5.7%-6.4% as an indicator of prediabetes. However, there is little information with regard to HbA1c as a specific predictor of T1D. We thus compared HbA1c with Index 60, a T1D marker, for identifying individuals at high risk for T1D. Index 60 was derived from a proportional hazards regression model for T1D that included log fasting C-peptide, 60-minute glucose, and 60-minute C-peptide. Diabetes Prevention Trial-type 1 participants with Index 60 In conclusion, Index 60≥2.00 was superior to HbA1c ≥6.0 at identifying individuals at high risk for T1D. Moreover, those with incident HbA1c ≥6.0 were much older with higher C-peptide levels, suggesting heterogeneity. These findings add support for including C-peptide together with glucose in developing predictors and pre-diagnostic endpoints that are specific for T1D. Disclosure L.M. Jacobsen: None. H.M. Ismail: None. M.A. Clements: Speaker9s Bureau; Self; Medtronic. Advisory Panel; Self; Glooko, Inc.. D. Schatz: None. J. Sosenko: None.