Interindividual differences in hemoglobin glycation limit the accuracy of HbA1c as a universal glycemic marker. A study presented at the 51st Annual Conference of the International Society for Pediatric and Adolescent Diabetes (ISPAD) evaluated a CGM-independent adjusted HbA1c (aA1c) derived from the GA to HbA1c ratio as an alternative to the glucose management indicator (GMI).

The analysis included 803 individuals with T1DM with simultaneous measurement of HbA1c and GA. A GA-derived HbA1c served as the dependent variable. Multiple regression modeling incorporated age, body mass index percentile, HbA1c, GA/HbA1c ratio, and insulin dose (unit/kg). The predicted value from this model defined aA1c.

The resulting formulas were aA1c-NGSP = 0.71 × HbA1c + 1.96 × (GA/HbA1c) − 3.46 and aA1c-IFCC = 0.914 × HbA1c + 8.938 × (GA/HbA1c) − 54.3. Both estimates demonstrated strong correlation with GA-derived HbA1c (r = 0.998 for NGSP and r = 0.996 for IFCC; p < 0.0001).

These findings indicate that aA1c reliably adjusts for individual glycation variability without CGM and may support personalized assessment of glycation-related risk in T1DM.