IDAA1c showed suboptimal performance for identifying partial remission in US youth with type 1 diabetes mellitus (T1DM). A study presented at the 51st Annual Conference of the International Society for Pediatric and Adolescent Diabetes (ISPAD) reported findings from the SEARCH for Diabetes in Youth study comparing IDAA1c with stimulated C-peptide.

The analysis included 420 participants younger than 20 years with T1DM duration of less than 1 year. Participants were grouped by body mass index percentile into normal or underweight (≤85th percentile; n = 299) and overweight or obese (>85th percentile; n = 121). Partial remission was defined as stimulated C-peptide ≥0.91 ng/mL. IDAA1c ≤9 was used as the standard cutoff. Sensitivity, specificity, and receiver operating characteristic area under the curve were calculated.

In the overall cohort, IDAA1c ≤9 showed a sensitivity of 61% and specificity of 79%. In normal or underweight youth, sensitivity was 69% and specificity was 79%, with an area under the curve of 0.80. In overweight or obese youth, sensitivity was 45% and specificity was 81%, with an area under the curve of 0.78. Use of an IDAA1c cutoff of ≤11.6 in the overweight or obese group increased sensitivity to 58% and specificity to 93%.

These results show that IDAA1c performance differed by body mass index group in this US-based cohort. Sensitivity was lower in overweight and obese youth when using the ≤9 cutoff. A higher cutoff improved performance metrics in this group.