Comment on Redondo et al. Racial/Ethnic Minority Youth With Recent-Onset Type 1 Diabetes Have Poor Prognostic Factors. Diabetes Care 2018;41:1017–1024

I read with interest an article by Redondo et al. (1) that reported a significantly lower rate of partial clinical remission in African Americans (AAs) compared with non-Hispanic whites (NHWs) in the first 3 years of diagnosis with type 1 diabetes and no differences in the lipid profile between the groups.

This interesting report may represent a key drawback of the gold-standard test for partial clinical remission, the insulin dose–adjusted hemoglobin A_1c (IDAA1c) of ≤9.0%. The IDAA1c has been criticized for its shortcomings, including the underestimation of the prevalence of partial clinical remission in older, obese European girls who are more insulin resistant (2), as it cannot discriminate between insulin sensitivity and insulin secretion (2). The IDAA1c, based on data from European and Japanese youth with type 1 diabetes (3), has not been validated in ethnic minorities in the U.S. who possess unique characteristics that differ from the European and Japanese cohorts used to derive the IDAA1c formula. Compared with their European and Japanese counterparts, U.S. minority youth with type 1 diabetes have higher BMI values (1,3) and a 0.4% higher mean HbA_1c value for the same mean glucose concentration (4).

Therefore, from the outset, the use of IDDA1c of ≤9.0% to define partial clinical remission in U.S. ethnic minorities will grossly underestimate their partial clinical remission frequency through the synergistic effect of elevated BMI and elevated HbA_1c from abnormal glycation at a greater magnitude than the reported underestimation of partial clinical remission in obese European girls (2).

Equally, reports show that the total daily dose of insulin, another factor that underpins IDDA1c value, is largely dependent on factors that cannot be detected by the IDDA1c, such as insulin sensitivity, patient’s compliance, and the accuracy of reported insulin doses (2).

It is particularly interesting that despite the reported 3-year duration of poor glycemic control in AAs, there was no significant difference in the occurrence of dyslipidemia, the primary objective marker of cardiovascular risk, between AAs and NHWs, suggesting that despite the higher reported HbA_1c in the AAs, these youth largely had similar mean glucose concentration to the NHWs (4). This is supported by extensive reports that ethnic disparities in glycation lead to higher HbA_1c in AAs compared with NHWs (5).

Therefore, the conclusion that “AA participants, compared with NHW, were less likely to be in partial remission or ‘honeymoon,’ as defined by IDAA1c ≤9.0%, within the initial 3 years postdiagnosis” (1) is misleading given the above unique characteristics of AAs and the failure of IDDA1c to capture these population-specific attributes.

The presence of population-specific characteristics in U.S. minority youth with type 1 diabetes calls for a dedicated population-specific definition of partial clinical remission that takes into account their increased adiposity, increased insulin resistance, and elevated glycation, all leading to higher HbA_1c values and total daily dose of insulin, which easily raise the IDDA1c to >9.0%, resulting in gross underestimation of partial clinical remission in this population.

The American Diabetes Association should fund research studies aimed at providing an accurate definition of partial clinical remission in all U.S. children rather than relying on European and Japanese models that do not accurately reflect the ethnic diversity of the U.S.