Initial Presentation of Type 2 Diabetes in Adolescents Predicts Durability of Successful Treatment with Metformin Monotherapy: Insights from the Pediatric Diabetes Consortium T2D Registry

Background/aims: Many adolescents with type 2 diabetes (T2D) have rapid deterioration of glycemic control on metformin monotherapy within 2 years of diagnosis.

Methods: Enrollment data from the Pediatric Diabetes Consortium T2D Registry were used to categorize 276 youth with a T2D duration ≥2 years into two groups: (1) participants with HbA1c <7.5% on metformin monotherapy (group 1, n = 75) and (2) participants treated with insulin ± metformin (group 2, n = 201). The characteristics of the groups were compared.

Results: At enrollment, groups 1 and 2 did not differ in age (16.2 vs. 16.8 years) or BMI percentile (99 vs. 98%); group 2 had higher HbA1c (9.9% [85 mmol/mol] vs. 5.9% [41 mmol/mol], p < 0.001). Lower HbA1c and metformin monotherapy at diagnosis were associated with a greater likelihood of adequate control with metformin alone (p < 0.001). In multivariable analysis, HbA1c at diagnosis (p = 0.001) and diabetes duration (p = 0.009) were associated with adequate control on metformin. The HbA1c trajectory after diagnosis was worse in group 2.

Conclusion: Durable metabolic control of T2D with metformin monotherapy is most likely in youth presenting with lower HbA1c and with shorter diabetes duration, independent of age, race-ethnicity, and BMI. Elevated HbA1c levels in those on insulin therapy highlight the importance of early diagnosis and a better understanding of glycemic control barriers.