Exploring Insulin Resistance in Adults With Type 1 Diabetes: The Role of the Estimated Glucose Disposal Rate and the Triglyceride Glucose Index.

Aims: People with type 1 diabetes (T1D) who exhibit insulin resistance present a high cardiovascular risk. Several markers, including the estimated Glucose Disposal Rate (eGDR) and Triglyceride-Glucose (TyG) index, have been developed for measuring insulin resistance. The debate on the most reliable surrogate estimator is still open. The aim was to assess the prevalence of insulin resistance by eGDR and TyG index in adults with T1D, describe the characteristics of the population according to insulin resistance, and investigate the association between these indices and glucose control.

Materials and methods: This study involved adults with T1D of both sexes in stable insulin treatment for at least 6 months, whose data were collected at 1-year follow-up visit. Insulin resistance was based on eGDR < 8 and TyG index ≥ 4.68.

Results: We included 687 adults with a median age of 29.0 years and diabetes duration of 18.0 years. Insulin resistance was found in 25.8% and 39.2% of the population based on the eGDR and TyG index, respectively. Compared with those without insulin resistance, insulin-resistant participants showed poorer glyco-metabolic parameters and required larger daily insulin dose; moreover, people with insulin resistance according to the TyG index needed higher daily insulin doses/kg. At logistic regression, we found significant association between glucose control (HbA1c ≤ 7%) and both eGDR (β = 1.143) and TyG index (β = -1.578).

Conclusions: In adults with T1D, there was a significant prevalence of insulin resistance measured by the eGDR e TyG index, which was effective in identifying individuals who needed higher insulin doses/kg. Both indices correlated with glucose control.