The potential of glucose management indicator for the estimation of glucose disposal rate in people with type 1 diabetes

Background and aims: Insulin resistance is a growing feature in type 1 diabetes (T1D). It can be quantified by calculating the estimated glucose disposal rate (eGDR) with the Epstein's formula, which includes laboratory-measured glycated hemoglobin (HbA1c). We aimed the current research to assess the agreement between the conventional eGDR formula and an alternative one (eGDR-GMI) incorporating the glucose management indicator (GMI) derived from continuous glucose monitoring (CGM). We also explored the relationship between eGDR-GMI, cardiovascular risk factors, and the prevalence of diabetes-related complications. Methods and results: We designed a cross-sectional study that included adults with T1D. eGDRGMI and eGDR (mg/kg/min) were calculated using GMI or HbA1c, waist circumference, and hypertensive state. Clinical data were collected from electronic medical records. The analyses encompassed 158 participants with a mean age of 39 f 13 years. The BlandAltman analysis showed a good agreement between eGDR-GMI and eGDR. When we divided participants in eGDR-GMI tertiles we found a higher prevalence of diabetes-related complications and a less favorable metabolic profile in the lowest eGDR-GMI tertile. The relative risk of retinopathy, nephropathy, and neuropathy significantly increased by approximately 1 unit with each decrease in eGDR-GMI, regardless of age, sex, disease duration, lipids, and smoking habit. Conclusions: eGDR-GMI represents a valid and robust alternative to the eGDR to assess insulin resistance in T1D. Low eGDR-GMI is associated with diabetes complications and a less favorable metabolic profile. Incorporating the eGDR-GMI into clinical practice can enhance the characterization of T1D people and allow for a more personalized treatment approach. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).