Suzan Wopereis1, Regina JM Kamstra1, Sanne A Haanstra1, Dagmar J Smid1, Tim J van den Broek1, Willem J. van den Brink1
1Netherlands Organization for Applied Scientific Research (TNO), the Netherlands
Background: It becomes more evident that different tissue-specific insulin resistant subtypes exist in persons with type 2 (pre)diabetes (T2D) that may require a personalised treatment strategy. Diabetyping, the methodology to subtype persons with T2D is based on an extended oral glucose tolerance test (OGTT), which is invasive and often causing nausea. Therefore, we aim to develop minimally invasive alternatives of diabetyping.
Methods: In this observational study, 17 out of the expected 57 people with overweight/(pre)T2D used a continuous glucose monitor (CGM) for 20 days and underwent three mornings of measurements: one traditional OGTT (sugar water solution drink) and two times a modified OGTT in which a standardized snack (two pieces of a gingerbread based snack, ‘Snelle Jelle’, naturel 65 gram) after an overnight fast were consumed. Continuously measured subcutaneous glucose, as well as glucose, insulin, and C-peptide via venous as well as via capillary at home sampling was collected and agreement analyses were performed to compare the different measurement methods within the traditional and modified OGTT.
Results: Preliminary results of glucose, insulin, and C-peptide venous and CGM glucose values of the traditional and modified OGTT all showed a large deviation for all timepoints (MARD > 10%). This also resulted in a significantly poor agreement between CGM and venous diabetyping during the traditional OGTT (κ=0.206, z=2, p=0.046) and modified OGTT (k=0.325, z=3.06, p=0.002). However, a significant moderate agreement between the traditional OGTT and the modified OGTT with venous sampling was found (κ=0.432, z=3.95, p=7.89e-05).
Discussion/Conclusion: Based on preliminary results the modified OGTT with venous sampling shows potential as an alternative to the traditional OGTT. With the use of the modified OGTT complaints such as nausea, caused by the sugary drink, could be prevented. Current diabetyping cut-off values, based on traditional OGTT venous measurements, may require adaptation for CGM use. Further analysis on multiday CGM data for diabetyping as minimally invasive alternative are planned.