The following is a summary of “OGTT Metrics Surpass Continuous Glucose Monitoring Data for T1D Prediction in Multiple-Autoantibody–Positive Individuals,” published in the January 2024 issue of Endocrinology by Ylescupidez, et al.

The effectiveness of continuous glucose monitoring (CGM) in monitoring individuals positive for autoantibodies (AAB) in clinical trials assessing the progression of type 1 diabetes (T1D) remains uncertain. For a study, researchers sought to compare the predictive value of CGM with oral glucose tolerance test (OGTT)-based metrics in forecasting the onset of T1D.

OGTT and CGM data from multiple AAB relatives were analyzed for their association with T1D diagnosis. Participants included individuals positive for multiple AABs in a TrialNet Pathway to Prevention (TN01) CGM ancillary study (n = 93). The intervention involved CGM monitoring for one week at baseline, six months, and twelve months. Receiver operating characteristic (ROC) curves of CGM and OGTT metrics for predicting T1D were assessed.

While five out of seven OGTT metrics and 29 out of 48 CGM metrics differed between individuals who subsequently developed T1D and those who did not, HbA1c did not show a significant difference. ROC area under the curve (AUC) of individual CGM values ranged from 50% to 69%, improving when adjusted for age and AABs. However, OGTT-derived metrics, particularly Index60 and DPTRS (Diabetes Prevention Trial-Type 1 Risk Score), exhibited higher discriminative ability, with AUCs around 80%. Compared to adjusted multivariable models using CGM data, OGTT-derived variables showed higher discriminative ability with similar negative predictive value but higher positive predictive value.

While CGM measurements every six months in multiple-AAB-positive individuals can predict subsequent T1D to some extent, OGTT-derived variables demonstrate superior predictive ability. While CGM may offer feasibility advantages and utility in certain contexts, the findings suggest insufficient evidence to replace OGTT measures with CGM in clinical trial settings.

Reference: academic.oup.com/jcem/article-abstract/109/1/57/7241780