J Clin Endocrinol Metab. 2022 May 7:dgac285. doi: 10.1210/clinem/dgac285. Online ahead of print.
ABSTRACT
CONTEXT: Decreased first-phase insulin response (FPIR) during intravenous glucose tolerance testing (IVGTT) is an early indicator of β-cell dysfunction and predictor of type 1 diabetes (T1D).
OBJECTIVE: Assess whether oral glucose tolerance test (OGTT) measures could serve as FPIR alternatives in their ability to predict T1D in autoantibody positive (Aab+) subjects.
DESIGN: OGTT and IVGTT were performed within 30 days of each other. Eleven OGTT variables were evaluated for: 1) correlation with FPIR, and 2) T1D prediction.
SETTING: Type 1 Diabetes TrialNet “Oral Insulin for Prevention of Diabetes in Relatives at Risk for T1D” (TN-07) and Diabetes Prevention Trial-Type 1 Diabetes (DPT-1) studies clinical sites.
PATIENTS: TN-07 (n=292; age 9.4±6.1 years) and DPT-1 (n=194; age 15.1±10.0 years) Aab+ relatives of T1D individuals.
MAIN OUTCOME MEASURES: 1) Correlation coefficients of OGTT-measures with FPIR, and 2) T1D prediction at 2-years using area under receiver operating characteristic (ROCAUC) curves.
RESULTS: Index60 showed the strongest correlation in DPT-1 (r=-0.562) but was weaker in TN-07 (r=-0.378). C-peptide index consistently showed good correlation with FPIR across studies (TN-07, r=0.583; DPT-1, r=0.544; p<0.0001). Index60 and C-peptide index had the highest ROCAUCs for T1D prediction (0.778 vs. 0.717 in TN-07; 0.763 vs. 0.721 in DPT-1, respectively; p=NS), followed by FPIR (0.707 in TN-07; 0.628 in DPT-1).
CONCLUSIONS: C-peptide index was the strongest measure to correlate with FPIR in both studies. Index60 and C-peptide index had the highest predictive accuracy for T1D and were comparable. OGTTs could be considered instead of IVGTTs for subject stratification in T1D prevention trials.
PMID:35524749 | DOI:10.1210/clinem/dgac285
