Abstract
The ODI is a measure of β-cell function accounting for insulin sensitivity. ODI has primarily been studied in adults and shown to be inversely predictive of type 2 diabetes (T2D) ; however, little is known about ODI's prediction of T1D. We thus used data from Ab+ Trialnet Pathway to Prevention (PTP) and Diabetes Prevention Trial Type 1 (DPT-1) cohorts (relatives of T1D patients) to study this. Data were analyzed from 33PTP participants: age (mean±SD) 15.8±12.1 yrs; BMI 21.1±13.1 kg/m2; 50.1% female, and 2from DPT-1: age 14.8±10.0 yrs; BMI 21.8±6.1 kg/m2; 51.2% female. Insulin measures at baseline included insulin sensitivity [ (1/Fasting Insulin) ; 1/FI) ], β-cell function [C-peptide index: (30 min C-pep-0 min C-pep) / (30 min glucose-0 min glucose) ], and ODI [ (1/FI) x (C-peptide Index) ]. Spearman correlations of C-peptide Index vs. 1/FI were r=-0.47 (p<0.001) in PTP, and r=-0.22 (p=0.001) in DPT-1. The figure shows cumulative incidence curves according to ODI quartiles (Q) for progression to T1D in both PTP and DPT-1. The diagnosis of T1D was inversely related to ODI, with Q4 vs. Q1 hazard ratios and 95% CIs of [0.13 (0.10, 0.16) , p=0.006] for PTP and of [0.13 (0.06, 0.29) , p=0.002] for DPT-1. In conclusion, ODI is inversely predictive of T1D among Ab+ individuals. Thus, as with predicting T2D, insulin sensitivity should be taken into account when β-cell function is used to predict T1D in Ab+ populations.
