We studied 5-yr T1D risk associations using a series of risk factors in an autoantibody positive population of 6,020 in the TrialNet Pathway to Prevention study (PTP) study. We used data from 25 subgroups developed from 5 AUC glucose (<115;115-<130;130-<145;145-<160; ≥160 mg/dl) and 5 AUC C-peptide (<3.5;3.5-<5.0;5.0-<6.5;6.50-<8.0; ≥8.0 ng/ml) categories from baseline OGTT data. Subgroup boundaries were set to provide quantitative power for proper statistical analysis (range: 138 to 487) . We assessed 5-yr T1D risk associations with risk factors among the 25 subgroups using correlation coefficients and linear regression analysis (slope: 5-yr risk/risk factor prevalence) . The table shows the strongest correlation of 5-yr T1D risk with IA-2A (r=0.96) . This was consistent in split sample analyses, as were the linear regression indices (Sample 1 vs. Sample 2: r=0.96 vs. 0.93; intercept=-0.186 vs. -0.228; slope=0.014 vs. 0.015) . Using the regression indices for a cross-sample validation (i.e., predicting 5-yr risk for one sample using its IA-2A prevalence and the other sample's regression indices) , the predicted/actual 5-yr risk was 0.27/0.26 for Sample 1 and 0.27/0.23 for Sample 2.
In summary, in PTP subgroups, 5-yr T1D risk correlated strongly with IA-2A. Further, regression indices predicted 5-yr T1D risk in cross-sample validation, suggesting a tight linkage between active β-cell decline and IA-2A.
H.M.Ismail: n/a. D.D.Cuthbertson: None. M.A.Atkinson: None. M.J.Redondo: Advisory Panel; Provention Bio, Inc. J.Sosenko: None. Type 1 diabetes trialnet: n/a.