We assessed whether Index60, a composite measure of fasting C-peptide, 60-min C-peptide, and 60-min glucose, could improve the metabolic staging of type 1 diabetes for progression to clinical disease (stage 3) among autoantibody-positive (Ab⁺) individuals with normal 2-h glucose values (<140 mg/dL).

We analyzed 3,058 Type 1 Diabetes TrialNet Pathway to Prevention participants with 2-h glucose <140 mg/dL and Index60 <1.00 values from baseline oral glucose tolerance tests. Characteristics associated with type 1 diabetes (younger age, greater Ab⁺, higher HLA DR3-DQ2/DR4-DQ8 prevalence, and lower C-peptide) were compared among four mutually exclusive groups: top 2-h glucose quartile only (HI-2HGLU), top Index60 quartile only (HI-IND60), both top quartiles (HI-BOTH), and neither top quartile (LO-BOTH). Additionally, within the 2-h glucose distribution of <140 mg/dL and separately within the Index60 <1.00 distribution, comparisons were made between those above or below the medians.

HI-IND60 and HI-BOTH were younger, with greater frequency of more than two Ab⁺, and lower C-peptide levels, than either HI-2HGLU or LO-BOTH (all P < 0.001). The cumulative incidence for stage 3 was greater for HI-IND60 and HI-BOTH than for either HI-2HGLU or LO-BOTH (all P < 0.001). Those with Index60 values above the median were younger and had higher frequency of two or more Ab⁺ (P < 0.001) and DR3-DQ2/DR4-DQ8 prevalence (P < 0.001) and lower area under the curve (AUC) C-peptide levels (P < 0.001) than those below. Those above the 2-h glucose median had higher AUC C-peptide levels (P < 0.001), but otherwise did not differ from those below.

Index60 identifies individuals with characteristics of type 1 diabetes at appreciable risk for progression who would otherwise be missed by 2-h glucose staging criteria.

我们评估了 Index60（空腹 C 肽、60 分钟 C 肽和 60 分钟葡萄糖的综合测量值）是否可以改善自身抗体阳性的 1 型糖尿病进展为临床疾病（第 3 期）的代谢分期。 Ab ⁺ ) 具有正常 2 小时葡萄糖值 (<140 mg/dL) 的个体。

我们分析了 3,058 名 2 小时葡萄糖 <140 mg/dL 和 Index60 <1.00 基线口服葡萄糖耐量测试值的 1 型糖尿病 TrialNet 预防参与者。在四个相互排斥的组中比较了与 1 型糖尿病相关的特征（年龄较小、Ab ⁺较高、HLA DR3-DQ2/DR4-DQ8 患病率较高和 C 肽较低）：仅前 2 小时葡萄糖四分位数（HI-2HGLU )、仅前四分位数 Index60 (HI-IND60)、前四分位数 (HI-BOTH) 和前四分位数 (LO-BOTH)。此外，在 <140 mg/dL 的 2 小时葡萄糖分布内和 Index60 <1.00 分布内，分别在中位数以上或以下之间进行了比较。

与HI-2HGLU 或 LO-BOTH 相比， HI-IND60 和 HI-BOTH 更年轻，出现两个以上 Ab ⁺的频率更高，C 肽水平更低（所有P < 0.001）。HI-IND60 和 HI-BOTH 在第 3 阶段的累积发病率高于 HI-2HGLU 或 LO-BOTH（所有P < 0.001）。Index60 值高于中位数的人更年轻，两种或两种以上 Ab ⁺ ( P < 0.001) 和 DR3-DQ2/DR4-DQ8 患病率 ( P < 0.001) 的频率较高，曲线下面积 (AUC) C 肽较低水平 ( P < 0.001) 低于以下水平。高于 2 小时葡萄糖中位数的人具有更高的 AUC C 肽水平（P< 0.001)，但除此之外与下面的没有区别。

Index60 可识别具有 1 型糖尿病特征且具有明显进展风险的个体，否则 2 小时血糖分期标准会遗漏这些个体。