Department of Pediatrics, Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Center, Aurora, Colorado 80045, USA.
Department of Biostatistics, Colorado School of Public Health, Aurora, Colorado 80045, USA.
J Clin Endocrinol Metab. 2022 Jan 18;107(2):e548-e560. doi: 10.1210/clinem/dgab692.
Early glucose abnormalities in people with cystic fibrosis (PwCF) are commonly detected by continuous glucose monitoring (CGM). Relationships between these CGM abnormalities and oral glucose tolerance testing (OGTT) in PwCF have not been fully characterized.
This work aimed to determine the relationship between CGM and common OGTT-derived estimates of β-cell function, including C-peptide index and oral disposition index (oDI) and to explore whether CGM can be used to screen for OGTT-defined prediabetes and cystic fibrosis-related diabetes (CFRD).
PwCF not on insulin and healthy controls aged 6 to 25 years were enrolled in a prospective study collecting OGTT and CGM. A subset underwent frequently sampled OGTTs (fsOGTT) with 7-point glucose, insulin, and C-peptide measurements. Pearson correlation coefficient was used to test the association between select CGM and fsOGTT measures. Receiver operating curve (ROC) analysis was applied to CGM variables to determine the cutoff optimizing sensitivity and specificity for detecting prediabetes and CFRD.
A total of 120 participants (controls = 35, CF = 85), including 69 with fsOGTTs, were included. CGM coefficient of variation correlated inversely with C-peptide index (Cpeptide30-Cpeptide0/Glucose30-Glucose0) (r = -0.45, P < .001) and oDIcpeptide (C-peptide index)(1/cpep0) (r = -0.48, P < .0001). In PwCF, CGM variables had ROC - areas under the curve ranging from 0.43 to 0.57 for prediabetes and 0.47 to 0.6 for CFRD.
Greater glycemic variability on CGM correlated with reduced β-cell function. However, CGM performed poorly at discriminating individuals with and without OGTT-defined CFRD and prediabetes. Prospective studies are now needed to determine how well the different tests predict clinically relevant nonglycemic outcomes in PwCF.
囊性纤维化（CF）患者通常通过连续血糖监测（CGM）检测到早期血糖异常。这些 CGM 异常与 CF 患者口服葡萄糖耐量试验（OGTT）之间的关系尚未完全确定。
本研究旨在确定 CGM 与常用 OGTT 衍生的β细胞功能评估指标（包括 C 肽指数和口服处置指数（oDI））之间的关系，并探讨 CGM 是否可用于筛查 OGTT 定义的糖尿病前期和囊性纤维化相关糖尿病（CFRD）。
纳入了年龄在 6 至 25 岁之间的未接受胰岛素治疗的 CF 患者和健康对照者，进行前瞻性研究，收集 OGTT 和 CGM。亚组进行了 7 点血糖、胰岛素和 C 肽的频繁采样 OGTT（fsOGTT）。采用 Pearson 相关系数检验选择 CGM 和 fsOGTT 测量之间的关联。应用受试者工作特征曲线（ROC）分析 CGM 变量，确定优化灵敏度和特异性以检测糖尿病前期和 CFRD 的截断值。
共纳入 120 名参与者（对照组=35 名，CF 组=85 名），其中 69 名接受了 fsOGTT。CGM 变异系数与 C 肽指数（Cpeptide30-Cpeptide0/Glucose30-Glucose0）呈负相关（r=-0.45，P<0.001）和 oDIcpeptide（C 肽指数）（1/cpep0）（r=-0.48，P<0.0001）。在 CF 患者中，CGM 变量的 ROC 曲线下面积在预测糖尿病前期的范围为 0.43 至 0.57，预测 CFRD 的范围为 0.47 至 0.6。
CGM 上的血糖变异性越大，β细胞功能越低。然而，CGM 在区分 OGTT 定义的 CFRD 和糖尿病前期患者方面表现不佳。现在需要进行前瞻性研究，以确定不同测试在预测 CF 患者无血糖相关不良结局方面的效果。
