The Biostatistics Center, Milken Institute School of Public Health The George Washington University, Rockville, MD, USA.
Division of Pediatric Endocrinology, Diabetes, and Metabolism, UPMC Children's Hospital of Pittsburgh, Pittsburgh, PA, USA.
J Clin Endocrinol Metab. 2023 Sep 18;108(10):e1125-e1133. doi: 10.1210/clinem/dgad135.
Previous work found poor reproducibility for measures of glycemia in individuals at risk for dysglycemia. Differences between youth and adults have not been assessed. Using youth and adults in the Restoring Insulin Secretion Study, we tested variability and classification concordance for hemoglobin A1C (HbA1c), fasting and 2-hour glucose from oral glucose tolerance tests (OGTTs).
HbA1c and glucose on repeated samples obtained ∼6 weeks apart were compared in 66 youth (mean age 14.2 years) and 354 adults (52.7 years). Changes, coefficient of variation (CV), and concordance of diagnostic categories between the 2 visits were compared.
Mean difference between the 2 visits in HbA1c was higher in youth than adults (P < .001), while fasting glucose was similar and 2-hour glucose was lower in youth (P = .051). CV was smallest for HbA1c compared to fasting and 2-hour glucose. For HbA1c, youth had higher CV (P < .001); whereas CV for 2-hour glucose was lower for youth (P = .041). Classification concordance by HbA1c was lower in youth (P = .004). Using OGTT or HbA1c for classification, intervisit variability produced discordant classification in 20% of youth and 28% of adults. Using both fasting glucose and HbA1c, intervisit variability reduced discordant classification to 16% of adults while not improving classification in youth.
Poor reproducibility and lack of classification concordance highlight the limitations of one-time testing, with important implications for assessing eligibility in clinical trials. Consideration should be given to using more than a single parameter for screening and diagnosis, especially when classification category is important.
先前的研究发现，对于处于糖调节受损风险的个体，血糖测量的重复性较差。尚未评估青年人（youth）和成年人（adults）之间的差异。本研究利用来自于“恢复胰岛分泌研究（Restoring Insulin Secretion Study）”的青年人（mean age 14.2 years）和成年人（52.7 years）数据，测试了血红蛋白 A1C（HbA1c）、空腹和口服葡萄糖耐量试验（OGTT）两小时血糖的变异性和分类一致性。
比较了 66 例青年人（mean age 14.2 years）和 354 例成年人（52.7 years）在大约 6 周内重复采样时的 HbA1c 和血糖值。比较了两次就诊之间的变化、变异系数（CV）和诊断类别之间的一致性。
青年人两次就诊之间的 HbA1c 差值大于成年人（P <.001），而空腹血糖相似，青年人的两小时血糖较低（P =.051）。与空腹血糖和两小时血糖相比，HbA1c 的 CV 最小。与空腹血糖和两小时血糖相比，青年人的 CV 更高（P <.001）；而青年人的两小时血糖 CV 较低（P =.041）。HbA1c 的分类一致性在青年人中较低（P =.004）。使用 OGTT 或 HbA1c 进行分类，20%的青年人（youth）和 28%的成年人（adults）的两次就诊之间的变异性导致分类不一致。使用空腹血糖和 HbA1c 两者，两次就诊之间的变异性将成年人的不一致分类减少到 16%，而青年人的分类改善不明显。
重复性差和分类一致性差突出了单次检测的局限性，这对临床试验中的资格评估具有重要意义。在筛选和诊断时，应考虑使用多个参数，特别是当分类类别很重要时。
