Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People's Hospital; Shanghai Clinical Center for Diabetes; Shanghai Key Clinical Center for Metabolic Disease; Shanghai Diabetes Institute; Shanghai Key Laboratory of Diabetes Mellitus, Shanghai 200233, China.
Shanghai Clinical Center for Metabolic Diseases, Shanghai Key Laboratory of Diabetes Mellitus, Shanghai Diabetes Institute, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
Chin Med J (Engl). 2022 Aug 20;135(16):1978-1985. doi: 10.1097/CM9.0000000000002140.
Corneal confocal microscopy (CCM) is a noninvasive technique to detect early nerve damage of diabetic sensorimotor polyneuropathy (DSPN). Time in range (TIR) is an emerging metric of glycemic control which was reported to be associated with diabetic complications. We sought to explore the relationship between TIR and corneal nerve parameters in asymptomatic patients with type 2 diabetes (T2DM).
In this cross-sectional study, 206 asymptomatic inpatients with T2DM were recruited. After 7 days of continuous glucose monitoring, the TIR was calculated as the percentage of time in the glucose range of 3.9 to 10.0 mmol/L. CCM was performed to determine corneal nerve fiber density, corneal nerve branch density, and corneal nerve fiber length (CNFL). Abnormal CNFL was defined as ≤15.30 mm/mm 2 .
Abnormal CNFL was found in 30.6% (63/206) of asymptomatic subjects. Linear regression analyses revealed that TIR was positively correlated with CCM parameters both in the crude and adjusted models (all P < 0.05). Each 10% increase in TIR was associated with a 28.2% (95% CI: 0.595-0.866, P = 0.001) decreased risk of abnormal CNFL after adjusting for covariates. With the increase of TIR quartiles, corneal nerve fiber parameters increased significantly (all P for trend <0.01). The receiver operating characteristic curve indicated that the optimal cutoff point of TIR was 77.5% for predicting abnormal CNFL in asymptomatic patients.
There is a significant independent correlation between TIR and corneal nerve fiber loss in asymptomatic T2DM patients. TIR may be a useful surrogate marker for early diagnosis of DSPN.
角膜共焦显微镜（CCM）是一种非侵入性技术，可用于检测糖尿病感觉运动多发性神经病（DSPN）的早期神经损伤。时间在目标范围内（TIR）是一种新兴的血糖控制指标，据报道与糖尿病并发症有关。我们旨在探讨 TIR 与无症状 2 型糖尿病（T2DM）患者角膜神经参数之间的关系。
在这项横断面研究中，招募了 206 名无症状的 T2DM 住院患者。在连续血糖监测 7 天后，计算 TIR 作为血糖在 3.9 至 10.0 mmol/L 范围内的时间百分比。进行 CCM 以确定角膜神经纤维密度、角膜神经分支密度和角膜神经纤维长度（CNFL）。异常 CNFL 定义为≤15.30mm/mm2。
在 30.6%（63/206）的无症状受试者中发现异常 CNFL。线性回归分析显示，TIR 在未调整和调整模型中均与 CCM 参数呈正相关（均 P<0.05）。TIR 每增加 10%，与异常 CNFL 的风险降低 28.2%（95%CI：0.595-0.866，P=0.001）相关，调整协变量后。随着 TIR 四分位数的增加，角膜神经纤维参数显著增加（趋势 P 值均<0.01）。受试者工作特征曲线表明，TIR 的最佳截断点为 77.5%，用于预测无症状 T2DM 患者的异常 CNFL。
在无症状 T2DM 患者中，TIR 与角膜神经纤维丢失之间存在显著的独立相关性。TIR 可能是 DSPN 早期诊断的有用替代标志物。
