Objective: To investigate the appropriate cut-off point of time in range (TIR) for evaluating glucose control in type 2 diabetes mellitus (T2DM) patients, and analyze the prevalence of abnormal carotid intima-media thickness (CIMT) and diabetic retinopathy (DR) in different TIR categories. Methods: A total of 2 161 subjects with T2DM (1 183 males) were enrolled from hospitalized patients at the Department of Endocrinology and Metabolism of the Sixth People's Hospital Affiliated to Shanghai Jiao Tong University from January 2005 to February 2012. The age of the enrolled participants was (60.4±11.9) years. Each patient underwent continuous glucose monitoring (CGM) for three consecutive days, then TIR (3.9-10.0 mmol/L), time above range (TAR) and time below range (TBR) were calculated. Fundus photography and carotid artery Doppler ultrasound were performed to diagnose DR and abnormal CIMT (defined as CIMT≥1.0 mm), respectively. Multivariate logistic regression models were used to examine the independent association of different TIR groups with CIMT and DR. Results: All subjects were divided into 4 groups according to TIR:≤40%, 41%-70%, 71%-85% and>85%. Significant linear trends in age, diabetes duration, body mass index (BMI), total cholesterol, glycated hemoglobin A1c (HbA1c), TAR and mean glucose (MG) existed among the 4 groups (all P(trend)<0.05). However, there was only a weak correlation between TIR and TBR (<3.9 mmol/L) (r=0.087, P<0.001), and no significant association was observed between TBR (<3 mmol/L) and the TIR categories (P(trend)=0.378). The overall prevalence of abnormal CIMT and DR was 12.1% and 23.8%, respectively. The prevalence of abnormal CIMT in the 4 groups with ascending levels of TIR was 16.9% (59/349), 12.9% (96/746), 11.2% (57/510) and 9.0% (50/556) (P(trend)<0.001), respectively. And the prevalence of DR was 30.7% (107/349), 29.4% (219/746), 20.8% (106/510) and 14.9% (83/556), respectively (P(trend)<0.001). In the binary logistic regression model by adjusting confounding factors, compared with TIR≤ 40%, the risk of abnormal CIMT was reduced by 33.8% (OR=0.662, 95%CI: 0.456-0.963, P=0.031), 40.8% (OR=0.592, 95%CI: 0.390-0.899, P=0.014), and 45.0% (OR=0.550, 95%CI: 0.358-0.846, P=0.006) in the other three groups, respectively. And the risk of DR was reduced by 2.9% (OR=0.971, 95%CI: 0.725-1.301, P=0.844), 33.4%(OR=0.666, 95%CI: 0.479-0.924, P=0.015) and 53.3% (OR=0.467, 95%CI: 0.331-0.657, P<0.001), respectively. Conclusion: Using 40%, 70% and 85% as cut-off point of TIR helps stratify the risk of diabetic complications, and assess the glucose control (Poor: TIR≤40%; Unsatisfactory: TIR≤70%; Satisfactory: TIR>70%; Optimal: TIR>85%) in patients with T2DM.
目的： 探讨应用葡萄糖在目标范围内时间（TIR）评价2型糖尿病患者血糖控制情况的适宜切点。 方法： 纳入2005年1月至2012年2月上海交通大学附属第六人民医院内分泌代谢科的2 161例2型糖尿病患者（男1 183例），年龄（60.4±11.9）岁，收集患者基本资料、眼底及颈动脉超声检查结果，所有患者接受连续3 d的持续葡萄糖监测（CGM），计算TIR（3.9~10.0 mmol/L）以及葡萄糖高于目标范围时间（TAR）和葡萄糖低于目标范围时间（TBR）。根据各TIR切点进行分组后，分析比较各组颈动脉内膜中层厚度（CIMT）异常增厚（≥1.0 mm）和糖尿病视网膜病变（DR）的检出率情况。 结果： 根据TIR水平分为TIR≤40%、41%~70%、71%~85%及>85%共4组。4组间的年龄、糖尿病病程、体质指数（BMI）、总胆固醇（TC）、糖化血红蛋白（HbA1c）、TAR、平均葡萄糖（MG）呈现出随TIR减小而增加的趋势（所有趋势P<0.05），但TIR与TBR（<3.9 mmol/L）仅存在弱相关性（r=0.087，P<0.001），TBR（<3 mmol/L）未呈现出随TIR增加而降低的趋势（趋势P=0.378）。共有262例（12.1%）患者CIMT异常增厚，515例（23.8%）患者患有DR。异常CIMT在上述4组中患病率分别为16.9%（59/349）、12.9%（96/746）、11.2%（57/510）和9.0%（50/556）（趋势P<0.001）；DR患病率分别为30.7%（107/349），29.4%（219/746），20.8%（106/510）和14.9%（83/556）（趋势P<0.001）。在使用多因素logistic回归校正了协变量后，与TIR≤40%组相比，其余3组异常CIMT风险依次降低33.8%（OR=0.662，95%CI：0.456~0.963，P=0.031）、40.8%（OR=0.592，95%CI：0.390~0.899，P=0.014）和45.0%（OR=0.550，95%CI：0.358~0.846，P=0.006）；DR风险依次降低2.9%（OR=0.971，95%CI：0.725~1.301，P=0.844）、33.4%（OR=0.666，95%CI：0.479~0.924，P=0.015）及53.3%（OR=0.467，95%CI：0.331~0.657，P<0.001）。 结论： 采用40%、70%、85%作为TIR切点可对2型糖尿病患者的糖尿病相关并发症风险进行有效区分，建议作为评价2型糖尿病患者血糖控制差（TIR≤40%）、未达标（TIR≤70%）、达标（TIR>70%）以及优（TIR>85%）的评价切点。.
Keywords: Diabetes complications; Diabetes mellitus, type 2; Glucose control; Time in range.