Sitasuwan Tullaya, Lertwattanarak Raweewan
Department of Medicine, Mahidol University Faculty of Medicine Siriraj Hospital, Bangkok, Thailand.
Department of Medicine, Mahidol University Faculty of Medicine Siriraj Hospital, Bangkok, Thailand
BMJ Open. 2020 Nov 10;10(11):e041269. doi: 10.1136/bmjopen-2020-041269.
About 11%-30% of individuals with impaired fasting plasma glucose (IFG) have type 2 diabetes mellitus (T2DM), diagnosed by the 75 g oral glucose tolerance test (75 g OGTT). This study investigated (1) the prevalence and cut-off levels for fasting plasma glucose (FPG) and glycated haemoglobin A1c (HbA1c) in IFG individuals that most effectively predict the presence of T2DM diagnosed by a 75 g OGTT; (2) the predictors associated with T2DM; and (3) the pathophysiological characteristics of patients with IFG.
A single-centre, cross-sectional study was conducted in a primary care setting. A standard 75 g OGTT was performed on 123 subjects with IFG. Their beta-cell function and insulin resistance were calculated through plasma glucose and insulin levels monitored during the 75 g OGTT.
In the IFG subjects, the prevalence of T2DM using the 2-hour postload plasma glucose (2hPG) criterion was 28.5%. Pre-diabetes and normal glucose metabolism were found in 48.7% and 22.8%, respectively, by 75 g OGTT. An HbA1c level ≥6.0% or FPG ≥5.9 mmol/L were the optimal cut-off thresholds for the prediction of the presence of T2DM. HbA1c had a sensitivity of 76.7% and specificity of 55.7% (95% CI 57.7% to 90.1% and 95% CI 43.3% to 67.6%, respectively), while FPG had a sensitivity of 85.7% and specificity of 23.9% (95% CI 69.7% to 95.2% and 95% CI 15.4% to 34.1%, respectively). The presence of metabolic syndrome, a higher HbA1c and higher FPG levels were associated with the risk of T2DM in the Thai IFG population.
Almost one-third of the people with IFG had T2DM diagnosed by the 2hPG criterion. HbA1c was more effective than FPG in predicting the presence of T2DM in the IFG subjects. IFG individuals with HbA1c≥6.0% or FPG≥5.9 mmol/L should be advised to undergo a 75 g OGTT to detect T2DM earlier than otherwise.
空腹血糖受损（IFG）人群中，约11%-30%的个体通过75克口服葡萄糖耐量试验（75g OGTT）诊断为2型糖尿病（T2DM）。本研究调查了：（1）IFG个体中，最能有效预测通过75g OGTT诊断的T2DM存在的空腹血糖（FPG）和糖化血红蛋白A1c（HbA1c）的患病率及临界值；（2）与T2DM相关的预测因素；（3）IFG患者的病理生理特征。
在基层医疗环境中进行了一项单中心横断面研究。对123例IFG受试者进行了标准的75g OGTT。通过75g OGTT期间监测的血糖和胰岛素水平计算其β细胞功能和胰岛素抵抗。
在IFG受试者中，采用负荷后2小时血糖（2hPG）标准诊断的T2DM患病率为28.5%。通过75g OGTT发现，糖尿病前期和糖代谢正常者分别占48.7%和22.8%。HbA1c水平≥6.0%或FPG≥5.9 mmol/L是预测T2DM存在的最佳临界阈值。HbA1c的敏感性为76.7%，特异性为55.7%（95%CI分别为57.7%至90.1%和43.3%至67.6%），而FPG的敏感性为85.7%，特异性为23.9%（95%CI分别为69.7%至95.2%和15.4%至34.1%）。代谢综合征的存在、较高的HbA1c和FPG水平与泰国IFG人群的T2DM风险相关。
几乎三分之一的IFG患者通过2hPG标准诊断为T2DM。在预测IFG受试者中T2DM的存在方面，HbA1c比FPG更有效。应建议HbA1c≥6.0%或FPG≥5.9 mmol/L的IFG个体进行75g OGTT，以便比其他情况更早地检测出T2DM。
