不同糖调节受损人群的血糖波动特征

目的 研究不同糖调节受损人群的动态血糖波动特征.方法 采用动态血糖监测系统(CGMS)根据连续2次口服葡萄糖耐量试验结果,选取稳定人群中单纯空腹血糖受损(IFG)组12例,单纯餐后血糖受损(IGT)组19例,空腹血糖受损合并糖耐量低减(IFG/IGT)组11例,新诊断2型糖尿病(T2DM)组21例,正常对照(NGT)组18例,分析其各项临床指标和CGMS动态血糖数据.结果 (1)日内血糖波动:NGT、IFG、IGT、IFG/IGT至T2DM组的最大血糖波动幅度(LAGE)、平均血糖(MBG)和血糖水平标准差(SDBG)依次升高.IGT组的平均血糖波动幅度(MAGE)(3.2±1.2)mmol/L较NGT组(1.6±0.5)mmol/L高,较T2DM组(5.2±1.9)mmol/L低(P<0.05);IFG/IGT的有效血糖波动频率(FGE)(5.5±2.5)次/d较NGT组(6.1±3.4)次/d低,较T2DM组(4.8±1.8)高.糖尿病前期3组间IGT组MAGE(3.2±1.2)mmol/L最高,FGE(4.9±1.8)最低.(2)日间血糖波动:与NGT组(0.8±0.3)mmo/L相比,IGT组(1.1±0.4)mmol/L、IFG/IGT组(1.2±0.4)mmol/L和T2DM组(2.0±1.0)mmol/L的日间血糖平均绝对差依次升高(P<0.05).(3)不同糖调节受损人群血糖波动特征:IFG组空腹血糖受损程度最重,餐后高峰以IFG/IGT组为著.血糖水平曲线由低至高依次为NGT、IGT、IFG/IGT、IFG、T2DM组.(4)不同HbAlc水平的血糖波动:受试者HbAlc<7%时,空腹血糖曲线几乎重合,餐后血糖曲线略微分开;HbAlc7.0%～7.9%时,餐后高峰明显上升;HbAlc≥8%时,空腹曲线明显上移,餐后波动继续升高.结论 (1)随着糖调节受损程度的加重,日内血糖波动及日间血糖波动逐渐增加.(2)正常人血糖波动幅度小,频率高;T2DM餐后血糖波动幅度大,有效波动频率低;(3)IFG组的血糖波动特征最接近于NGT,而IGT组最接近于T2DM;(4)在糖尿病前期阶段餐后血糖受损明显早于空腹.

Characteristics of glycemic excursion in different subtypes of impaired glucose intolerance

Objective To investigate the characteristics of glycemic excursion of different subtypes of glucose tolerance. Methods Assessed by oral glucose tolerance test (OGTT) repeated twice, 81 individuals were divided into 4 groups: normal glucose tolerance (NGT, n=18), isolated impaired fasting glycemia (IFG, n=12), isolated impaired glucose tolerance (IGT, n=19), combined IFG/IGT (n=11), and newly diagnosed type 2 diabetes mellitus (T2DM, n=21). And then continuous glucose monitoring system (CGMS) was used for 72 hours to monitor the blood glucose (BG) level before drug intervention. Results (1) The levels of largest amplitude of glycemic excursions (LAGE), mean blood glucose (MBG), and standard deviation of mean level of blood glucose fluctuation (SDBG) increased gradually with the deterioration of glucose tolerance. The mean amplitude of glucose excursion (MAGE) readout of the IGT group was (3.2±1.2) mmol/L , significantly higher than that of the NGT group (1.6±0.5) mmol/L, P<0.05], and significantly lower than that of the T2DM group (5.2±1.9) mmol/L, P<0.05]. The level of frequency of glucose excursion (FGE) decreased along with the decrease of glucose tolerance: NGT group (6.1±3.4)] > IGT/IFG group (5.5±2.5)] > T2DM group (4. 8±1.8)]. Among the three components of IGR, the IGT group showed highest MAGE (3.2±1.2) mmol/L and lowest FGE level (4.9±1.8). (2) The level of absolute mean of daily difference (MODD) increased in the following order: NGT group (0.8±0.3) mmol/L], IGT group (1.1±0.4) mmol/L], IFG/IGT group (1.2±0.4) mmol/L], and T2DM group (2.0±1.0) mmol/L] (all P<0.05). (3) The fasting glucose level deteriorated the most rapidly in the IFG group, while it reached the highest postprandial peak in the IFG/IGT group. The blood glucose curve increased along the order of NGT, I-IGT, IFG/IGT, IFG, and T2DM. (4) When the level of glycosylated hemoglobin (HbAlc) level was less than 7%, the fasting phase of curve virtually coincided with each other among individual groups with different HbAlc levels; however, the postprandial peak separated slightly. When the HbAlC level was between 7. 0% and 7.9% , the postprandial peaks of individual groups with different HbAlc levels dispersed markedly. When the HbAlc level was higher than 8% , the fasting blood glucose curve moved upwards significantly with increasing postprandial excursion. Conclusion (1) With the deterioration of glucose regulation, the intraday and day-to-day blood glucose excursions become increasingly fluctuant. (2) The amplitude of glycemic excursion is lower in the NGT group than in the T2DM group, however, the frequency of glycemic excursion is higher in the NGT subject than in the T2DM subjects. The glucose excursion profile of the IGR subjects is between the NGR and T2DM subjects. (3) The characteristics of glucose excursion of the IGT group are similar to those of the T2DM group, and the characteristics of the IFG group are similar to those of the NGT group. (4)The loss of postprandial glycemie control precedes evident deterioration in fasting phase of IGR.