上海地区中国人餐后血糖状态的特征

目的探讨正常糖调节(NGR)及2型糖尿病(T2DM)个体餐后血糖状态的特征以及T2DM患者餐前、餐后血糖与糖化血红蛋白(HbA1c)的关系。方法采用动态血糖监测系统对上海地区41例NGR及60例新诊断T2DM个体进行连续3d的血糖监测,分析比较餐后血糖峰值与达峰时间,以及餐后血糖漂移的幅度(PPGE)、时间和曲线下面积增值(IAUC)。结果(1)三餐后血糖峰值、达峰时间及PPGE在T2DM组(早餐16·45mmol/L±0·43mmol/L、93·1min±4·7min、6·84mmol/L±0·28mmol/L,中餐14·75mmol/L±0·50mmol/L、107·4min±6·5min、4·93mmol/L±0·31mmol/L,晚餐14·91mmol/L±0·45mmol/L、109·3min±4·9min、5·84mmol/L±0·28mmol/L)显著高于NGR组(早餐6·90mmol/L±0·21mmol/L、40·8min±2·9min、2·02±0·17mmol/L,中餐6·74mmol/L±0·16mmol/L、43·7min±3·1min、2·03±0·12mmol/L,晚餐6·94mmol/L±0·19mmol/L、53·5min±3·8min、2·25mmol/L±0·18mmol/L,均P<0·01)。日内餐后血糖漂移时间及IAUC在T2DM组(14·1h±0·3h,2·04mmol·L-1·d±0·09mmol·L-1·d)亦显著高于NGR组(8·3h±0·4h,0·43mmol·L-1·d±0·03mmol·L-1·d,均P<0·01)。(2)T2DM组早餐后血糖较快达到尖峰(P<0·05),且峰值显著高于中、晚餐(P<0·01),PPGE从高到低的顺序分别为早、晚及中餐(P<0·05),晚餐的IAUC显著高于早、中餐(P<0·01)。(3)HbA1c与IAUC的相关性(r=0·29,P=0·03)在调整餐前血糖的因素后消失(P=0·05);PPGE与IAUC呈显著正相关(r=0·93,P<0·01)。(4)T2DM组餐后血糖对总体日内血糖的贡献百分比显著高于NGR组(18·1%±0·8%比8·0%±0·7%,P<0·01),但均显著低于其餐前血糖(P<0·01)。(5)当HbA1c<7·5%时,餐后血糖升高部分对总体日内高血糖的贡献大于餐前血糖(P<0·05),当HbA1c≥7·5%时,餐前高血糖的相对作用逐渐增加并占主要作用(P<0·01)。结论(1)T2DM患者表现为餐后血糖的过度漂移并持续较长时间,同时伴有血糖尖峰的延迟,其餐后急性高血糖状态以早餐最明显。(2)HbA1c不能反映餐后血糖的漂移变化,PPGE可作为估测餐后血糖漂移程度的简易临床参数。(3)在轻、中度高血糖的患者中,餐后高血糖起主要作用,提示血糖控制越接近达标,餐后血糖的控制越重要。

The features of postprandial glucose state in type 2 diabetes mellitus

OBJECTIVE: To study the features of postprandial glucose state in individuals with normal glucose regulation (NGR) and type 2 diabetes (T2DM) and the relations between hemoglobin A1c (HbA1c) and postprandial glucose in T2DM. METHODS: 41 NGR individuals and 60 newly diagnosed T2DM patients without previous management in Shanghai were measured by continuous glucose monitoring system for 3 days. The postprandial glucose spike (PGS), time to PGS (Deltat), postprandial glucose excursion (PPGE), duration of postprandial glucose (DUR) and incremental area under the curve of postprandial glucose (IAUC) were calculated in each individual. RESULTS: (1) The levels of PGS and Deltat in the T2DM group were significantly higher than those of the NGR group (all P < 0.01). The levels of PPGE, DUR and IAUC of the T2DM group were 5.87 mmol/L +/- 0.19 mmol/L, 14.1 h +/- 0.3 h and 2.04 mmol.L(-1).d +/- 0.09 mmol.L(-1).d respectively, all significantly higher than those of the NGR group (2.10 mmol/L +/- 0.12 mmol/L, 8.3 h +/- 0.4 h and 0.43 mmol.L(-1).d +/- 0.03 mmol.L(-1).d respectively, all P < 0.01). The breakfast had higher PGS and lower Deltat than those of lunch and dinner in the T2DM group (both P < 0.01). The PPGE was arranged from high to low in the order of breakfast, dinner and lunch. The highest IAUC appeared during dinner. (2) There was a significantly correlation between PPGE and IAUC (r = 0.93, P < 0.01) in the T2DM group. After being adjusted by preprandial glucose, the partial correlation of HbA1c and IAUC disappeared (before r = 0.29, P = 0.03, after P = 0.05). (3) The relative contribution of postprandial glucose to overall glucose levels in the T2DM group was significantly higher than that of the NGR group (18.1% +/- 0.8% vs 8.0% +/- 0.7%, P < 0.01), but both were significantly lower than those of preprandial glucose. (4) Relative contribution of postprandial hyperglycemia to overall diurnal hyperglycemia decreased progressively from the lowest to the highest quarter of HbA1c. By contrast, the relative contribution of preprandial hyperglycemia showed a significant increase with increasing levels of HbA1c. Postprandial hyperglycemia played a major role when the HbA1c level below 7.5% (P < 0.05). CONCLUSION: (1) The features of postprandial glucose state in T2DM is representative in the delay of PGS and excessive glucose excursion for a long time after the ingestion of a meal. (2) HbA1c can't reflect postprandial glucose excursions. PPGE can be used as a simple clinic index to evaluate the amplitude of postprandial glucose excursions. (3) Postprandial glucose excursions play a major role in T2DM suffering from mild or moderate hyperglycemia. The present results suggest that postprandial hyperglycemia is an important target for intervention when T2DM patients are approaching the ideal glycemic control.