新诊断标准下糖尿病前期人群胰岛β细胞功能和胰岛素敏感性的特点分析

Characteristic analysis of insulin secretion and sensitivity in pre-diabetes populations under new diagnostic criteria

目的·评估不同类型糖尿病前期人群的胰岛β细胞功能、胰岛素敏感性及血糖处置能力。方法·共纳入1 317例研究对象,其中糖耐量正常(normal glucose tolerance,NGT)382例,糖尿病前期935例。依据2010年美国糖尿病学会糖尿病前期的诊断标准,将糖尿病前期人群分为7个亚组。以稳态模型分析(homeostasis model assessment,HOMA)来评估基础胰岛β细胞分泌功能(HOMA-β)及胰岛素敏感性(HOMA-IR),以0～120 min胰岛素曲线下面积/血糖曲线下面积(area under curve for insulin/area under curve for glucose,AUC_(INS120)/AUC_(GLU120))来评估糖负荷后胰岛β细胞分泌功能,以Cederholm公式计算的胰岛素敏感性指数(insulin sensitivity index,ISI)来评估糖负荷后胰岛素敏感性。计算血糖处置指数(disposition index,DI)来反映血糖处置能力。结果·糖尿病前期人群中最常见的类型为空腹血糖受损(impaired fasting glucose,IFG)合并糖耐量受损(impaired glucose tolerance,IGT)合并糖化血红蛋白(glycated hemoglobin A_(1c),HbA_(1c))5.7%～6.4%,其次为单纯IGT,而单纯IFG占比最低。单纯HbA_(1c) 5.7%～6.4%组胰岛素敏感性优于单纯IFG、单纯IGT、IFG合并IGT亚组(均P<0.05),胰岛β细胞功能与其他亚组类似。单纯HbA_(1c) 5.7%～6.4%组DI约是单纯IGT及IFG合并IGT组的1.5倍(均P=0.000),与单纯IFG组差异无统计学意义。无论IFG、IGT还是IFG合并IGT人群,如合并HbA_(1c) 5.7%～6.4%,则其胰岛β细胞功能或胰岛素敏感性进一步下降。结论·新标准下不同类型糖尿病前期人群存在明显异质性,HbA_(1c) 5.7%～6.4%是否适用于中国人群作为糖尿病前期的诊断标准,尚需大样本的前瞻性研究来证实。

Objective·To investigate the characteristics of insulin secretion function and sensitivity and blood glucose disposition capacity in the prediabetes populations. Methods·A total of 1 317 subjects were enrolled in this study, including 382 with normal glucose tolerance（NGT） and 935 with pre-diabetes. All pre-diabetes populations were divided into seven subgroups according to the cut-off points of 2010 American Diabetes Association standards. Homeostasis model assessment（HOMA） was used to access baseline insulin secretion（HOMA-β） and insulin sensitivity（HOMA-IR）. Insulin secretion and sensitivity after glucose load were evaluated by area under curve（AUC） for insulin/AUC for glucose（AUC（INS120）/AUC（GLU120）） and insulin sensitivity index（ISI） calculated from Cederholm formula, respectively. Disposition index（DI） was used to reflect blood glucose disposition capacity. Results·The most common type of pre-diabetes was impaired fasting glucose（IFG） combined with impaired glucose tolerance（IGT） and glycated hemoglobin A1c（HbA1c） 5.7%-6.4%, followed by isolated IGT, while the proportion of isolated IFG was the lowest. The insulin sensitivity of isolated HbA1c 5.7%-6.4% group was better than that of isolated IFG group, isolated IGT group, and IFG combined with IGT group（P0.05）. And its β-cell function was similar with the other subgroups. The DI value of isolated HbA1c 5.7%-6.4% group was about 1.5 times of that of isolated IGT group and IFG combined with IGT group（P=0.000）, which was similar with isolated IFG group. The function of β cell or insulin sensitivity in the pre-diabetes subjects with HbA1c 5.7%-6.4% was further damaged compared with the pre-diabetes people whose HbA1c were lower than 5.7%. Conclusion·Different types of pre-diabetes are significantly heterogeneous under new diagnostic criteria, and further prospective studies with a larger sample size are needed to clarify whether HbA1c 5.7%-6.4% is suitable as a diagnostic criteria for pre-diabetes in Chinese population.