To compare clinical characteristics of impaired glucose regulation (IGR) diagnosed with oral glucose tolerance test (OGTT) and prediabetes (PreDM) with glycated hemoglobin A_1c (HbA_1c).

This was a cross-sectional study. A total of 402 subjects who were high-risk for diabetes from Yanqing District in Beijing underwent a 75 g OGTT and an HbA_1c test during July 2019 to November 2019. The data of height, weight, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were collected. Fasting plasma glucose (FPG), 2-hour postload blood glucose (2 h PG), fasting insulin (FINS), 2-hour postload insulin (2 h INS), triglyceride (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and high-density lipoprotein-cholesterol (HDL-C) were examined. The body mass index (BMI), homeostasis model assessment of β cell function (HOMA-β), homeostasis model assessment of insulin resistance (HOMA-IR) and Matsuda index were calculated. According to the 2019 American Diabetes Association criteria, the patients were divided into IGR group and PreDM group. All indicators between two groups were compared using independent samplest test or Mann-Whitney U test. One-way analysis of variance or Kruskal-Wallis H test were used for multiple comparisons. The enumeration data were compared using Chi-squared test.

A total of 397 subjects were included after excluding 5 subjects with hemoglobin<110 g/L. Of which, 161 (40.6%) were IGR and 188 (47.4%) were PreDM. The BMI [(28.7±9.2) vs (26.1±3.7) kg/m², t=-3.335, P<0.05] and Matsuda index [4.64 (3.21, 6.89) vs 4.08 (2.85, 5.95),Z=-2.443, P<0.05] in IGR group were lower than those in PreDM group, and the levels of FPG [(5.7±0.5) vs (5.9±0.6) mmol/L,t=3.611, P<0.01], 2 h PG [(7.4±1.9) vs (8.7±1.6) mmol/L,t=6.757, P<0.01] and 2 h INS [(56.8±45.7) vs (69.3±50.5) mU/L,t=2.418, P<0.05] were higher than those in PreDM group. There were no significant differences in the level of SBP, DBP, FINS, HbA_1c, TG, TC, LDL-C, HDL-C, HOMA-β and HOMA-IR between two groups (all P>0.05). Compared to IGR subgroup with HbA_1c<5.7%, 2 h PG and 2 h INS were lower while level of HbA_1c was higher in PreDM subgroup (all P<0.05). There were no significant differences in the level of BMI, SBP, DBP, FPG, FINS, TG, TC, LDL-C, HDL-C, HOMA-β, HOMA-IR and Matsuda index between two groups (allP>0.05).

IGR and HbA_1c-defined PreDM not only have different hyperglycemic profiles, but also varies in BMI, insulin resistance and β cell function.

Hemoglobin A, glycosylated; Prediabetic state; Oral glucose tolerance test; Insulin resistance; β cell function