Serum 1,5-anhydroglucitol when used with fasting plasma glucose improves the efficiency of diabetes screening in a Chinese population

Abstract

Serum 1,5-anhydroglucitol (1,5-AG) levels can not only accurately reflect the mean blood glucose over the previous 1-2 weeks in diabetic patients but also offers the advantage of representing postprandial glucose. To evaluate the clinical significance of 1,5-AG in diabetes detection, especially when used in combination with fasting plasma glucose (FPG), a total of 3098 participants at high risk for diabetes (1467 men, 1631 women) were enrolled. A total of 1471 (47.5%) participants were diagnosed with diabetes, and the mean 1,5-AG level in the diabetic group was significantly lower than that in non-diabetic group [12.5 (7.8-17.5) μg/mL vs. 20.5 (15.3-26.4) μg/mL, P < 0.001]. The optimal cut-off point was 15.9 μg/mL, for which the sensitivity, specificity, and area under the curve (AUC) were 69.2%, 72.3%, and 0.781, respectively. For the combination of FPG and 1,5-AG, the sensitivity, specificity, and AUC improved to 82.5%, 83.5%, and 0.912, respectively. This method helped 75.8% of the participants avoid an oral glucose tolerance test (OGTT), reducing the need to carry out the OGTT by 43.9% compared to the use of the FPG criterion only. In conclusion, the addition of FPG to serum 1,5-AG improves the efficiency of diabetes screening in the Chinese population.

Figure 1

Characteristics of 1,5-anhydroglucitol (1,5-AG) levels in the total group (a) compared with different FPG levels; (b) compared with different 2hPG levels; (c) compared with different HbA_1c levels). ^* P < 0.05 versus the former group, ^** P < 0.01 versus the former group. Abbreviation: 2hPG, 2-hour postload plasma glucose; FPG: fasting plasma glucose; HbA _1c, glycated hemoglobin A_1c.

Figure 2

ROC curves for 1,5-anhydroglucitol (1,5-AG) ((a) in the total group; (b) in the total group with combined model; (c) in the non-FDR subgroup; (d) in the FDR subgroup) in the diagnosis of diabetes. For the combination of FPG with serum 1,5-AG, the sensitivity, specificity, and AUC were 82.5%, 83.5%, and 0.912, respectively. As for the combination of FPG and HbA_1c, the sensitivity, specificity, and AUC were 74.4%, 91.2%, and 0.911, respectively. There was no significant difference in the AUCs (P > 0.05). However, the specificity and sensitivity differed significantly from each other (all P < 0.001). Abbreviation: AUC: area under the curve; FDR: first degree relative with diabetes; FPG: fasting plasma glucose; HbA _1c: glycated hemoglobin A_1c; ROC: receiver operating characteristic.

Figure 3

Screening strategies for detecting diabetes by an OGTT after use of (a) the FPG criteria, (b) the combination of FPG and HbA_1c, or (c) the combination of FPG and 1,5-AG. The proportions of the study population in specific diagnostic categories were: (a) FPG < 5.6 mmol/L to exclude and FPG ≥ 7.0 mmol/L to diagnose diabetes, with 43.1% participants needing an OGTT to confirm the diagnose. The sensitivity, specificity, PPV, and NPV for this strategy were 47.3%, 100%, 100%, and 67.7%, respectively. (b) As for the combined criteria of FPG and HbA_1c criteria, FPG < 5.6 mmol/L and HbA_1c < 5.7% to exclude diabetes, and FPG ≥ 7.0 mmol/L and/or HbA_1c ≥ 6.5% to confirm diabetes, 46.8% participants needed an OGTT. The sensitivity, specificity, PPV, and NPV for this strategy were 70.2%, 100%, 100%, and 78.8%, respectively. (c) With the combined FPG and 1,5-AG criteria, which are FPG < 5.6 mmol/L and 1,5-AG > 15.9 μg/mL for exclusion of diabetes, and FPG ≥ 7.0 mmol/L and/or 1,5-AG ≤ 15.9 μg/mL for the diagnosis of diabetes, only 24.2% participants needed an OGTT. The sensitivity, specificity, PPV, and NPV for this strategy were 78.7%, 72.3%, 72.0%, and 78.9%, respectively. Abbreviations: DM: diabetes mellitus; FPG: fasting plasma glucose; HbA _1c : glycated hemoglobin A_1c; NPV: negative predictive value; OGTT: oral glucose tolerance test; PPV: positive predictive value.