Serum Glycated Albumin to Guide the Diagnosis of Diabetes Mellitus.

In the diagnosis of diabetes mellitus, hemoglobin A1c (HbA1c) is sometimes measured to determine the need of an oral glucose tolerance test (OGTT). However, HbA1c does not accurately reflect glycemic status in certain conditions. This study was performed to test the possibility that measurement of serum glycated albumin (GA) better assesses the need for OGTT. From 2006 to 2012, 1559 subjects not known to have diabetes or to use anti-diabetic medications were enrolled. Serum GA was measured, and a 75-g OGTT was then performed to diagnose diabetes. Serum GA correlated significantly to age (r = 0.27, p<0.001), serum albumin (r = -0.1179, age-adjusted p = 0.001), body mass index (r = -0.24, age-adjusted p<0.001), waist circumference (r = -0.16, age-adjusted p<0.001), and plasma GA (r = 0.999, p<0.001), but was unaffected by diet (p = 0.8). Using serum GA at 15% for diagnosis of diabetes, the sensitivity, specificity, and area under the receiver-operating characteristic curve were 74%, 85%, and 0.86, respectively. Applying a fasting plasma glucose (FPG) value of < 100 mg/dL to exclude diabetes and of ≥ 126 mg/dL to diagnose diabetes, 14.4% of the study population require an OGTT (OGTT%) with a sensitivity of 78.8% and a specificity of 100%. When serum GA value of 14% and 17% were used to exclude and diagnose diabetes, respectively, the sensitivity improved to 83.3%, with a slightly decrease in specificity (98.2%), but a significant increase in OGTT% (35%). Using combined FPG and serum GA cutoff values (FPG < 100 mg/dL plus serum GA < 15% to exclude diabetes and FPG ≥ 126 mg/dL or serum GA ≥ 17% to diagnose diabetes), the OGTT% was reduced to 22.5% and the sensitivity increased to 85.6% with no change in specificity (98.2%). In the diagnosis of diabetes, serum GA measurements can be used to determine the need of an OGTT.

Plasma apelin: A novel biomarker for predicting diabetes.

BACKGROUND: Apelin regulates insulin sensitivity and secretion in animals. However, whether plasma apelin predicts incident diabetes in humans remains unknown. METHODS: We studied a cohort including 447 subjects (148 men, 299 women) without diabetes and followed for an average of 3y. Diabetes was diagnosed by an oral glucose tolerance test, plasma hemoglobin A1c, and if the subject was taking medications for diabetes. Plasma apelin-12 at baseline was measured with a commercial kit. RESULTS: Plasma apelin concentrations were higher in women than in men at baseline (p=0.007). During follow-up, 43 subjects developed type 2 diabetes. Higher plasma apelin concentrations were associated with a higher risk of diabetes in men (p=0.049) but not in women. Plasma apelin predicted incident type 2 diabetes in men (hazard ratio, 2.13, 95% CI 1.29-3.51, p<0.05), but not in women, adjusted for age, family history of diabetes, hemoglobin A1c, body mass index, hypertension, and HOMA2-IR. Apelin could improve the prediction ability beyond traditional risk factors in men, and the sensitivity and specificity of plasma apelin at 0.9ng/ml for this prediction were 63.2% and 58.9%, respectively. In men at risk for diabetes (HbA1c 5.7-6.4%, FPG 100-125mg/dl, or OGTT-2h-PG 140-199mg/dl), the risk for developing diabetes was higher in those with higher plasma apelin concentration than in those with lower plasma apelin concentrations (10.6%/year vs. 5.1%/year, p<0.001). CONCLUSIONS: Plasma apelin is a novel biomarker for predicting type 2 diabetes in men.