Search

The aim of this study was to evaluate the utility of hemoglobin A1c (HbA1c) to identify individuals with diabetes and prediabetes in the Japanese population. A total of 1372 individuals without known diabetes were selected for this study. A 75 g oral glucose tolerance test (OGTT) was used to diagnose diabetes and prediabetes. The ability of HbA1c to detect diabetes and prediabetes was investigated using receiver operating characteristic (ROC) analysis. The kappa (κ) coefficient was used to test the agreement between HbA1c categorization and OGTT-based diagnosis. ROC analysis demonstrated that HbA1c was a good test to identify diabetes and prediabetes, with areas under the curve of 0.918 and 0.714, respectively. Optimal HbA1c cutoffs for diagnosing diabetes and prediabetes were 6.0% (sensitivity 83.7%, specificity 87.6%) and 5.7% (sensitivity 60.6%, specificity 72.1%), respectively, although the cutoff for prediabetes showed low accuracy (67.6%) and a high false-negative rate (39.4%). Agreement between HbA1c categorization and OGTT-based diagnosis was low in diabetes (κ=0.399) and prediabetes (κ=0.324). In Japanese subjects, the HbA1c cutoff of 6.0% had appropriate sensitivity and specificity for diabetes screening, whereas the cutoff of 5.7% had modest sensitivity and specificity in identifying prediabetes. Thus, HbA1c may be inadequate as a screening tool for prediabetes. [ABSTRACT FROM AUTHOR]

Background: Increased triglycerides (TGs) and decreased high density lipoprotein cholesterol (HDL-C) levels are established as diabetic risks for nondiabetic subjects. The aim of this study was to investigate the relationship among TG, HDL-C, TG/HDL-C ratio, and early-phase insulin secretion in normoglycemic and prediabetic subjects. Methods: We evaluated 663 Japanese subjects who underwent the 75-g oral glucose tolerance test. On the basis of these results, the subjects were divided into four groups: those with normal glucose tolerance (NGT; n=341), isolated impaired fasting glucose (i-IFG; n=211), isolated impaired glucose tolerance (i-IGT; n=71), and combined IFG and IGT (IFG+IGT; n=40). Insulin secretion was estimated by the insulinogenic index (IGI) (?insulin/?glucose [30 to 0 minutes]) and disposition index (DI) (IGI/ homeostasis model assessment of insulin resistance). Results: In prediabetic subjects (i-IFG, i-IGT, and IFG+IGT), linear regression analyses revealed that IGI and DI were positively correlated with HDL-C levels. Moreover, in subjects with i-IGT and (IFG+IGT), but not with i-IFG, the indices of insulin secretion were negatively correlated with the log-transformed TG and TG/HDL-C ratio. In both the subjects with i-IGT, multivariate linear regression analyses revealed that DI was positively correlated with HDL-C and negatively with log-transformed TG and TG/HDL-C ratio. On the other hand, in subjects with NGT, there was no association between insulin secretion and lipid profiles. Conclusion: These results revealed that serum TG and HDL-C levels have different impacts on early-phase insulin secretion on the basis of their glucose tolerance status. [ABSTRACT FROM AUTHOR]

Background: One-hour plasma glucose (1-h PG) level of ≥ 155 mg/dL during an oral glucose tolerance test (OGTT) predicts the development of type 2 diabetes mellitus among individuals with normal glucose tolerance (NGT). In addition, high triglyceride (TG) and low high-density lipoprotein-cholesterol (HDL-C) levels are risks factors for development of diabetes mellitus in the future. Objective: To examine the association between 1-h PG levels and serum lipid profiles in individuals with NGT. Methods: We enrolled 736 individuals with NGT who underwent a 75-g OGTT. They were divided into 2 groups, those with 1-h PG levels < 155 mg/dL (n = 543) and those with 1-h PG levels ≥ 155 mg/dL (n = 193). Multivariate linear regression analyses were performed to assess correlations between 1-h PG levels and lipid profiles. Results: The multiple linear regression analyses showed that 1-h PG levels negatively correlated with HDL-C in individuals with NGT who had 1-h PG levels ≥ 155 mg/dL as well as those with 1-h PG levels < 155 mg/dL (β = −0.137, P = .001 and β = −0.214, P = .003, respectively). In addition, 1-h PG levels positively correlated with log-transformed TG/HDL-C ratio in both groups (β = 0.098, P = .032 and β = 0.152, P = .035, respectively). Moreover, even after adjusting for confounding parameters, TG was higher and HDL-C was lower in individuals with NGT who had 1-h PG levels ≥ 155 mg/dL compared with those who had 1-h PG levels < 155 mg/dL. Conclusion: HDL-C levels and TG/HDL-C ratios closely correlate with 1-h PG levels in individuals with NGT. [Copyright &y& Elsevier]