Hemoglobin A1c, Not Glycated Albumin, Can Independently Reflect the Ankylosing Spondylitis Disease Activity Score

OBJECTIVE: This study examined whether glycated hemoglobin (HbA1c) and glycated albumin (GA) are well correlated with the Ankylosing Spondylitis Disease Activity Score (ASDAS)-erythrocyte sedimentation rate (ESR), and ASDAS-C-reactive protein (CRP) in AS patients without medical conditions affecting the glycated protein levels. METHODS: The data of 76 patients with AS were analyzed. Univariate and multivariate analyses of the variables associated with ASDAS-ESR and ASDAS-CRP were performed using a linear regression test. The patients were divided into active and inactive AS groups based on an ASDAS-CRP of 2.1, and the variables between the two groups were compared. RESULTS: ASDAS-ESR did not correlated with either HbA1c or GA. ASDAS-CRP was positively correlated with HbA1c (r=0.315, p=0.006) and the white blood cell (r=0.288, p=0.012), and inversely correlated with hemoglobin (r=−0.241, p=0.036) and serum albumin (r=−0.262, p=0.022), but not GA. Multivariate analysis revealed HbA1c and white blood cell to be significantly correlated with ASDAS-CRP (β=0.234, p=0.033 and β=0.265, p=0.017). The mean HbA1c, not GA, of the active group was significantly higher than that of the inactive group (p=0.020). In addition, the optimal cut-off value of HbA1c was set to 5.6, and the patients with HbA1c ≥5.6 were found to have a 3.3 times higher risk of active AS than those without. CONCLUSION: HbA1c was significantly correlated with ASDAS-CRP, and could be a useful marker to reflect ASDAS-CRP in AS patients without medical conditions affecting the glycated protein levels.

Glycated Albumin Is a More Useful Glycation Index than HbA1c for Reflecting Renal Tubulopathy in Subjects with Early Diabetic Kidney Disease

BACKGROUND: The aim of this study was to investigate which glycemic parameters better reflect urinary N-acetyl-β-D-glucosaminidase (uNAG) abnormality, a marker for renal tubulopathy, in subjects with type 2 diabetes mellitus (T2DM) subjects with normoalbuminuria and a normal estimated glomerular filtration rate (eGFR). METHODS: We classified 1,061 participants with T2DM into two groups according to uNAG level—normal vs. high (>5.8 U/g creatinine)—and measured their biochemical parameters. RESULTS: Subjects with high uNAG level had significantly higher levels of fasting and stimulated glucose, glycated albumin (GA), and glycosylated hemoglobin (HbA1c) and lower levels of homeostasis model assessment of β-cell compared with subjects with normal uNAG level. Multiple linear regression analyses showed that uNAG was significantly associated with GA (standardized β coefficient [β]=0.213, P=0.016), but not with HbA1c (β=−0.137, P=0.096) or stimulated glucose (β=0.095, P=0.140) after adjusting confounding factors. In receiver operating characteristic analysis, the value of the area under the curve (AUC) for renal tubular injury of GA was significantly higher (AUC=0.634; 95% confidence interval [CI], 0.646 to 0.899) than those for HbA1c (AUC=0.598; 95% CI, 0.553 to 0.640), stimulated glucose (AUC=0.594; 95% CI, 0.552 to 0.636), or fasting glucose (AUC=0.558; 95% CI, 0.515 to 0.600). The optimal GA cutoff point for renal tubular damage was 17.55% (sensitivity 59%, specificity 62%). CONCLUSION: GA is a more useful glycation index than HbA1c for reflecting renal tubulopathy in subjects with T2DM with normoalbuminuria and normal eGFR.

Alternative biomarkers for assessing glycemic control in diabetes: fructosamine, glycated albumin, and 1,5-anhydroglucitol

The growing attention to alternative glycemic biomarkers including fructosamine, glycated albumin (GA), 1,5-anhydroglucitol (1,5-AG), is attributable to the limitations of the glycated hemoglobin (HbA1c) assay. It is important to recognize the conditions in which HbA1c levels may be difficult to interpret. Serum fructosamine and GA have been proposed useful tools for monitoring of short-term glycemic control. These biomarkers not only reflect well glycemic control in hematologic disorder, but also represent postprandial glucose fluctuation. Serum 1,5-AG may be useful for estimating within-day glucose variation. Use of these nontraditional tests can be more helpful in the management of diabetes as complement traditional measures. Further larger cohort studies are warranted to determine whether nontraditional biomarkers have potential utility for early diagnosis, management of diabetes, and prevention of diabetic complications.

The Glycated Albumin to Glycated Hemoglobin Ratio Might Not Be Associated with Carotid Atherosclerosis in Patients with Type 1 Diabetes

BACKGROUND: The ratio of glycated albumin to glycated hemoglobin (GA/A1c) is known to be elevated in subjects with type 2 diabetes mellitus (T2DM) who had decreased insulin secretion. Additionally, the carotid intima media thickness (IMT) is greater in T2DM patients with higher GA/A1c ratios. We investigated whether increased GA/A1c ratio and IMT are also associated in type 1 diabetes mellitus (T1DM), which is characterized by lack of insulin secretory capacity. METHODS: In this cross-sectional study, we recruited 81 T1DM patients (33 men, 48 women; mean age 44.1+/-13.0 years) who underwent carotid IMT, GA, and HbA1c measurements. RESULTS: The mean GA/A1c ratio was 2.90. Based on these results, we classified the subjects into two groups: group I (GA/A1c ratio or =2.90, n=45). Compared with group I, the body mass indexes (BMIs), waist circumferences, and IMTs were lower in group II. GA/A1c ratio was negatively correlated with BMI, urine albumin to creatinine ratio (P<0.001 for both), and both the mean and maximal IMT (P=0.001, both). However, after adjusting the confounding factors, we observed that IMT was no longer associated with GA/A1c ratio. CONCLUSION: In contrast to T2DM, IMT was not significantly related to GA/A1c ratio in the subjects with T1DM. This suggests that the correlations between GA/A1c ratio and the parameters known to be associated with atherosclerosis in T2DM could be manifested differently in T1DM. Further studies are needed to investigate these relationships in T1DM.

Serum glycated albumin as a new glycemic marker in pediatric diabetes

PURPOSE: Serum glycated albumin (GA) has been recently used as another glycemic marker that reflects shorter term glycemic control than glycated hemoglobin (HbA1c). Insulin secretory function and glycemic fluctuation might be correlated with the ratio of GA to HbA1c (GA/HbA1c) in diabetic adult patients. This study investigated the association of GA and GA/HbA1c ratio with the levels of fasting C-peptide, fasting plasma glucose in type 1 and type 2 pediatric diabetes. METHODS: Total 50 cases from 42 patients were included. The subjects were classified into type 1 diabetes mellitus (T1DM) (n=30) and type 2 diabetes mellitus (T2DM) (n=20) group. The associations among HbA1c, GA, and GA/HbA1c ratio were examined. The relationship between the three glycemic indices and fasting glucose, fasting C-peptide were analyzed. RESULTS: Mean values of GA, the GA/HbA1c ratio were significantly higher in T1DM than T2DM. GA (r=0.532, P=0.001), HbA1c (r=0.519, P=0.002) and the GA/HbA1c ratio (r=0.409, P=0.016) were correlated with the fasting plasma glucose. Fasting C-peptide level arranged 4.22+/-3.22 ng/mL in T2DM, which was significantly above the values in T1DM (0.26+/-0.49 ng/mL). There were no significant correlation between HbA1c and fasting C-peptide level. However, GA and the GA/HbA1c ratio exhibited inverse correlations with fasting C-peptide level (r=-0.214, P=0.002; r=-0.516, P<0.001). CONCLUSION: GA seems to more accurately reflects fasting plasma glucose level than HbA1c. GA, GA/HbA1c ratio appear to reflect insulin secretory function.

Review of the Potential Glycemic Markers Glycated Albumin and 1,5-anhydroglucitol / 임상당뇨병

The measure of HbA1c is the gold standard index of glycemic control in clinical practice for diabetes treatment and is well known as a risk marker for diabetes complications. However, HbA1C does not accurately reflect glucose fluctuations or the actual status of glycemic control for several days or weeks. HbA1c measurement can be confounded in the anemia, hemoglobinopathy, or renal impairment. In comparison, glycated albumin (GA), a ketoamine formed by binding of albumin and glucose, more accurately reflects short-term changes in plasma glucose and postprandial plasma hyperglycemia (PPH). GA is not affected by hemoglobin or dialysis. 1,5-Anhydroglucitol (1,5-AG), another glycemic marker, structurally resembles glucose and decreases with spikes of hyperglycemia exceeding the average renal threshold for glucose. Especially, 1,5-AG level is reflective of PPH or glycemic variability and becomes an increasingly important contributor in a moderately controlled glycemic state, even when HbA1c level is within the target range. Herein, the usefulness of and recent studies on GA and 1,5-AG are summarized. Further investigations about the associations between these glycemic markers and diabetes complications are needed.