HbA1c reflects average glucose levels over 3 months, but it does not measure glycemic variability. This study aimed to determine the reproducibility and usefulness of HbA1c-derived estimated average glucose (eAG) and to analyze the factors associated with eAG during health checkups. This cross-sectional retrospective study consecutively selected subjects who had undergone health checkups at 16 health-promotion centers in 13 Korean cities in 2020. The subjects comprised 182,848 healthy subjects with normoglycemia, 109,555 with impaired fasting glucose (IFG), and 35,632 with diabetes. eAG was calculated using Nathan’s regression equation. In all subjects, fasting plasma glucose (FPG) was found to be fairly strongly correlated with eAG (r = 0.811). When the subjects were divided into FPG subgroups, the strength of the correlation decreased among those with normoglycemia and IFG (p < 0.001). Higher eAG levels were associated with older age, females, higher FPG, and lower HDL-C and triglycerides (p < 0.05). The proportion of subjects with a higher value of FPG than eAG was 46.3% in poorly controlled diabetic patients, compared with only 1.5% in normoglycemic subjects. This suggests eAG could help patients to understand their glycemic variability intuitively and healthcare providers to identify patients who might worsen in hyperglycemia control through measuring the difference between eAG and FPG.

Good adherence by physicians to treatment guidelines for type II diabetes mellitus (T2DM) could improve therapy outcome for patients. In this retrospective, cross-sectional study, we assessed physicians\' adherence to evidence-based guidelines for T2DM management in adult patients (aged ≥18 years) with either confirmed atherosclerotic cardiovascular disease (ASCVD) or those at high risk of developing ASCVD at the Thumbay Academic Health Center, United Arab Emirates (UAE).
Relevant data was obtained from patients\' medical records, assessed, and compared based on the 2018 diabetes guidelines of the American Diabetes Association and European Association for the Study of Diabetes.
A total of 218 patients (186 males and 32 females) were included in the analysis. Of these, 122 were prescribed either sodium-glucose co-transporter-2(SGLT2) inhibitors or glucagon-like peptide 1 (GLP-1) receptor agonists and 34 were prescribed both. The overall adherence to the guidelines was 56%, which was significantly influenced by body mass index (BMI), hemoglobin A1c (HbA1c) levels, and estimated average glucose (eAG).
Adherence to guidelines was significantly high when treating patients with elevated levels of HbA1c and eAG, suggesting that physicians are more likely to prescribe SGLT2 inhibitors or/and GLP-1 receptor agonists to such patients. Physicians\' adherence to guidelines was significantly correlated with patients\' BMI and the levels of HbA1c and eAG. To the best of our knowledge, this is the first study conducted on diabetes and its risk factors in UAE.

Fasting plasma glucose (FPG) and HbA1c are well-known tests for monitoring short and long-term glycemic control, respectively. Estimated average glucose (eAG) is derived from the HbA1c for expression in the same units as FPG. The present study aimed to evaluate the association between eAG and FPG values. This retrospective study was performed on 1285 patients who measured the FPG and HbA1c (capillary electrophoresis method) values on the same day. They were initially divided into 3 hemoglobin-pattern groups, normal, HbE, and high HbA2, and then these 3 groups were further subdivided into whole group, subgroup 1 (HbA1c ≤ 7%) and subgroup 2 (HbA1c >7%) for analytical comparisons. The eAG values were calculated using Nathan\'s equation. The differences, agreements, and correlations between eAG and FPG were evaluated. Good agreements and strong positive correlations between eAG and FPG values were observed in all 3 whole groups. In subgroup analysis, the degrees of agreement and correlation depended on the level of glycemic control, as all associations became stronger with better glycemic control. Additionally, the HbA1c levels and different eAG-FPG values between the normal and other groups were not significantly different in either whole group or subgroup comparisons. Our study found good agreements and strong positive correlations between eAG and FPG in all groups, indicating that high HbA2 or HbE did not affect the HbA1c levels or thus the associations between eAG and FPG. Reporting the eAG together with the HbA1c value should help improve the understanding of glycemic status in patients, leading to improved blood glucose control.

Introduction Scientific literature is scarce on the utility of estimated average glucose (eAG) from Pakistan. Hence, there is a dire need to evaluate the relationship between eAG and fasting plasma glucose (FPG), in order to enhance our understanding of eAG and its usefulness. This study aims to investigate the relationship between FPG and eAG in diabetic patients calculated using HbA1C. Materials and methods A retrospective study was conducted at the Aga Khan University, Karachi, Pakistan. The medical records of both genders in the age range of 18-60 years, presenting as outpatients at the endocrine clinic, labeled as DM, were reviewed from January 2013 to December 2019. The subjects were divided into three groups A (<130 mg/dL), B (130-179 mg/dL), and C (>180 mg/dL) based on FPG levels. A correlation was compared using Spearman\'s correlation. Box, whisker plots, and scatter plots were computed by R studio. Results After excluding those with missing values for either serum Cr, FPG, and HbA1c and sub-optimal renal function based on estimated glomerular filtration rate (eGFR) a total of 4,673 cases were analyzed. Subgroup A showed good glycemic control, whereas subgroup C showed poor glycemic control. The difference between eAG and FPG was significant (p < 0.0001). eAG values were found to be elevated than FPG values in groups A and B and almost the same in group C, whereas a moderately significant correlation with eAG and FPG in all three groups. Conclusion The correlation between eAG and FPG varies with blood glucose control and was significantly higher in the poorly controlled diabetes group. As the association between the FPG and eAG levels varies with the extent of blood glucose control, reporting eAG with HbA1c by a simple formula, at no additional cost will prove to be beneficial for clinical care.

The Estimated Average Glucose (eAG) is assumed to provide patients a better understanding of their recent average blood sugar levels comparing to HbA1c, therefore better control their glycemic levels. However, since its inception, debates on its clinical utility have been over several years leading to an unpopular laboratory and clinical practice of adoption; and there is no evidence to support or against the usefulness of eAG in real world medical practice. Data set presented in this article is related to our research paper entitled \"Usefulness of Estimated Average Glucose (eAG) in glycemic Control and Cardiovascular Risk Reduction\", available in Clinical Biochemistry [1]. In this article, we compared population lipid and glycemic controls in pediatric diabetic patients of the regional health authority (RHA) zone 1.1 in New Brunswick, Canada, before and after the eAG implementation in January 2010, and with other 7 zones that do not report the parameter. Data (7,355 HbA1c values and 2,062 LDL-c values) was extracted from all pediatric diabetic patients in the Provincial Diabetes Registry from 2008 to 2014. The proportions of patients achieving therapeutic targets (HbA1c<53 mmol/mol (7.0%) and LDL-c<2.6 mmol/L) and the distributions of HbA1c and LDL-c values pre/post the eAG implementation in RHA Zone 1.1 were assessed. Additionally, to investigate whether the glycemic and cholesterol control in pediatric diabetic patients in RHA Zone 1.1 after the implementation of eAG was better than in other zones, we also compared the medians and inter quartile ranges of HbA1c and LDL-c from different zones from 2010 to 2014.

OBJECTIVE: One of the 8 regional health authority (RHA) zones in New Brunswick, Canada has implemented eAG since 2010. We sought to evaluate the clinical outcomes of glycemic control and cardiovascular risk levels before and after the eAG implementation in this zone; and to compare the overall outcomes of this zone with other 7 zones of the province.
METHODS: Data (838,407 HbA1c values and 612,314 LDL-c values) was extracted from all adult diabetic patients in the provincial Diabetes Registry from 2008 to 2014. The Kruskal-Wallis statistic was conducted to compare the medians and inter quartile ranges of HbA1c and LDL-c from different zones. The proportion of patients achieving therapeutic targets, the distribution of HbA1c and LDL-c values pre/post the eAG implementation in RHA Zone 1.1 were assessed by Chi-square analysis.
RESULTS: The proportion of patients achieving targets in Zone 1.1 were at an intermediate level among all 8 zones and the trends of Zone 1.1 were no different than other zones. There were statistically significant differences for Zone 1.1 in the distribution of HbA1c (Z = -12.5190, P < 0.001) and LDL-c (Z = 16.4410, P < 0.001) before and after the eAG reported. The proportion of patients with HbA1c < 53 mmol/mol (7.0%) of the RHA Zone 1.1 was significantly lower after eAG reported (49.85% vs. 47.24%, P < 0.001); while the proportion of patients with LDL-c < 2.6 mmol/L showed statistically significant increase (68.56% vs. 71.90%, P < 0.001).
CONCLUSIONS: The utilization of eAG has demonstrated no significant impact on glycemic control and cardiovascular risk reduction.

BACKGROUND: Estimated average glucose (AG) is generally reported along with hemoglobin A1c measurements according to a standard calculation. Given a normal red blood cell lifetime of 120 days, serial A1c measurements at intervals <120 days are not completely independent. For short interval measurements, a change in AG (ΔAG) necessarily underestimates the change in average glucose operative during the interval (ΔG). We use a model for kinetics of HbA1c to evaluate the theoretical relationship between ΔAG and ΔG for HbA1c measurements made at intervals between 0 and 120 days.
METHODS: From any given starting point for A1c, step changes in G were simulated using model calculations to determine the extent to which A1c could change as a function of the interval of exposure. Values for ΔAG were compared to the operative ΔG as a function of the interval between A1c measurements.
RESULTS: Results of model simulations are a single graph for relationship of ΔAG to ΔG as a function of the interval between A1c measurements. ΔAG for (15, 30, 45, 60, 76, and 90) day intervals underestimated operative ΔG by (73, 51, 34, 21, 11, and 5)%, respectively.
CONCLUSIONS: Model calculations predict the relationship between changes in estimated average glucose to changes in operative glucose for serial A1c measurements made at intervals <120 days. Given that serial measurements of A1c made at short intervals are not uncommon in practice, physicians may find this information to be useful.

BACKGROUND: A model for hemoglobin A1c (HbA1c) formation was used to predict the relationship between average glucose (AG) and %HbA1c under conditions of altered red blood cell lifetime (RCL).
METHODS: Using a kinetic mass balance model for formation of HbA1c in red blood cells as a function of age (time in circulation), whole blood %HbA1c vs. glucose was calculated based on the nonlinear distribution of red blood cells as a function of age across RCL.
RESULTS: Model calculations provided a close fit to the standard relationship of estimated average glucose to %HbA1c for normal RCL (r>0.999). Results for altered RCL were calculated assuming simple time-scale compression or expansion of the distribution of red blood cells as a function of RCL. For a given %HbA1c, the operative average glucose needed to have achieved a given %HbA1c was predicted to be altered by RCL according to average glucose×RCL=constant.
CONCLUSIONS: Model calculations estimate the extent to which standard reporting of AG vs. HbA1c underestimates or overestimates AG under conditions of altered RCL. Conditions of altered RCL may often be operative in patients with certain hemoglobin variants.

This study aimed to examine the relationship between average glucose levels, assessed by continuous glucose monitoring (CGM), and HbA1c levels in pregnant women with diabetes to determine whether calculations of standard estimated average glucose (eAG) levels from HbA1c measurements are applicable to pregnant women with diabetes.
CGM data from 117 pregnant women (89 women with type 1 diabetes; 28 women with type 2 diabetes) were analysed. Average glucose levels were calculated from 5-7 day CGM profiles (mean 1275 glucose values per profile) and paired with a corresponding (±1 week) HbA1c measure. In total, 688 average glucose-HbA1c pairs were obtained across pregnancy (mean six pairs per participant). Average glucose level was used as the dependent variable in a regression model. Covariates were gestational week, study centre and HbA1c.
There was a strong association between HbA1c and average glucose values in pregnancy (coefficient 0.67 [95% CI 0.57, 0.78]), i.e. a 1% (11 mmol/mol) difference in HbA1c corresponded to a 0.67 mmol/l difference in average glucose. The random effects model that included gestational week as a curvilinear (quadratic) covariate fitted best, allowing calculation of a pregnancy-specific eAG (PeAG). This showed that an HbA1c of 8.0% (64 mmol/mol) gave a PeAG of 7.4-7.7 mmol/l (depending on gestational week), compared with a standard eAG of 10.2 mmol/l. The PeAG associated with maintaining an HbA1c level of 6.0% (42 mmol/mol) during pregnancy was between 6.4 and 6.7 mmol/l, depending on gestational week.
The HbA1c-average glucose relationship is altered by pregnancy. Routinely generated standard eAG values do not account for this difference between pregnant and non-pregnant individuals and, thus, should not be used during pregnancy. Instead, the PeAG values deduced in the current study are recommended for antenatal clinical care.

Hemoglobin is a tetramer formed of two alpha and two beta globin chains. On exposure to high levels of blood glucose, hemoglobin gets non-enzymatically glycated at different sites in the molecule. HbA1c is formed when glucose gets added on to the N-terminal valine residue of the beta chain of hemoglobin. The development of chronic vascular complications of diabetes such as retinopathy, nephropathy and cardiovascular disease is intimately linked to the level of glycemic control attained by the individual with diabetes. We report a case of convulsions and monoplegia admitted to emergency department, showing unusually high glycated hemoglobin but plasma glucose not as high. The patient was not a known diabetic and we could not find any of the other documented conditions that are known to elevate glycated hemoglobin to such disproportionately high levels. Screening for abnormal hemoglobins was negative in the patient. Oral hypoglycemic drug treatment over 3 months and withdrawal of other medications only marginally lowered glycated hemoglobin.