The National Glycohemoglobin Standardization Program: Over 20 Years of Improving Hemoglobin A1c Measurement

Interference in HbA1c measurement: a case of electropherogram shift due to hyperleukocytosis leading to the discovery of leukemic mantle cell lymphoma

HbA1c is a pivotal biomarker in diabetes management, reflecting long-term glycaemic control. HbA1c is often measured with capillary electrophoresis, which generally is a very precise technique, but there can be interference, especially in the case of haemoglobin diseases. Thus, in patients with underlying conditions, the accurate measurement of HbA1c can be challenging. We present a case of special interference in a 74-year-old female patient referred to a HbA1c test, in whom the measurement was thought to be significantly affected by hyperleukocytosis and led to an unexpected diagnosis of leukemic low-grade lymphoma. This case report highlights the underrecognized potential interference of leukocytosis in HbA1c measurement. It underscores the importance of clinical vigilance when interpreting HbA1c results in patients with underlying haematological conditions.

A high stable sample loading for analysis of adult alpha-thalassemia via the improved microarray isoelectric focusing of Hb species

The isoelectric focusing has realized various improvements, including the protocols and creation of mIEF (microcolumn isoelectric focusing) instruments with excellent sensitivity for screening of diabetes and beta thalassemia. However, the problem of manual sample loading and hydration for the mIEF limits the operational capacity for stably detecting and quantitating most abnormal hemoglobin (Hb). Herein, we provided a high stable sample loading protocol for analysis of alpha thalassemia and Hb variants. In contrast to the previous volume of 20 μl, a 100 µl blood sample solution in this protocol was optimized with mixture of 6.4-7.5 and 3-10 pH carrier ampholytes, pI markers and loaded for 30 mins IPG microcolumn hydration. The hydrated microcolumn was then automatically loaded onto the mIEF chip array to which CH3COOH and NH4OH act as anodic and cathodic solutions. Lastly, the IEF was run for 9 mins. Hb H, Barts, A1c, F, A2 and CS were simultaneously separated and focused with higher resolution and sensitivity in quantifying H and Barts as low as 0.6 and 0.5 % respectively. Accordingly, there was an enhanced stability and linearity with a rapid assay time of 45 secs per sample. Moreover, analysis showed a fitting linear relationship with conventional technology at R2 = 0.9803 for H and R2 = 0.9728 for Barts thereby indicating greater accuracy confirmed by the AUC. Hence, the developed protocol could simply be employed for high stable and throughput batch sample loading of hydration, and accurate separation and quantitation of Hb variants for alpha and beta thalassemia.

Point-of-Care HbA1c in Clinical Practice: Caveats and Considerations for Optimal Use

Hemoglobin A1c (A1C) is widely used for the diagnosis and management of diabetes. Accurate measurement of A1C is necessary for optimal clinical value. Assay standardization has markedly improved the accuracy and consistency of A1C testing. Devices to measure A1C at point of care (POC) are commercially available, allowing rapid results when the patient is seen. In this review, we describe how standardization of A1C testing was achieved, leading to high-quality results in clinical laboratories. We address the use of POC A1C testing in clinical situations and summarize the advantages and disadvantages of POC A1C testing. We emphasize the importance of considering the limitations of these devices and following correct testing procedures to ensure that accurate A1C results are obtained for optimal care of patients.

The Glucose Management Indicator: Time to Change Course?

Laboratory measurement of hemoglobin A1c (HbA1c) has, for decades, been the standard approach to monitoring glucose control in people with diabetes. Continuous glucose monitoring (CGM) is a revolutionary technology that can also aid in the monitoring of glucose control. However, there is uncertainty in how best to use CGM technology and its resulting data to improve control of glucose and prevent complications of diabetes. The glucose management indicator, or GMI, is an equation used to estimate HbA1c based on CGM mean glucose. GMI was originally proposed to simplify and aid in the interpretation of CGM data and is now provided on all standard summary reports (i.e., average glucose profiles) produced by different CGM manufacturers. This Perspective demonstrates that GMI performs poorly as an estimate of HbA1c and suggests that GMI is a concept that has outlived its usefulness, and it argues that it is preferable to use CGM mean glucose rather than converting glucose to GMI or an estimate of HbA1c. Leaving mean glucose in its raw form is simple and reinforces that glucose and HbA1c are distinct. To reduce patient and provider confusion and optimize glycemic management, mean CGM glucose, not GMI, should be used as a complement to laboratory HbA1c testing in patients using CGM systems.

Research progress on the association between glycemic variability index derived from CGM and cardiovascular disease complications

Currently, glycated hemoglobin A1c (HbA1c) has been widely used to assess the glycemic control of patients with diabetes. However, HbA1c has certain limitations in describing both short-term and long-term glycemic control. To more accurately evaluate the glycemic control of diabetes patients, the continuous glucose monitoring (CGM) technology has emerged. CGM technology can provide robust data on short-term glycemic control and introduce new monitoring parameters such as time in range, time above range, and time below range as indicators of glycemic fluctuation. These indicators are used to describe the changes in glycemic control after interventions in clinical research or treatment modifications in diabetes patient care. Recent studies both domestically and internationally have shown that these indicators are not only associated with microvascular complications of diabetes mellitus but also closely related to cardiovascular disease complications and prognosis. Therefore, this article aims to comprehensively review the association between CGM-based glycemic parameters and cardiovascular disease complications by analyzing a large number of domestic and international literature. The purpose is to provide scientific evidence and guidance for the standardized application of these indicators in clinical practice, in order to better evaluate the glycemic control of diabetes patients and prevent the occurrence of cardiovascular disease complications. This research will contribute to improving the quality of life for diabetes patients and provide important references for clinical decision-making.

Impact of haemoglobin variants on the diagnostic sensitivity of glycated haemoglobin (HbA1c) assay methodologies in sub-Saharan Africa: a laboratory-based method validation study

Introduction

the utility of glycated haemoglobin (HbA1c) for the diagnosis and monitoring of diabetes in sub-Saharan Africa is uncertain due to limited data on the performance of the available HbA1c assay methods in this population, which has a high prevalence of haemoglobin variants. We aimed to compare the diagnostic accuracy of the major HbA1c methodologies (Boronate Affinity, Capillary Electrophoresis, High Performance Liquid Chromatography, Immunoassay) in an African population, and assess the impact of the common haemoglobin variant HbAS (sickle cell trait).

Methods

whole blood samples were obtained from 182 individuals living with type 2 diabetes in Uganda. HbA1c values for each method were compared to average glucose measured over 14 days by continuous glucose monitoring (CGM). To determine concordance, the three HbA1c assay methods were compared to the capillary electrophoresis method.

Results

there was a strong correlation between CGM average glucose levels and all four HbA1c methodologies (r=0.81-0.89) which did not differ in those with and without HbAS (present in 37/182 participants). The presence of HbAS did not alter the relationship between HbA1c and CGM glucose for any assay (p for interaction >0.2 for all methods). Diagnostic accuracy for CGM average glucose thresholds of 7 and 10mmol/L was similar across methods (area under the receiver operating characteristic curve 0.80-0.84 and 0.76-0.84 respectively). The maximum bias between the HbA1c assay methodologies was 2 mmol/mol (2.07%).

Conclusion

all major HbA1c technologies offer accurate and comparable HbA1c measurement even in this population with high prevalence of haemoglobin variants.

Emerging biosensor probes for glycated hemoglobin (HbA1c) detection

Glycated hemoglobin (HbA1c), originating from the non-enzymatic glycosylation of βVal1 residues in hemoglobin (Hb), is an essential biomarker indicating average blood glucose levels over a period of 2 to 3 months without external environmental disturbances, thereby serving as the gold standard in the management of diabetes instead of blood glucose testing. The emergence of HbA1c biosensors presents affordable, readily available options for glycemic monitoring, offering significant benefits to small-scale laboratories and clinics. Utilizing nanomaterials coupled with high-specificity probes as integral components for recognition, labeling, and signal transduction, these sensors demonstrate exceptional sensitivity and selectivity in HbA1c detection. This review mainly focuses on the emerging probes and strategies integral to HbA1c sensor development. We discussed the advantages and limitations of various probes in sensor construction as well as recent advances in diverse sensing strategies for HbA1c measurement and their potential clinical applications, highlighting the critical gaps in current technologies and future needs in this evolving field.

Harmonization of four biomarkers across nine nationally representative studies of older persons

INTRODUCTION

A growing number of international population surveys have included measurement of biomarkers, but differ in the type of specimens collected, sample processing procedures, shipment protocols, and laboratory assay platforms. The purpose of this study is to harmonize biomarker data from nine nationally representative studies of people 50 years of age and over by adjusting for assay platforms and type of specimens for total cholesterol (total-C), high-density lipoprotein cholesterol (HDL-C), glycosylated hemoglobin (HbA1c), and C-reactive protein (CRP).

METHODS

Sets of 24 identical serum, plasma, whole blood, and dried blood spot harmonization samples with known analyte levels were generated at a reference laboratory, shipped at -80°C to the respective study laboratories, and subsequently assayed following the study laboratory's protocol. Both original and harmonized study data were used to calculate mean values and at-risk prevalence.

RESULTS

The correlation coefficients between the biomarker values of the harmonization samples obtained by the study laboratories and the reference laboratory were 0.99 or above for all analytes and laboratories, indicating the high quality of assays at all laboratories. However, using the harmonized data from each study, there were significant differences in the mean values and country ranking of the prevalence of at-risk levels of these four biomarkers.

CONCLUSIONS

While the biomarker data from the different study laboratories were highly correlated, indicating very high correlation of rank order of specimens, absolute values did vary significantly. This can have a major impact on assessment of international differences in estimates of risks for chronic morbidity and mortality.

Quantification of Glycated Hemoglobin in Total Hemoglobin by a Simultaneous Dual-Signal Acquisition Approach

The glycated hemoglobin (HbA1c) level, which is defined as the ratio of HbA1c to total hemoglobin (tHb, including glycated and unglycated hemoglobin), is considered one of the preferred indicators for diabetes monitoring. Generally, assessment of the HbA1c level requires separate determination of tHb and HbA1c concentrations after a complex separation step. This undoubtedly increases the cost of the assay, and the loss or degradation of HbA1c during the separation process results in a decrease in the accuracy of the assay. Therefore, this study explored a dual-signal acquisition method for the one-step simultaneous evaluation of tHb and HbA1c. Quantification of tHb: graphene adsorbed carbon quantum dots and methylene blue were utilized as the substrate material and linked to the antibody. tHb was captured on the substrate by the antibody. The unique heme group on tHb catalyzed the production of •OH from H2O2 to degrade methylene blue on the substrate, and a quantitative relationship between the tHb concentration and the methylene blue oxidation current signal was constructed. Quantification of HbA1c: complex labels with HbA1c recognition were made of ZIF-8-ferrocene-gold nanoparticles-mercaptophenylboronic acid. The specific recognition of the boronic acid bond with the unique cis-diol structure of HbA1c establishes a quantitative relationship between the oxidation current of the label-loaded ferrocene and the concentration of HbA1c. Thus, the HbA1c level can be assessed with only one signal readout. The sensor exhibited extensive detection ranges (0.200-600 ng/mL for tHb and 0.100-300 ng/mL for HbA1c) and low detection limits (4.00 × 10-3 ng/mL for tHb and 1.03 × 10-2 ng/mL for HbA1c).

Evolution of LC-MS/MS in clinical laboratories

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) has attracted significant attention in clinical practice owing to its numerous advantages. However, the widespread adoption of this technique is hindered by certain limitations, such as inappropriate analyte selection, low levels of automation, and a lack of specific reference intervals and quality control programs. This review comprehensively summarizes the current challenges associated with LC-MS/MS and proposes potential resolutions. The principle of utility should guide the selection of biomarkers, prioritizing their practical value over sheer quantity. To achieve full-process automation, methodological innovation is crucial for developing high-throughput equipment. Establishing reference intervals for mass spectrometry-based assays across multiple centers and diverse populations is essential for accurate result interpretation. Additionally, the development of commercial quality control materials assumes pivotal importance in ensuring assay reliability and reproducibility. Harmonization and standardization efforts should focus on the development of reference methods and materials for the clinical use of LC-MS/MS. In the future, commercial assay kits and laboratory-developed tests (LDTs) are expected to coexist in clinical laboratories, each offering distinct advantages. The collaborative efforts of diverse professionals is vital for addressing the challenges associated with the clinical application of LC-MS/MS. The anticipated advancements include simplification, increased automation, intelligence, and the standardization of LC-MS/MS, ultimately facilitating its seamless integration into clinical routines for both technicians and clinicians.

Estimating Glycemia From HbA1c and CGM: Analysis of Accuracy and Sources of Discrepancy

OBJECTIVE

To examine the accuracy of different periods of continuous glucose monitoring (CGM), hemoglobin A1c (HbA1c), and their combination for estimating mean glycemia over 90 days (AG90).

RESEARCH DESIGN AND METHODS

We retrospectively studied 985 CGM periods of 90 days with <10% missing data from 315 adults (86% of whom had type 1 diabetes) with paired HbA1c measurements. The impact of mean red blood cell age as a proxy for nonglycemic effects on HbA1c was estimated using published theoretical models and in comparison with empirical data. Given the lack of a gold standard measurement for AG90, we applied correction methods to generate a reference (eAG90) that we used to assess accuracy for HbA1c and CGM.

RESULTS

Using 14 days of CGM at the end of the 90-day period resulted in a mean absolute error (95th percentile) of 14 (34) mg/dL when compared with eAG90. Nonglycemic effects on HbA1c led to a mean absolute error for average glucose calculated from HbA1c of 12 (29) mg/dL. Combining 14 days of CGM with HbA1c reduced the error to 10 (26) mg/dL. Mismatches between CGM and HbA1c >40 mg/dL occurred more than 5% of the time.

CONCLUSIONS

The accuracy of estimates of eAG90 from limited periods of CGM can be improved by averaging with an HbA1c-based estimate or extending the monitoring period beyond ∼26 days. Large mismatches between eAG90 estimated from CGM and HbA1c are not unusual and may persist due to stable nonglycemic factors.

Review on the screening of urine glucose for early diagnosis of type 2 diabetes mellitus in school children and adolescents with obesity in Hong Kong

OBJECTIVES

Obesity and type 2 diabetes mellitus (T2DM) are growing health concerns. Since 2005, Student Health Service (SHS) and Hong Kong Paediatric Society formulated a protocol on urine glucose screening (UGS) for early diagnosis of T2DM in students with obesity in Hong Kong. This study reviews students with T2DM captured by this screening program and compare the data with the Hong Kong Children Diabetes Registry (HKCDR) database, to see if the UGS program facilitates early diagnosis of T2DM.

METHODS

Students between the ages of 10-18 years old with age- and sex-specific body mass index (BMI) >97th percentile who attended SHS between the school years from 2005/06 to 2017/18 were recruited for UGS. Those tested positive for random urine glucose underwent diagnostic testing for T2DM according to ADA guidelines. Demographic data and investigatory results from UGS and HKCDR within the same time period were compared.

RESULTS

A total of 216,526 students completed UGS in the said period; 415 (0.19 %) students were tested positive for urine glucose of which 121 students were diagnosed with T2DM. UGS picked up 23 % of the newly diagnosed T2DM cases. When compared to the HKCDR database, students diagnosed via UGS were significantly younger, less obese, and had fewer diabetic related complications. The negative predictive value of UGS is high and can effectively rule out T2DM.

CONCLUSIONS

Urine glucose screening is an inexpensive and simple test that allows for early diagnosis of T2DM among obese school students. Other methods including POCT HbA1c can be explored to improve program effectiveness.

Racial differences in measures of glycemia in the Vitamin D and Type 2 Diabetes (D2d) Study: a secondary analysis of a randomized trial

INTRODUCTION

Understanding how race may influence the association between A1c and glycemia can improve diabetes screening. We sought to determine whether, for a given A1c level, glucose levels during an oral glucose tolerance test (OGTT) differed by race.

RESEARCH DESIGN AND METHODS

From data collected at 22 US clinical sites, we conducted a cross-sectional study of concurrently measured A1c and OGTT and observational longitudinal follow-up of the subset with high-risk pre-diabetes. Numerical integration methods were used to calculate area under the glycemic curve (AUCglu) during OGTT and least squares regression model to estimate A1c for a given AUCglu by race, controlling for potential confounders.

RESULTS

1016 black, 2658 white, and 193 Asian persons at risk of diabetes were included in cross-sectional analysis. Of these, 2154 with high-risk pre-diabetes were followed for 2.5 years. For a given A1c level, AUCglu was lower in black versus white participants. After adjustment for potential confounders, A1c levels for a given AUCglu quintile were 0.15-0.20 and 0.02-0.19 percentage points higher in black and Asian compared with white participants, respectively (p<0.05). In longitudinal analyses, black participants were more likely to be diagnosed with diabetes by A1c than white participants (28% vs 10%, respectively; p<0.01). Black and Asian participants were less likely to be diagnosed by fasting glucose than white participants (16% vs 15% vs 37%, respectively; p<0.05). Black participants with A1c levels in the lower-level quintiles had greater increase in A1c over time compared with white participants.

CONCLUSIONS

Use of additional testing beyond A1c to screen for diabetes may better stratify diabetes risk in the diverse US population.

The Role of Systemic Family Psychotherapy in Glycemic Control for Children with Type 1 Diabetes

(1) Background: Family factors play an important role in the management of diabetes, establishing a relationship between conflicts and non-adherence to therapy. High values of HbA1c are involved in specific complications of the disease (retinopathy, nephropathy, neuropathy, ketoacidosis). This study aimed to determine the role of systemic family psychotherapeutic interventions in increasing the quality of parent-child/adolescent relationships and in optimizing the child's glycemic control. (2) Methods: In this prospective observational study, 64 parents of children and adolescents with type 1 diabetes were evaluated regarding their relationship with their children, using the Child-Parent Relationship Scale-Short Form (CPRS-short form). The children were divided into three groups: one participated for 6 months in systemic family psychotherapy with children and their parents (FT), the second group participated in individual psychotherapy (IT), and the control group (CG) received no intervention. HbA1c values were recorded before and after the interventions. (3) Results: HbA1c means decreased significantly after the family psychotherapy program. The scores on closeness in the family therapy group increased significantly, and the scores on conflict decreased significantly after the intervention, compared with IT and CG. (4) Conclusions: Systemic family psychotherapy produces better results in disease management and in strengthening parent-child relationships.

Diagnosis and screening of abnormal hemoglobins

Hemoglobin (Hb) abnormalities, such as thalassemia and structural Hb variants, are among the most prevalent inherited diseases and are associated with significant mortality and morbidity worldwide. However, there were not comprehensive reviews focusing on different clinical analytical techniques, research methods and artificial intelligence (AI) used in clinical screening and research on hemoglobinopathies. Hence the review offers a comprehensive summary of recent advancements and breakthroughs in the detection of aberrant Hbs, research methods and AI uses as well as the present restrictions anddifficulties in hemoglobinopathies. Recent advances in cation exchange high performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE), isoelectric focusing (IEF), flow cytometry, mass spectrometry (MS) and polymerase chain reaction (PCR) etc have allowed for the definitive detection by using advanced AIand portable point of care tests (POCT) integrating with smartphone microscopic classification, machine learning (ML) model, complete blood counts (CBC), imaging-based method, speedy immunoassay, and electrochemical-, microfluidic- and sensing-related platforms. In addition, to confirm and validate unidentified and novel Hbs, highly specialized genetic based techniques like PCR, reverse transcribed (RT)-PCR, DNA microarray, sequencing of genomic DNA, and sequencing of RT-PCR amplified globin cDNA of the gene of interest have been used. Hence, adequate utilization and improvement of available diagnostic and screening technologies are important for the control and management of hemoglobinopathies.

Defining allowable total error limits in the clinical laboratory

Allowable total error (ATE) are performance specification limits predefined for a variety of laboratory analytes. These limits define the maximum amount of error that is allowed for an assay when judging acceptability of a new assay during method verification/validation, evaluating patient or instrument comparison data, or in designing a quality control strategy. There are several widely available resources and models that can serve as a guide in selecting ATE. They may be based on legal requirements or set by providers of proficiency testing (PT) and external quality assessment schemes (EQAS). ATE can be also determined by professional expert groups or be based on biological variation of an analyte. Because there are several resources to choose from, there have been several attempts in reaching consensus on which ATE resource should be given preference. This chapter reviews several of these resources in more detail and discusses the difference between allowable total error (ATE) and observed total analytical error (TAE).

Prediabetes in children and adolescents: An updated review

Prediabetes, the precursor of type 2 diabetes mellitus, is an intermediate stage between normal glucose homeostasis and overt diabetes. This asymptomatic metabolic state is increasingly prevalent in pediatric population and is very difficult to detect without appropriate screening. Studies have shown that a certain proportion of children with prediabetes will develop diabetes in a few years. Even more alarming is the evidence that youth-onset diabetes has a more aggressive clinical course with progressive beta-cell decline and accelerated end-organ damage. Despite its importance, several aspects involving prediabetes in childhood are disputed or unknown. This review presents the latest insights into this challenging entity and outlines a simplified screening approach to aid clinical practice. In summary, childhood prediabetes is an important clinical condition indicating the need for proper screening and timely intervention.

A Longitudinal Study of Plasma Glycated Albumin across Pregnancy and Associations with Maternal Characteristics and Cardiometabolic Biomarkers

BACKGROUND

Glycated albumin (GA) has recently been proposed as a screening marker for diabetes among non-pregnant individuals. However, data on GA during pregnancy are sparse and lacking among women of diverse race/ethnicity. We investigated longitudinal concentrations of GA among multiracial pregnant women in the National Institute of Child Health and Human Development (NICHD) Fetal Growth Studies-Singletons.

METHODS

We quantified GA and cardiometabolic biomarkers using longitudinal plasma samples collected at 10 to 14, 15 to 26 (fasting), 23 to 31, and 33 to 39 gestational weeks from 214 pregnant women without gestational diabetes. We examined the distribution of GA across pregnancy and its association with participants' characteristics including race/ethnicity, pre-pregnancy body mass index (ppBMI), and selected cardiometabolic biomarkers. GA trajectories were estimated using a latent class approach.

RESULTS

Medians (interquartile range) of GA concentrations were 12.1% (10.6%-13.4%), 12.5% (10.7%-13.8%), 12.4% (10.9%-13.5%), and 11.5% (10.4%-12.5%) at 10 to 14, 15 to 26, 23 to 31, and 33 to 39 weeks, respectively. There were no significant differences in the pattern among different race/ethnic groups (P > 0.53). A minority of women exhibited a GA trajectory characterized by a high concentration of GA at 15 to 26 weeks. GA concentrations were inversely related to ppBMI and plasma low-density lipoprotein and triglyceride concentrations, but were not significantly related to hemoglobin A1c, fasting insulin, or glucose over pregnancy.

CONCLUSIONS

In this study of individuals who were normoglycemic before pregnancy, plasma GA concentrations stayed relatively constant over pregnancy, decreasing only in late pregnancy. GA concentrations were inversely related to ppBMI and suboptimal lipid profiles, but did not appear to be a sensitive marker for glucose metabolism in pregnancy.

Evaluation of the Premier Hb9210 instrument for HbA1c determination

Background: Glycated hemoglobin measurements are a valuable tool for long-term blood glucose monitoring and the diagnosis of diabetes. Its widespread use has been made possible due to the development of new analytical methods with improved performances and standardization with reference materials. The aim of the present study was to evaluate the Trinity Biotech Premier Hb9210 analyzer for the measurement of HbA1c.Methods: The precision was assessed using the CLSI EP-15A3 and EP-10A3 protocols. The latter was also used to investigate linearity, carryover, and linear drift. The comparison study was performed between Premier Hb910 and Tosoh HLC-723 G8 through Passing-Bablok regression and the Bland-Altman plot. The Fleiss Kappa index was used to assess the degree of agreement. The interference of Hb variants was investigated using samples with Hb variants S, C, D, E, J, and Seville.Results: Within-run and between-run imprecision fell between 0.37% and 1.16%. No statistically significant nonlinearity, carry-over, and/or drift were observed. The resulting regression line of the Passing-Bablok analysis was y = 0.00 + 1.00x. The Pearson correlation coefficient was 0.997. In the Bland-Altman plot, the relative bias was 0.01%. The overall Fleiss Kappa index was 0.9. No interference from hemoglobin variants was observed.Conclusion: The Premier Hb9210 demonstrated a high degree of automation, reproducibility, good agreement, minimal carry-over effect, and excellent linearity across the wide range of HbA1c levels commonly found in diabetic patients and was not influenced by Hb variants.

Real-World Hemoglobin A1c Changes, Prescribing Provider Types, and Medication Dose Among Patients with Type 2 Diabetes Mellitus Initiating Treatment with Oral Semaglutide

INTRODUCTION

Given the lack of real-world data on oral semaglutide use outside clinical trials, the purpose of this study was to describe dose, prescriber specialty, and change in hemoglobin A1c (HbA1c) after 6 months of oral semaglutide treatment for patients with type 2 diabetes mellitus (T2DM).

METHODS

This was a retrospective study among adult patients with T2DM with ≥ 1 claim for oral semaglutide between November 1, 2019`1-June 30, 2020. Patients had continuous health plan enrollment ≥ 12 months prior to (pre-index) and ≥ 6 months following (post-index) the date of the first oral semaglutide claim (index). Dose at initiation and specialty of the prescribing provider were captured. Change in HbA1c between the last post- and pre-index HbA1c measurement was calculated. Patients were stratified by pre-index HbA1c ≥ 9% (poorly controlled) and HbA1c < 9%.

RESULTS

A total of 744 HbA1c < 9% and 268 poorly controlled patients were included in the study. Most patients had an initial oral semaglutide dose of 7 mg (49.3%) or 3 mg (42.9%), prescribed most frequently by a primary care provider (27.8%). Mean HbA1c reduction was 0.8% (p < 0.001). Patients with poorly controlled T2DM had greater HbA1c reductions than patients with HbA1c < 9% (2.0% versus 0.4%, p < 0.001). Patients persistent with oral semaglutide (≥ 90 days continuous treatment) had a mean HbA1c reduction of 0.9% (p < 0.001); persistent patients with poorly controlled T2DM had a mean reduction of 2.5%.

CONCLUSIONS

Patients with T2DM in this study experienced significant reductions in HbA1c within 6 months following initiation of oral semaglutide. Patients with a higher starting HbA1c experienced greater HbA1c reductions. The initial dose of oral semaglutide was higher than prescribing instructions indicated for more than half of the study patients.

Clinical performance and health equity implications of the American Diabetes Association's 2023 screening recommendation for prediabetes and diabetes

Introduction

The American Diabetes Association (ADA) recommends screening for prediabetes and diabetes (dysglycemia) starting at age 35, or younger than 35 years among adults with overweight or obesity and other risk factors. Diabetes risk differs by sex, race, and ethnicity, but performance of the recommendation in these sociodemographic subgroups is unknown.

Methods

Nationally representative data from the National Health and Nutrition Examination Surveys (2015-March 2020) were analyzed from 5,287 nonpregnant US adults without diagnosed diabetes. Screening eligibility was based on age, measured body mass index, and the presence of diabetes risk factors. Dysglycemia was defined by fasting plasma glucose ≥100mg/dL (≥5.6 mmol/L) or haemoglobin A1c ≥5.7% (≥39mmol/mol). The sensitivity, specificity, and predictive values of the ADA screening criteria were examined by sex, race, and ethnicity.

Results

An estimated 83.1% (95% CI=81.2-84.7) of US adults were eligible for screening according to the 2023 ADA recommendation. Overall, ADA's screening criteria exhibited high sensitivity [95.0% (95% CI=92.7-96.6)] and low specificity [27.1% (95% CI=24.5-29.9)], which did not differ by race or ethnicity. Sensitivity was higher among women [97.8% (95% CI=96.6-98.6)] than men [92.4% (95% CI=88.3-95.1)]. Racial and ethnic differences in sensitivity and specificity among men were statistically significant (P=0.04 and P=0.02, respectively). Among women, guideline performance did not differ by race and ethnicity.

Discussion

The ADA screening criteria exhibited high sensitivity for all groups and was marginally higher in women than men. Racial and ethnic differences in guideline performance among men were small and unlikely to have a significant impact on health equity. Future research could examine adoption of this recommendation in practice and examine its effects on treatment and clinical outcomes by sex, race, and ethnicity.

Screening for Turner syndrome-associated hyperglycemia: Evaluating hemoglobin A1c and fasting blood glucose

INTRODUCTION

Individuals with Turner syndrome (TS) are at increased risk of developing diabetes mellitus (DM). Currently, annual DM screening with hemoglobin A1c (HbA1c) with or without fasting blood glucose (FBG) is recommended starting at age 10. However, the optimal DM screening for individuals with TS is not known. The purpose of this study was to evaluate the correlation between HbA1c, FBG, and the 2-hour oral glucose tolerance test (OGTT). A second goal was to query whether optimal HbA1c and fasting (FBG) cut points for TS-associated DM and impaired glucose tolerance (IGT), as defined by the OGTT 2-hour blood glucose (BG), might differ from those for the general population.

METHODS

Individuals with TS ≥ age 10 from the TS: Genotype Phenotype study in the National Institute of Child Health and Human Development's Data and Specimen Hub (DASH) who had 2-hour OGTT BG, HbA1c, and FBG were included. Correlations between HbA1c, FBG, and 2-hour OGTT BG were evaluated. Areas under the receiver operative characteristic (ROC-AUC) curves were generated. Optimal cut points for predicting TS-associated IGT (2-hour BG ≥ 7.77 mmol/L ) and DM 2-hour BG ≥11.10 mmol/L) were determined.

RESULTS

348 individuals had complete data (2-hour OGTT BG < 7.77 mmol/L, n = 239; TS-associated IGT, n = 79; DM, n = 30). ROC-AUC was poor for HbA1c to predict IGT (0.57, 0.49-0.65) but better for DM (0.81, 0.71-0.90). ROC-AUC was also poor for FBG to predict IGT (0.63, 0.56-0.70) but better for DM (0.85, 0.77-0.93). At a cut point of 38 mmol/mol (5.6%), HbA1c had 67% sensitivity (95% CI: 47-83%) and 86% specificity (95% CI: 82-90%) for identifying TS-associated DM defined by 2-hour OGTT BG.

DISCUSSION/CONCLUSIONS

The correlation of HbA1c and 2-hour OGTT BG are lower in TS than other published studies regarding type 2 DM. HbA1c is fairly specific for DM in TS but lacks sensitivity especially at currently utilized levels. Future research should focus on characterizing individuals with TS whose glycemic status is discordant, as this may provide additional insights into the pathophysiology of glucose metabolism in TS. Longitudinal assessement of glycemia as it relates to micro- and macrovascular complications in individuals with TS will further inform DM screening in this population.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association for Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (HbA1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of HbA1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Do patients with prediabetes managed with metformin achieve better glycaemic control? A national study using primary care medical records

AIMS

To estimate the effectiveness of metformin on glycaemic parameters among participants with incident prediabetes attending Australian general practices.

METHODS

This retrospective cohort study used electronic health records of regular participants (3+ visits in two consecutive years) attending 383 Australian general practices (MedicineInsight). Participants with 'incident' prediabetes (newly recorded diagnosis between 2012 and 2017) and their glycaemic parameters (haemoglobin A1c [HbA1c] or fasting blood glucose [FBG]) at 6-, 12-, and 18-24 months post diagnosis (unexposed) or post-management with metformin (treatment) were identified from the database. We estimated the average treatment effect (ATE) of metformin management on glycaemic parameters using both linear regression and augmented inverse probability weighting.

RESULTS

Of the 4770 investigated participants with 'incident' prediabetes, 10.2% were managed with metformin. Participants on metformin had higher HbA1c levels at the baseline than those unexposed (mean 45 mmol/mol [6.2%] and 41 mmol/mol [5.9%], respectively), but no differences were observed at 6-12 months (mmol/mol ATE 0.0, 95% CI -0.4; 0.7) or 12-18 months (ATE -0.3, 95% CI -1.2; 0.3). However, participants on metformin had lower mean HbA1c mmol/mol at 18-24 months (ATE -1.1, 95% CI -2.0; 0.1) than those unexposed. Consistent results were observed for FBG (ATE at 6-12 months -0.14 [95% CI -0.25; -0.04], 12-18 months 0.02 [95% CI -0.08; 0.13] and 18-24 months -0.07 [95% CI -0.25; 0.12]).

CONCLUSION

The higher HbA1c and FBG baseline levels among participants with 'incident' prediabetes managed with metformin improved after 6-12 months of starting pharmacological management, and the effect persisted for up to 24 months. Management with metformin could prevent further deterioration of glycaemic levels.

Explainable machine learning framework to predict personalized physiological aging

Attaining personalized healthy aging requires accurate monitoring of physiological changes and identifying subclinical markers that predict accelerated or delayed aging. Classic biostatistical methods most rely on supervised variables to estimate physiological aging and do not capture the full complexity of inter-parameter interactions. Machine learning (ML) is promising, but its black box nature eludes direct understanding, substantially limiting physician confidence and clinical usage. Using a broad population dataset from the National Health and Nutrition Examination Survey (NHANES) study including routine biological variables and after selection of XGBoost as the most appropriate algorithm, we created an innovative explainable ML framework to determine a Personalized physiological age (PPA). PPA predicted both chronic disease and mortality independently of chronological age. Twenty-six variables were sufficient to predict PPA. Using SHapley Additive exPlanations (SHAP), we implemented a precise quantitative associated metric for each variable explaining physiological (i.e., accelerated or delayed) deviations from age-specific normative data. Among the variables, glycated hemoglobin (HbA1c) displays a major relative weight in the estimation of PPA. Finally, clustering profiles of identical contextualized explanations reveal different aging trajectories opening opportunities to specific clinical follow-up. These data show that PPA is a robust, quantitative and explainable ML-based metric that monitors personalized health status. Our approach also provides a complete framework applicable to different datasets or variables, allowing precision physiological age estimation.

Guidelines and Recommendations for Laboratory Analysis in the Diagnosis and Management of Diabetes Mellitus

BACKGROUND

Numerous laboratory tests are used in the diagnosis and management of diabetes mellitus. The quality of the scientific evidence supporting the use of these assays varies substantially.

APPROACH

An expert committee compiled evidence-based recommendations for laboratory analysis in screening, diagnosis, or monitoring of diabetes. The overall quality of the evidence and the strength of the recommendations were evaluated. The draft consensus recommendations were evaluated by invited reviewers and presented for public comment. Suggestions were incorporated as deemed appropriate by the authors (see Acknowledgments). The guidelines were reviewed by the Evidence Based Laboratory Medicine Committee and the Board of Directors of the American Association of Clinical Chemistry and by the Professional Practice Committee of the American Diabetes Association.

CONTENT

Diabetes can be diagnosed by demonstrating increased concentrations of glucose in venous plasma or increased hemoglobin A1c (Hb A1c) in the blood. Glycemic control is monitored by the people with diabetes measuring their own blood glucose with meters and/or with continuous interstitial glucose monitoring (CGM) devices and also by laboratory analysis of Hb A1c. The potential roles of noninvasive glucose monitoring, genetic testing, and measurement of ketones, autoantibodies, urine albumin, insulin, proinsulin, and C-peptide are addressed.

SUMMARY

The guidelines provide specific recommendations based on published data or derived from expert consensus. Several analytes are found to have minimal clinical value at the present time, and measurement of them is not recommended.

Screening for Prediabetes and Diabetes: Clinical Performance and Implications for Health Equity

INTRODUCTION

In 2021, the U.S. Preventive Services Task Force (USPSTF) recommended prediabetes and diabetes screening for asymptomatic adults aged 35-70 years with overweight/obesity, lowering the age from 40 years in its 2015 recommendation. The USPSTF suggested considering earlier screening in racial and ethnic groups with high diabetes risk at younger ages or lower BMI. This study examined the clinical performance of these USPSTF screening recommendations as well as alternative age and BMI cutoffs in the U.S. adult population overall, and separately by race and ethnicity.

METHODS

Nationally representative data were collected from 3,243 nonpregnant adults without diagnosed diabetes in January 2017-March 2020 and analyzed from 2021 to 2022. Screening eligibility was based on age and measured BMI. Collectively, prediabetes and undiagnosed diabetes were defined by fasting plasma glucose ≥100 mg/dL or hemoglobin A1c ≥5.7%. The sensitivity, specificity, and predictive values of alternate screening criteria were examined overall, and by race and ethnicity.

RESULTS

The 2021 criteria exhibited marginally higher sensitivity (58.6%, 95% CI=55.5, 61.6 vs 52.9%, 95% CI=49.7, 56.0) and lower specificity (69.3%, 95% CI=65.7, 72.2 vs 76.4%, 95% CI=73.3, 79.2) than the 2015 criteria overall, and within each racial and ethnic group. Screening at lower age and BMI thresholds resulted in even greater sensitivity and lower specificity, especially among Hispanic, non-Hispanic Black, and Asian adults. Screening all adults aged 35-70 years regardless of BMI yielded the most equitable performance across all racial and ethnic groups.

CONCLUSIONS

The 2021 USPSTF screening criteria will identify more adults with prediabetes and diabetes in all racial and ethnic groups than the 2015 criteria. Screening all adults aged 35-70 years exhibited even higher sensitivity and performed most similarly by race and ethnicity, which may further improve early detection of prediabetes and diabetes in diverse populations.

Using point-of-care HbA1c to facilitate the identification of diabetes and abnormal glucose regulation in primary healthcare settings

Background

Glycated hemoglobin A1c (HbA1c) is a critical index for the diagnosis and glycemic control evaluation of diabetes. However, a standardized method for HbA1c measurement is unaffordable and unavailable among the Chinese population in low-resource rural settings. Point-of-care (POC) HbA1c testing is convenient and inexpensive, but its performance remains to be elucidated.

Objective

To investigate the value of POC HbA1c for identifying diabetes and abnormal glucose regulation (AGR) in the resource-limited Chinese population.

Methods

Participants were recruited from 6 Township Health Centers in Hunan Province. Samples for POC HbA1c, venous HbA1c, fasting plasma glucose, and 2 h-plasma glucose were obtained after physical examination. The oral glucose tolerance test was performed as the gold standard for diagnosis. The diagnostic capacities of the POC HbA1c measurement in predicting undiagnosed diabetes and AGR were evaluated.

Results

Among 388 participants, 274 (70.6%) normoglycemic controls, 63 (16.2%) prediabetes patients, and 51 (13.1%) diabetes patients were identified with oral glucose tolerance test (OGTT). Meanwhile, among 97 participants who underwent two HbA1c detection methods simultaneously, a positive correlation was found between POC HbA1c and standardized HbA1c (r = 0.75, P < 0.001). No notable systematic difference was observed from the Bland-Altman Plots. The POC HbA1c cutoff values were 5.95 and 5.25%, which efficiently identified diabetes (AUC 0.92) and AGR (AUC 0.89), respectively.

Conclusions

The alternative POC HbA1c test efficiently discriminated AGR and diabetes from normoglycemia, especially among the Chinese population in primary healthcare settings.

Controllable preparation of silver-doped hollow carbon spheres and its application as electrochemical probes for determination of glycated hemoglobin

Silver-doped hollow carbon spheres (Ag@HCS) were firstly introduced as electrochemical probes for glycated hemoglobin (HbA_1c) sensing at a molecularly imprinted polymer (MIP)-based carbon cloth (CC) electrode. Herein, Ag@HCS was prepared using one-pot polymerization of resorcinol and formaldehyde with AgNO₃ on the SiO₂ template, subsequent carbonization, and template removal. Furthermore, poly-aminophenylboronic acid (PABA) as the MIP film was used as a sensing platform for recognition of HbA_1c, which captured the Ag@HCS probe by binding of HbA_1c with aptamer modified on the probe surface. Due to regular geometry, large specific surface area, superior electrical conductivity, and highly-dispersed Ag, the prepared Ag@HCS probe provided an amplified electrochemical signal based on the Ag oxidation. By use of the sandwich-type electrochemical sensor, the ultrahigh sensitivity of 4.365 μA (μg mL^-1)^-1 cm^-2 and a wide detection range of 0.8-78.4 μg mL^-1 for HbA_1c detection with a low detection limit of 0.35 μg mL^-1 were obtained. Excellent selectivity was obtained due to the specific binding between HbA_1c and PABA-based MIP film. The fabricated electrochemical sensing platform was also implemented successfully for the determination of HbA_1c concentrations in the serum of healthy individuals.

Evaluation of local hemoglobinopathy prevalence and promotion of accurate hemoglobin A1c testing using historical data retrieval

OBJECTIVES

Heterozygous hemoglobin variants are known to cause method- and variant-specific interference with hemoglobin A1c (HbA1c) quantitation. Less attention has been paid to the role of other hemoglobin variants in confounding HbA1c testing. Here we evaluated the frequency with which enzymatic (ENZ) and immunoassay (IA) HbA1c quantitation methods, i.e., those unable to routinely detect the presence of hemoglobin variants, were used within our healthcare system for HbA1c analysis in patients with elevated fetal hemoglobin as well as compound heterozygous and homozygous variants.

DESIGN & METHODS

This analysis was enabled by automated review of HbA1c result history, implemented to promote detection of variants prior to HbA1c result reporting.

RESULTS

During a 54-week period, 319,290 HbA1c analyses were performed. We observed 110 unique patient cases (0.03% problem identification rate) in which HbA1c testing was ordered in the presence of either a homozygous or compound heterozygous hemoglobin variant or elevated hemoglobin F beyond the tolerance of the method. Among the 110 cases identified, 55 (50%) showed a compound heterozygous or homozygous hemoglobin variant while 55 (50%) showed elevated hemoglobin F. Of those cases involving a compound heterozygous or homozygous variant, 8/55 (15%) involved patients who had one or more ENZ or IA HbA1c results reported previously within our system. Of the 55 total compound heterozygous or homozygous variants identified, 37 (67%) were hemoglobin E, 10 (18%) hemoglobin S/C, 4 (7%) hemoglobin S, 2 (4%) hemoglobin C, 1 (2%) hemoglobin Camden, and 1 (2%) unidentified variant.

CONCLUSIONS

Exclusive use of methods unable to routinely detect the presence of hemoglobin variants may lead to reporting of HbA1c results that are not clinically meaningful.

Protein glycation in diabetes mellitus

Diabetes mellitus is the ninth leading cause of mortality worldwide. It is a complex disease that manifests as chronic hyperglycemia. Glucose exposure causes biochemical changes at the proteome level as reflected in accumulation of glycated proteins. A prominent example is hemoglobin A1c (HbA1c), a glycated protein widely accepted as a diabetic indicator. Another emerging biomarker is glycated albumin which has demonstrated utility in situations where HbA1c cannot be used. Other proteins undergo glycation as well thus impacting cellular function, transport and immune response. Accordingly, these glycated counterparts may serve as predictors for diabetic complications and thus warrant further inquiry. Fortunately, modern proteomics has provided unique analytic capability to enable improved and more comprehensive exploration of glycating agents and glycated proteins. This review broadly covers topics from epidemiology of diabetes to modern analytical tools such as mass spectrometry to facilitate a better understanding of diabetes pathophysiology. This serves as an attempt to connect clinically relevant questions with findings of recent proteomic studies to suggest future avenues of diabetes research.

Undefilled blood tube containing EDTA: Is it an inappropriate sample for HbA1c assay?

Introduction

Blood samples having inappropriate volume are a substantial part of preanalytical errors. Inadequate sample volume for glycated haemoglobin (HbA1c) test may be a common problem of patients with diabetes mellitus having vascular changes. In this study, we compared HbA1c concentrations of underfilled and appropriately filled blood collection tubes.

Materials and methods

To compare HbA1c concentrations, blood samples were collected into 2 mL tubes containing K3-EDTA from 109 subjects. Two blood samples (underfilled and appropriately filled) were drawn from a patient by the same personnel and materials. HbA1c measurements were assayed on a Cobas 6000 analyser module c 501 (Roche Diagnostics, Mannheim, Germany). The HbA1c% results were compared by t-test and Wilcoxon's signed-rank statistical methods (SPSS Inc., Chicago, USA). Bias analysis was performed using Microsoft Excel 4.0.

Results

Underfilled samples were classified three groups (group 1, N = 44; group 2, N = 36; and group 3, N = 29) according to the filling ratio of the samples; 0.5 mL and below (< 25%), 0.5-1.0 mL (25-50%), and 1.0-2.0 mL (> 50%), respectively. When we compared underfilled tubes with pairing filled tubes, there was a statistically significant difference only with tubes filled less than 25% (P = 0.030). Furthermore, we have done bias analysis between paired tubes according to the diagnostic cut-off value of 6.5%. The bias was more prominent in up to 50% underfilled blood tubes (1.1%), when HbA1c concentrations were below the diagnostic cut-off of 6.5%.

Conclusions

We suggest that the blood tubes with EDTA for HbA1c measurement should be filled with at least 50% to avoid clinical variations.

Narrative Review of glycaemic management in people with diabetes on peritoneal dialysis

There is an increasing number of people with diabetes on peritoneal dialysis (PD) worldwide. However, there is a lack of guidelines and clinical recommendations for managing glucose control in people with diabetes on PD. The aim of this review is to provide a summary of the relevant literature and highlight key clinical considerations with practical aspects in the management of diabetes in people undergoing PD. A formal systematic review was not conducted because of the lack of sufficient and suitable clinical studies. A literature search was performed using PubMed, MEDLINE, Central, Google Scholar and ClinicalTrials.gov., from 1980 through February 2022. The search was limited to publications in English. This narrative review and related guidance have been developed jointly by diabetologists and nephrologists, who reviewed all available current global evidence regarding the management of diabetes in people on PD.We focus on the importance of individualized care for people with diabetes on PD, the burden of hypoglycemia, glycemic variability in the context of PD and treatment choices for optimizing glucose control. In this review, we have summarized the clinical considerations to guide and inform clinicians providing care for people with diabetes on PD.

Evaluation of interference from 16 hemoglobin variants on hemoglobin A1c measurement by five methods

Hb variants prevalent in China are different from those in other countries. We aimed to assess the interference from Hb variants found in China on HbA1c measurement. All Hb variants were confirmed using Sanger sequencing. HbA1c was measured using a capillary electrophoresis method (Capillarys 3 OCTA), two cation-exchange high-performance liquid chromatography methods (ADAMS HA-8180V and HLC-723 G8 standard mode), an immunoassay (Cobas c501), and a boronate affinity chromatography method (Premier Hb9210). Premier Hb9210 was used as a comparative method. A total of 16 species of Hb variants were identified in 102 variant carriers. The most common variant was Hb E, followed by Hb Q-Thailand, Hb New York and Hb J-Bangkok. Clinically significant interference was observed for the Capillarys 3 OCTA (two Hb variants), ADAMS HA-8180V (seven Hb variants), HLC-723 G8 (14 Hb variants), and Cobas c501 (two Hb variants). The proportion of unacceptable HbA1c results was 13.7% for Capillarys 3 OCTA, 52.9% for HA-8180V, 83.3% for HLC-723 G8, and 3.9% for Cobas c501. Hb variants in China severely affect the accuracy of some commonly used HbA1c methods.

SNAP participation moderates the association between household food insecurity and HbA1c among Cambodian Americans with depression

OBJECTIVES

We tested whether participation in the Supplemental Nutrition Assistance Program (SNAP) moderated the relation between household food insecurity and HbA1c among Cambodian Americans with depression enrolled in a diabetes prevention trial.

METHODS

Community health workers assessed household food insecurity and SNAP participation. HbA1c was ascertained using direct enzymatic assay.

RESULTS

Among the n = 189 respondents, 19% were food insecure, 41% received SNAP benefits, and mean HbA1c = 5.5%. There was a significant interaction between SNAP and food insecurity. HbA1c was highest among participants without SNAP who were food insecure. Simple effects analysis revealed a significant difference within the no SNAP group [Mean (SD): Secure = 5.38 (0.38), Insecure = 5.78 (0.36)] and no difference within the SNAP group [Secure = 5.61(0.44), Insecure = 5.61(0.55)]. Differences remained significant after controlling for demographic, socioeconomic, and clinical indicators.

CONCLUSIONS

SNAP may protect against the deleterious association between household food insecurity and HbA1c.

Remote capillary blood collection for HbA1c measurement during the COVID-19 pandemic: A laboratory and patient perspective

AIMS

The purpose of this study was to assess the clinical performance and user acceptance of capillary blood samples prepared remotely using the MiniCollect® capillary blood collection device as an alternative to blood collection by venepuncture for glycated haemoglobin (HbA_1c ) analysis.

METHODS

Following written informed consent, a cross-sectional study was conducted in individuals aged ≥18 years with any type of diabetes who routinely self-monitor their blood glucose. Eligible participants recruited whilst attending their routine clinical appointments were required to provide a venous blood sample, prepare a capillary blood sample at home (remotely) and complete a bespoke questionnaire. HbA_1c in whole blood collected in ethylenediaminetetraacetic acid was determined by capillary electrophoresis on the Sebia Capillary's 3 Tera analyser following standard operating procedure.

RESULTS

HbA_1c results from both venous and capillary collection demonstrated good agreement. Passing-Bablok regression: y = 0 + 1x (p = 0.18), Spearman correlation r = 0.986, p < 0.0001. The Bland-Altman difference plot provided a mean difference of 0.3 mmol/mol (2.2%). Over half of the participants found the MiniCollect device easy to use. The majority of participants were in favour of the remote capillary blood collection service and would use it if routinely available.

CONCLUSION

The home collection of capillary blood for HbA_1c determination is a valuable and convenient alternative to standard venous blood collection as it provides an opportunity to support routine HbA_1c monitoring, whilst mitigating the transmission of SARS-CoV-2. This service would additionally allow individuals to attend clinic visits with a HbA_1c value, ensuring optimal continuance of patient care for individuals with diabetes.

Variation in the hemoglobin glycation index

A high hemoglobin glycation index (HGI) has been repeatedly associated with greater risk for hypoglycemia in people with diabetes and greater risk for chronic vascular disease in people with or without diabetes. This review explores how different sources of analytical and biological variation in HbA1c and blood glucose individually and collectively affect the clinical information value of HGI. We conclude that HGI is a complex quantitative trait that is a clinically practical biomarker of risk for both hypoglycemia and chronic vascular disease.

Potential misclassification of diabetes and prediabetes in the U.S.: Mismatched HbA1c and glucose in NHANES 2005-2016

AIMS

To assess the prevalence and clinical implications of "mismatches" between HbA1c and glucose levels in the United States across the life course.

METHODS

Participants ages 12-79 years from U.S. National Health and Nutrition Examination Survey (NHANES) 2005-2016 without known diagnosis of diabetes and who had a 75 g oral glucose tolerance test were included. Previously undiagnosed diabetes (DM), prediabetes, and normal glucose metabolism (NGM) were defined using American Diabetes Association cut-points. Mismatches were defined by the hemoglobin glycation index (HGI).

RESULTS

In 10,361 participants, 5% and 41% had diabetes and prediabetes, respectively, by fasting or 2-hour glucose criteria. By HbA1c criteria, the high HGI tertile consisted of mostly abnormal classification (3% DM, 52% prediabetes) and the low HGI tertile contained mostly normal classification (78% NGM). Across all ages, 15% (weighted: 30 million individuals) had clinically significant mismatches of HGI magnitude ≥+0.5% (i.e., high mismatch) or ≤-0.5% (low mismatch). Mismatch was most common in older adults and non-Hispanic Black participants.

CONCLUSIONS

Mismatches of clinically significant magnitude could lead to HbA1c-related misdiagnosis or inappropriate management in up to 30 million Americans. Older adults, non-Hispanic Black individuals, and others with high mismatches may benefit from complementing HbA1c with additional diagnostic and management strategies.

Identification of Hemoglobin Variants Prevalent in China and Their Effects on Hemoglobin A1c Measurements

OBJECTIVES

We aimed to evaluate the effects of hemoglobin (Hb) variants prevalent in China on HbA1c measurements and to identify them during HbA1c measurements.

METHODS

We evaluated a cation-exchange high-performance liquid chromatography (HPLC) method (Bio-Rad D-100), a capillary electrophoresis (CE) method (Capillarys 3 TERA), an immunoassay (Cobas c501), and a boronate affinity method (Premier Hb9210, as a comparative method) for HbA1c measurements in the presence of Hb variants prevalent in China.

RESULTS

The Bio-Rad D-100 and Capillarys 3 TERA gave specific retention times and numeric migration positions for each Hb variant, respectively, showing excellent interindividual reproducibility. All methods showed statistically significant differences (P < .01) for several variants. Clinically significant effects were observed for the Bio-Rad D-100 (Hb New York and Hb J-Bangkok), Capillarys 3 TERA (Hb New York and Hb J-Bangkok), and Cobas c501 (Hb New York). Among 297 samples with Hb variants, there were 75 (25.3%) unacceptable results for Bio-Rad D-100, 28 (9.4%) for Capillarys 3 TERA, and 19 (6.4%) for Cobas c501 compared with the results from Premier Hb9210.

CONCLUSIONS

Some Hb variants prevalent in China affect HbA1c measurements. The HPLC retention time and CE migration position can aid in the presumptive identification of Hb variants.

Feasibility and Performance of Hemoglobin A1C Self-Testing During COVID-19 Among African Americans With Type 2 Diabetes

PURPOSE

The purpose of the study was to determine the feasibility of implementing A1C self-testing at home using the A1CNow® Self Check and to compare the accuracy of the A1CNow to a reference standard in African Americans with type 2 diabetes (T2D).

METHODS

African American adults with T2D were recruited from 13 different churches (N = 123). Phase 1, conducted during the early phase of the COVID-19 pandemic, examined the feasibility of A1C assessment using the A1CNow performed at home by untrained participants. Phase 2, conducted when in-person research resumed, compared A1C values concurrently measured using the A1CNow and the DCA Vantage™ Analyzer (reference standard) collected by research staff at church testing sites.

RESULTS

In Phase 1, 98.8% of participants successfully completed at least 1 at-home A1C test; the overall failure rate was 24.7%. In Phase 2, the failure rate of staff-performed A1CNow testing was 4.4%. The Bland-Altman plot reveals that A1CNow values were 0.68% lower than DCA values, and the mean differences (A1CNow minus DCA) ranged from -2.6% to 1.2% with a limit of agreement between -1.9% to 0.5%.

CONCLUSIONS

A1C self-testing is feasible for use in community settings involving African American adults with T2D. The A1CNow Self-Check underestimated A1C values when compared with the reference standard. Ongoing improvements in point-of-care devices have the potential to expand research and clinical care, especially in underserved communities.

Combining HbA1c and glycated albumin improves detection of dysglycaemia in mixed-ancestry South Africans

BACKGROUND

Combining HbA_1c with glycated albumin (GA) may improve detection of dysglycaemia. As BMI correlates positively with HbA_1c and negatively with GA, HbA_1c may be more effective in obese and GA in nonobese individuals.

METHODS

To relate these findings to Africans, we assessed in 1274 South Africans living in CapeTown (male 26%; age 48±16y; BMI 28.7 kg/m² (range 15.6-73.8); obesity 39.9% and no prior diabetes history) the: (1) correlation of BMI with HbA_1c and GA, (2) ability of HbA_1c and GA separately and jointly, to detect OGTT-diagnosed dysglycaemia (diabetes plus prediabetes). Data collection took place between 2014 and 2016 in the City of Cape Town. Dysglycaemia was diagnosed by glucose criteria for the OGTT. Youden index was used to optimize diagnostic thresholds for HbA_1c and GA.

FINDINGS

Normal glucose tolerance, prediabetes and diabetes occurred in 76%, 17% and 7%, respectively. BMI positively correlated with HbA_1c [r = 0·34 [95%CI: 0·29,0·39)] and negatively with GA [-0·08 (0·13,0·03)]. For HbA_1c the optimal threshold by Youden-index for dysglycaemia diagnosis was: 6·0% (95%CI: 5·8,6·2) and for GA: 13·44% (12·72,14·71). In the nonobese, obese and total cohort, HbA_1c-alone detected: 51% (42-60), 72% (65,78), 63% (57,68), respectively; GA-alone detected 55% (52% (46,63), 52% (44, 59) and 53% (47,53), respectively; whereas: HbA_1c+GA detected: 69% (60,76), 82% (75,87) and 76% (71, 81). Therefore, for the total cohort detection of dysglycaemia HbA_1c-alone vs HbA_1c+GA detected 63% (57,68) vs 76% (71,81).

INTERPRETATION

The opposite correlations of HbA_1c and GA with BMI have now been demonstrated in an African-based population. Improving detection of dysglycaemia by combining HbA_1c and GA has important implications for diabetes risk screening.

FUNDING

AES is supported by the intramural programs of the National Institute of Diabetes and Digestive and Kidney Diseases and the National Institute of Minority Health and Health Disparities of the National Institutes of Health (NIH, Bethesda, Maryland, USA). DBS is supported by the intramural program of the Clinical Center of NIH. The South African Medical Research Council (SAMRC) funded the VMH study with funds from the National Treasury under its Economic Competitiveness and Support Package (MRC-RFA-UFSP-01-2013/VMH Study).

Glycated Hemoglobin Measurement: Comparison of Three Methods Versus High Performance Liquid Chromatography

BACKGROUND

HbA1c result provide information on metabolic control in diabetes mellitus (DM) and could also be used for its diagnosis. For its determination, the laboratory must be certified by the National Glycohemoglobin Standardization Program (NGSP) or the International Federation of Clinical Chemistry (IFCC) and comply with a strict quality control program.

AIMS

To determine the correlation and agreement between HbA1c results measured by three analytical methods (enzymatic, turbidimetric, and capillary electrophoresis) versus HPLC.

METHODS

Method comparison-1245 samples from equal number of subjects at 45 Association of High Complexity Laboratories (Asociación de Laboratorios de Alta Complejidad-ALAC) centers, centralizing sample processing and operator. Statistical analysis-analysis of variance (ANOVA) and nonparametric Friedman ANOVA test for related samples, means, and medians. Correlation and concordance-Pearson's correlation and linear regression, intraclass correlation coefficient (Passing and Bablock and Bland and Altman).

RESULTS

The comparison of mean values obtained by the four methods showed statistically significant, but clinically irrelevant, differences: HbA1c by HPLC versus Electrophoresis 0.06% (0.42 mmol/mol) P = .000 (± 1.96 DS -0.070 -0.047), Enzymatic 0.087% (1 mmol/mol) P = .000 (± 1.96 DS 0.077 0.098), Turbidimetric 0.056% (0.38 mmol/mol) P = 0.000 (± 1.96 DS -0.067 -0.044). Their concordance showed intraclass correlation of single measures of 0.982 P < .001 (95% CI 0.987 - 0.9838).

CONCLUSIONS

The three methods present low variability and high correlation versus the HPLC.

KDOQI US Commentary on the KDIGO 2020 Clinical Practice Guideline for Diabetes Management in CKD

In October 2020, KDIGO (Kidney Disease: Improving Global Outcomes) published its first clinical practice guideline directed specifically to the care of patients with diabetes and chronic kidney disease (CKD). This commentary presents the views of the KDOQI (Kidney Disease Outcomes Quality Initiative) work group for diabetes in CKD, convened by the National Kidney Foundation to provide an independent expert perspective on the new guideline. The KDOQI work group believes that the KDIGO guideline takes a major step forward in clarifying glycemic targets and use of specific antihyperglycemic agents in diabetes and CKD. The purpose of this commentary is to carry forward the conversation regarding optimization of care for patients with diabetes and CKD. Recent developments for prevention of CKD progression and cardiovascular events in people with diabetes and CKD, particularly related to sodium/glucose cotransporter 2 (SGLT2) inhibitors, have filled a longstanding gap in nephrology's approach to the care of persons with diabetes and CKD. The multifaceted benefits of SGLT2 inhibitors have facilitated interactions between nephrology, cardiology, endocrinology, and primary care, underscoring the need for innovative approaches to multidisciplinary care in these patients. We now have more interventions to slow kidney disease progression and prevent or delay kidney failure in patients with diabetes and kidney disease, but methods to streamline their implementation and overcome barriers in access to care, particularly cost, are essential to ensuring all patients may benefit.

Periodic Comparability Verification and Within-Laboratory Harmonization of Clinical Chemistry Laboratory Results at a Large Healthcare Center With Multiple Instruments

Background

Results from laboratories using multiple instruments should be standardized or harmonized and comparability-verified for consistent quality control. We developed a simple frequent comparability verification methodology applicable to large healthcare centers using multiple clinical chemistry instruments from different manufacturers.

Methods

Comparability of five clinical chemistry instruments (Beckman Coulter AU5800, Abbott Architect Ci16000, two Siemens Vista 1500, and Ortho Vitros 5600) was evaluated from 2015 to 2019 for 12 clinical chemistry measurements. Pooled residual patient samples were used for weekly verifications. Results from any instrument exceeding the allowable verification range versus the results from the comparative instrument (AU5800) were reported to clinicians after being multiplied by conversion factors that were determined via a linear regression equation obtained from simplified comparison.

Results

Over the five-year study period, 432 weekly inter-instrument comparability verification results were obtained. Approximately 58% of results were converted due to non-comparable verification. Expected average absolute percent bias and percentage of non-comparable results for non-converted and converted results after conversion action were much lower than those for data measured before conversion action. The inter-instrument CV for both non-converted and converted results after conversion action was much lower than that for measured data before conversion action for all analytes.

Conclusions

We maintained within-laboratory comparability of clinical chemistry tests from multiple instruments for five years using frequent low-labor periodic comparability verification methods from pooled residual sera. This methodology is applicable to large testing facilities using multiple instruments.

Sex-Specific Associations of Iron-Anemia Status With Hemoglobin A1C Levels Among Hispanics/Latinos Without Self-Reported Diabetes Mellitus: The Hispanic Community Health Study/Study of Latinos

OBJECTIVE

The objective of this study was to examine the sex-specific associations of mutually exclusive iron-anemia status categories with hemoglobin A1C (HbA1C) levels among U.S. Hispanics/Latinos without self-reported diabetes mellitus.

METHODS

Baseline cross-sectional data (7247 women and 4904 men without self-reported diabetes mellitus) from the Hispanic Community Health Study/Study of Latinos were analyzed. Per the American Diabetes Association's defined criteria, based on HbA1C levels, the participants were categorized as having normoglycemia, prediabetes, or probable diabetes mellitus. The iron-anemia status categories were as follows: no anemia and no iron deficiency (reference), iron deficiency, iron deficiency anemia (IDA), and non-iron deficiency anemia (non-IDA). Survey multinomial logistic regression models were used to examine the sex-specific associations of iron-anemia status with HbA1C levels after adjusting for sociodemographic, lifestyle, and clinical factors.

RESULTS

The age-standardized prevalence of iron-anemia status categories differed by sex. Compared with those with no anemia and no iron deficiency and normoglycemia, women with IDA had higher odds of having prediabetes (odds ratio [OR], 2.18; 95% CI, 1.64-2.89) and probable diabetes mellitus (OR, 3.59; 95% CI, 1.62-7.99) based on HbA1C levels; men with non-IDA had higher odds of having probable diabetes mellitus (OR, 2.97; 95% CI, 1.13-7.78) based on HbA1C levels. All other associations did not reach statistical significance.

CONCLUSION

Among U.S. Hispanics/Latinos without self-reported diabetes mellitus, the age-standardized prevalence of iron deficiency, IDA, and non-IDA is high and varies by sex. Women with IDA had higher odds of having prediabetes and probable diabetes mellitus, defined based on HbA1C levels. Men with non-IDA had higher odds of having probable diabetes mellitus, defined based on HbA1C levels. Iron-anemia status should be considered while interpreting elevated HbA1C levels among U.S. Hispanics/Latinos without self-reported diabetes mellitus.

Differences in complications, cardiovascular risk factor, and diabetes management among participants enrolled at veterans affairs (VA) and non-VA medical centers in the glycemia reduction approaches in diabetes: A comparative effectiveness study (GRADE)

AIMS

We evaluated differences in participants with type 2 diabetes (T2DM) enrolled in the GRADE study at VA vs non-VA sites, focusing on cardiovascular risk factors and rates of diabetes care target achievements.

METHODS

We compared baseline characteristics between participants at VA (n = 1216) and non-VA (n = 3831) sites, stratifying analyses by cardiovascular disease (CVD) history.

RESULTS

VA and non-VA participants had similar diabetes duration (4.0 years), HbA1c (7.5%), and BMI (34 kg/m²); however, VA participants had more individuals ≥ 65 years (37.3% vs 19.8%, p < 0.001), men (90.0% vs 55.2%, p < 0.001), hypertension (75.8% vs 63.6%, p < 0.001), hyperlipidemia (76.6% vs 64.6%, p < 0.001), current smokers (19.0% vs 12.1%, p < 0.001), nephropathy (20.4% vs 17.0%, p < 0.05), albuminuria (18.4% vs 15.1%, p < 0.05), and CVD (10.4% vs 5.2%, p < 0.001). In those without CVD, more VA participants were treated with lipid (70.8% vs 59.5%, p < 0.001) and blood pressure (74.9% vs 65.4%, p < 0.001) lowering medications, and had LDL-C < 70 mg/dl (32.9% vs 24.2%, p < 0.05). Among those with CVD, more VA participants had BP < 140/90 (80.2% vs 70.1%, p < 0.05) after adjusting for demographics.

CONCLUSION

GRADE participants at VA sites had more T2DM complications, greater CVD risk and were more likely to be treated with medications to reduce it, leading to more LDL-C at goal than non-VA participants, highlighting differences in diabetes populations and care.