Factors affecting A1C in non-diabetic individuals: Review and meta-analysis

2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Prevalence of prediabetes in patients with idiopathic frozen shoulder: a prospective study

Background

The association between diabetes and frozen shoulder is well established. However, the data regarding prediabetes and primary frozen shoulder (PFS) are still lacking.

Methods

In a prospective study, 158 patients with PFS were included. The prediabetes status was ascertained by estimating serum hemoglobin A1c (HbA1c) levels in patients with PFS. According to the level of HbA1c, patients were classified into normoglycemic, prediabetic, and diabetic. In addition, random blood sugar (RBS) was also performed.

Results

Out of 158 participants, 84 (53.2%) were male and 74 (46.8%) were female. Nine patients had bilateral shoulder involvement, and all were diabetics; 47.5% (n = 75) of the patients were in the age group of 51-60 years, 16.5% (n = 26) of the participants were normoglycemic, 37.3% (n = 59) were prediabetics, and 46.2% (n = 73) were diabetics. The difference in mean HbA1c values between the 3 groups was statistically significant (P < .001). However, there was no statistical difference in various age groups (P = .86) or gender (P = .68) between normoglycemics, prediabetics, and diabetics. The difference in mean RBS values between diabetic-nondiabetic and diabetic-prediabetic groups were statistically significant (P < .001), whereas no significant difference was detected between nondiabetic and prediabetic (P = .355).

Conclusion

The prevalence of prediabetes is 37.5% in patients with PFS. Single-point HbA1c estimation is an acceptable tool to detect prediabetes, whereas RBS estimation should not be used to detect prediabetes.

Fetal pancreas size and maternal serum biomarkers glycated albumin and insulin-regulated aminopeptidase provide no potential for early prediction of gestational diabetes mellitus

PURPOSE

We aimed to determine the predictive values of fetal pancreas size and maternal serum biomarkers glycated albumin (GA) and insulin-regulated aminopeptidase (IRAP) for gestational diabetes mellitus (GDM).

MATERIALS AND METHODS

In this prospective observational study including 109 pregnant women, the fetal pancreas size and maternal serum biomarkers GA and IRAP were measured at the gestational age of 20-22 weeks and later at the gestational age of 24-28 weeks, in 19 participants of them, GDM was confirmed with the 75-g oral glucose tolerance test (OGTT) and the fetal pancreas size was measured in all the participants again.

RESULTS

The median fetal pancreas sizes were significantly higher in women with or without GDM when measured at the 24-28 weeks of pregnancy compared to those at the 20-22 weeks of pregnancy (p < 0.05). At both of the 20-22 and 24-28 weeks of pregnancy, the median values of fetal pancreas sizes in the women with or without GDM were found comparable (p > 0.05). There were no significant differences between pregnant women with or without GDM regarding maternal serum biomarkers GA and IRAP (p > 0.05). Multivariate logistic regression analysis revealed no meaningful association of study parameters with the development of GDM.

CONCLUSION

The fetal pancreas size and maternal serum biomarkers GA and IRAP provide no potential for early prediction of GDM at the 20-22 weeks of gestation. Further studies, including serial measurement of these parameters during the second and third trimesters of GDM pregnancies, may clarify their role in the antenatal care of women with GDM.

CLINICAL TRIALS

NCT05392231.

2. Classification and Diagnosis of Diabetes: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Dietary patterns, oxidative Stress, inflammation and biological variation in hemoglobin A1c: Association and Mediation analysis in a rural community in north China

OBJECTIVE

The aim is to assess the relationship between the hemoglobin glycation index(HGI) and dietary patterns, and investigates whether inflammation and oxidative stress mediate the relationship.

METHODS

Cross-sectional data were collected from 453 dwellers in a Chinese rural community. Diet was assessed using 24 h food recalls. Based on the energy intake ratio from three macronutrients, dietary patterns were identified by cluster analysis. The HGI was defined as the observed HbA1c minus predicted HbA1c. Indicators of inflammation and oxidative stress were assessed.

RESULT

3 dietary patterns were clustered, namely "fat(n = 100)", "balance(n = 186)" and "carbohydrate(n = 167)". The fat dietary patterns had lower HGI than the other two dietary patterns. TNFα was higher in the carbohydrate dietary pattern. Linear regression analysis suggested that the carbohydrate dietary pattern was correlated with higher HGI levels(β = 0.204,95 %CI(0.071,0.338)), compared with the fat dietary pattern. The relationship disappeared after accounting for biomarkers of inflammation and oxidative stress. Mediation analyses indicated that TNFα might explain for 19.15 % effects of the carbohydrate dietary pattern on HGI, compared with the fat dietary pattern.

CONCLUSION

The carbohydrate dietary pattern had positive associations with HGI and TNFα. TNFα partly mediated the relationship between dietary patterns and HGI.

Relationship between glycosylated hemoglobin and iron deficiency anemia: A common but overlooked problem

INTRODUCTION

Both diabetes mellitus (DM) and iron deficiency anemia (IDA) are prevalent in every area of the world, and so, the possibility of these two diseases co-existing is also very high. It is our belief that clinical results of any correlation between iron status of the body and glycosylated haemoglobin (HbA1c) would be beneficial to many patients, therefore in this study, the effect of IDA on HbA1c was investigated.

MATERIALS - METHODS

A total of 146 patients with DM and IDA were evaluated prospectively. While the patients were administered 270 mg/day of ferrous sulphate (80 mg elemental iron) orally for three months for the treatment of IDA, no interventions were made for the treatment of DM. Patient levels of hemoglobin (Hb), hematocrit, red blood cells (RBC), mean corpuscular volume (MCV), platelet, white blood cells (WBC), serum iron, serum iron binding capacity (SIBC), ferritin, fasting plasma glucose (FPG), HbA1c, body mass index (BMI), C-reactive protein (CRP) values were measured at baseline and at the third month of treatment with iron, and were compared.

RESULTS

The median age of our patients was 45 (40-50) and median duration of diabetes was 3 years (1,75-5). While the baseline median Hb was 10.4 (mg/dL) (9.5-11.1), MCV was 74 (fL) (70.8-77), ferritin was 4 (ug/L) (3-6) at three months, Hb was measured at 12.6 (mg/dL) (12.1-13.2), MCV was measured at 82 (fL) (80-86), ferritin was measured at 15 (ug/L) (9-21.2) and was significantly higher compared to baseline values (p < 0.001). The baseline median HBA1c of patients was 7.09 ± 0.51 (%) and three month HBA1c was 6.69 ± 0.53 (%), which was significantly lower than when comparing baseline values with values at third month (p < 0.001). Baseline and three month values for FPG were 118 (mg/dL) (108-132) and 116 (mg/dL) (106-125) respectively, and there was no significant difference (p:0.07). A 2.2 mg/dL (1.5-3.5) increase in median Hb level accompanied a 0.4 % (0.2-0.6) decrease in median HbA1c levels (Spearman rho = -0.362; p < 0.001).

CONCLUSION

Our study has shown conclusivly that IDA is related to increased HbA1c concentrations and HbA1c decreases significantly following treatment with iron. IDA should be considered before making any decisions regarding diagnosis or treatment according to HbA1c.

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.

2. Classification and Diagnosis of Diabetes: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

The effect of almond intake on glycemic control: A systematic review and dose-response meta-analysis of randomized controlled trials

Number trials have evaluated the effect of almond intake on glycemic control in adults; however, the results remain equivocal. Therefore, the present meta-analysis aims to examine the effectiveness of almond intake on glycemic parameters. Online databases including PubMed, Scopus, ISI web of science, Embase, and Cochrane Library were searched up to August 2021 for trials that examined the effect of almond intake on glycemic control parameters including fasting blood sugar (FBS), insulin, HOMA-IR, and HbA1C. Treatment effects were expressed as mean difference (MD) and the standard deviation (SD) of outcomes. To estimate the overall effect of almond intake, we used the random-effects model. In total, 24 studies with 31 arms were included in our analysis. The meta-analysis revealed that almond intake did not significantly change the concentrations of FBS, HbA1c, insulin levels, and HOMA-IR. In conclusion, there is currently no convincing evidence that almonds have a clear beneficial effect on glycemic control. Future studies are needed before any confirmed conclusion could be drowned.

The impact of ferritin on the disassociation of HbA1c and mean plasma glucose

OBJECTIVE

To explore the impact of ferritin level on the disassociation of glycated hemoglobin A1c (HbA1c) and mean plasma glucose (MPG).

RESEACH DESIGN AND METHODS

We used a 2012-2013 cross-sectional survey conducted in Pinggu district, Beijing including 3095 Chinese participants aged 25-75 years. We categorized their glycemic status by interviewing for diagnosed diabetes and by measuring HbA1c, fasting plasma glucose (FPG), and 2-hours post-load plasma glucose (2-hours PPG). We fitted a multivariable regression model to explore the impact of ferritin on the association of HbA1c or glycated albumin (GA) and mean plasma glucose.

RESULTS

A total of 5.65% of participants were diagnosed as diabetes using HbA1c criteria, and 9.79% using oral glucose tolerance test criteria. Compared with males, females had significantly lower hemoglobin levels (159.82 ± 11.56 vs 135.93 ± 12.62) and lower ferritin levels (113.00 [68.55, 185.50] vs 33.40 [12.40, 70.13]). Linear regression analysis performed in different groups classified by different diagnose criterion indicated that the correlation between MPG and HbA1c differs in different tertiles of ferritin (lowest vs middle vs highest: R² = 0.507 vs 0.645 vs 0.687 in female; R² = 0.415 vs 0.715 vs 0.615 in male), and the association between MPG and HbA1c diminished in the lowest tertile of ferritin.

CONCLUSIONS

Ferritin level might affect the association between glucose and HbA1c, which should be taken into account when using HbA1c as a diagnosis criterion for diabetes and prediabetes.

Association Between Hemoglobin Glycation Index and Risk of Cardiovascular Disease and All Cause Mortality in Type 2 Diabetic Patients: A Meta-Analysis

Background: The hemoglobin glycation index (HGI) has been proposed as a marker to quantify inter-individual variation in hemoglobin glycosylation. However, whether HGI is associated with an increased risk of diabetic complications independent of glycated hemoglobin (HbA1c) remains unclear. This meta-analysis aimed to determine the association between HGI and the risk of all cause mortality and composite cardiovascular disease (CVD).

Methods: PubMed, and EMBASE databases were searched for related studies up to March 31, 2021. Observational studies reported associations between HGI levels and composite CVD and all cause mortality were included for meta-analysis. A random effect model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CI) for higher HGI.

Results: A total of five studies, comprising 22,035 patients with type two diabetes mellitus were included for analysis. The median follow-up duration was 5.0 years. After adjusted for multiple conventional cardiovascular risk factors, an increased level of HGI was associated with a higher risk of composite CVD (per 1 SD increment: HR = 1.14, 95% CI = 1.04–1.26) and all cause mortality (per 1 SD increment: HR = 1.18, 95% CI = 1.05–1.32). However, when further adjusted for HbA1c, the association between HGI and risk of composite CVD (per 1 SD increment of HGI: HR = 1.01, 95% CI = 0.93–1.10) and all cause mortality (per 1 SD increment of HGI: HR = 1.03, 95% CI = 0.96–1.10) became insignificant.

Conclusions: High HGI was associated with an increased risk of composite CVD and all cause mortality after adjustment for multiple conventional cardiovascular risk factors. However, the association was mainly mediating by the level of HbA1c.

Factors associated with glycated albumin in adults without diabetes

Background and aims

Glycated albumin is a glycemic marker useful in short-term monitoring and in situations when a glycated hemoglobin test is not reliable. This study aims to evaluate glycated albumin levels and its associated factors in normoglycemic adults from Southern Brazil.

Method

136 individuals, without diabetes or pre-diabetes, were included in this cross-sectional study. Levels of glycated albumin, glycated hemoglobin, and other biochemical markers were measured.

Results

Glycated albumin levels ranged from 11.1% to 17.5% (2.5^th and 97.5^th percentiles). Glycated albumin/glycated hemoglobin ratio was 2.8±0.2. Glycated albumin did not differ according to gender and age groups. However, in overweight individuals, levels of glycated albumin and glycated albumin/glycated hemoglobin ratio were lower and weakly and negatively correlated with body mass index.

Conclusions

Glycated albumin levels in Brazilians were similar to those previously described in other populations. Glycated albumin seems to be irrespective of gender or age, but weakly correlated with weight. These aspects should be taken into account in the interpretation of glycated albumin results.

One-hour plasma glucose concentration can identify elderly Chinese male subjects at high risk for future type 2 diabetes mellitus: A 20-year retrospective and prospective study

AIM

There have been few reports regarding the association between 1 h-PG concentration and type 2 diabetes mellitus (T2DM) in the elderly. This study was performed to assess the efficacy of 1 h-PG and 2 h-PG values in predicting future risk of T2DM in elderly.

METHODS

The study population consisted of 928 male volunteers ≥ 55 years old without diabetes who were involved in a retrospective-prospective cohort study over 20 years with a baseline fasting plasma glucose (FPG) and OGTT that included measurement of 1 h-PG and 2 h-PG. The predictive capabilities of FPG and 1 h-PG, 2 h-PG values obtained during OGTT alone and added to a clinical prediction model consisting of traditional diabetes risk factors were assessed.

RESULTS

Overall, 577 of all the 928 study participants (62%) developed T2DM over the 20-year follow-up. 1 h-PG and 2 h-PG values predicted T2DM and remained independent predictors of T2DM after adjusting for various traditional risk factors [HR = 1.269 (95% CI = 1.214-1.327), P < 0.001; HR = 1.269 (95% CI = 1.179-1.366), P < 0.001, respectively]. C-statistics for 1-h PG (C-statistics 0.794 [95% CI 0.765-0.823]) was significantly greater than that for 2-h PG (C-statistic 0.747 [95% CI 0.716-0.779]) in models adjusting for various traditional risk factors. 1 h-PG had the greatest area under the ROC curve (AUC, 0.766), which was greater than that of 2 h-PG (0.719).

CONCLUSIONS

1 h-PG is useful as a predictor of future development of T2DM independently of traditional risk factors in an elderly Chinese male population.

Evaluation of Chitotriosidase and Neopterin as Biomarkers of Microvascular Complications in Patients with Type 1 Diabetes Mellitus

The chronic complications of diabetes mellitus (DM) are accompanied by inflammatory manifestations. Our study aimed to evaluate a possible association between the inflammatory status (reflected by serum chitotriosidase and neopterin) and the timely evolution and occurrence of chronic microvascular complications in patients with type 1 DM. This observational, cross-sectional study included 82 type 1 DM patients from the Centre for Diabetes, Nutrition and Metabolic Diseases, Cluj-Napoca, Romania. Our results demonstrated a link between the extent of inflammation, evaluated by the enzymatic activity of circulating chitotriosidase, and the onset of microvascular complications, especially diabetic neuropathy and retinopathy. Chitotriosidase enzymatic activity showed an ascending evolution over time. In non-smoking patients, the increase in chitotriosidase activity was correlated with the extent of microalbuminuria and the decline of glomerular filtration rate, while in smokers, only the presence of a positive correlation between chitotriosidase activity and disease progression was noticed. According to our results, the time span between the moment of diagnosis and the onset of microvascular complications was longer in non-smokers than in smokers. These results also imply that increased chitotriosidase activity may be a predictor of endothelial dysfunction in type 1 DM.

Hemoglobin glycation index is associated with incident chronic kidney disease in subjects with impaired glucose metabolism: A 10-year longitudinal cohort study

AIM

We investigated the associations between hemoglobin glycation index (HGI) and incident chronic kidney disease (CKD) in treatment-naïve subjects with prediabetes or diabetes.

METHODS

We conducted a prospective cohort study comprising 2187 subjects with prediabetes or diabetes. HGI was calculated as the difference between the measured and predicted values of HbA1c using the linear relationship between HbA1c level and fasting plasma glucose levels. Incident CKD was considered if eGFR decreased to <60 mL/min/1.73 m² and by >25% from the baseline value during follow up. The hazard ratios (HRs) for incident CKD were calculated using Cox proportional hazards regression models.

RESULTS

The overall prevalence of CKD was 15.3% (n = 335) during the 10-year follow-up period. The prevalence of CKD increased significantly from the low to the high HGI groups. In the multivariate analysis, the highest HGI group showed the highest adjusted HR for incident CKD (HR, 1.57; 95% confidence interval, 1.06-2.34), and this remained significant even after adjusting for the HbA1c level.

CONCLUSIONS

High HGI was associated with an increased risk of incident CKD among treatment-naïve subjects with prediabetes or diabetes, suggesting that HGI may be used to predict CKD in these patients regardless of HbA1c levels.

Diabetes mellitus in chronic kidney disease: Biomarkers beyond HbA1c to estimate glycemic control and diabetes-dependent morbidity and mortality

Diabetes mellitus (DM) is the leading cause of chronic kidney disease (CKD). Optimal glycemic control contributes to improved outcomes in patients with DM, particularly for microvascular damage, but blood glucose levels are too variable to provide an accurate assessment and instead markers averaging long-term glycemic load are used. The most established glycemic biomarker of long-term glycemic control is HbA1c. Nevertheless, HbA1c has pitfalls that limit its accuracy to estimate glycemic control, including the presence of altered red blood cell survival, hemoglobin glycation and suboptimal performance of HbA1c assays. Alternative methods to evaluate glycemic control in patients with DM include glycated albumin, fructosamine, 1-5 anhydroglucitol, continuous glucose measurement, self-monitoring of blood glucose and random blood glucose concentration measurements. Accordingly, our aim was to review the advantages and pitfalls of these methods in the context of CKD.

Diagnostic accuracy of glycated hemoglobin for gestational diabetes mellitus: a systematic review and meta-analysis

Background We conducted a systematic review and meta-analysis to establish the overall accuracy of glycated hemoglobin (HbA1c) in the diagnosis of gestational diabetes mellitus (GDM) diagnosis. Methods We searched MEDLINE, EMBASE, SCOPUS and ClinicalTrials.gov up to October 2018, using keywords related to GDM, HbA1c and diagnosis. Studies were included that were carried out with pregnant women without previous diabetes that assessed the performance of HbA1c (index test) compared to the 75 g oral glucose tolerance test (OGTT) (reference test) for the diagnosis of GDM, that measured HbA1c by standardized methods and presented data necessary for drawing 2 × 2 tables. Results This meta-analysis included eight studies, totaling 6406 pregnant women, of those 1044 had GDM. The diagnostic accuracy of HbA1c was reported at different thresholds ranging from 5.4% (36 mmol/mol) to 6.0% (42 mmol/mol), and the area under the curve (AUC) was 0.825 (95% confidence interval [CI] 0.751-0.899), indicating a good level of overall accuracy. The pooled sensitivities and specificities were 50.3% (95% CI 24.8%-75.7%) and 83.7% (67.5%-92.7%); 24.7% (10.3%-48.5%) and 95.5% (85.7%-98.7%); 10.8% (5.7%-19.41%) and 98.7% (96.2%-99.5%); 12.9% (5.5%-27.5%) and 98.7% (97.6%-99.3%), for the cut-offs of 5.4% (36 mmol/mol), 5.7% (39 mmol/mol), 5.8% (40 mmol/mol) and 6.0% (42 mmol/mol), respectively. Conclusions We observed a high heterogeneity among the studies. The effect of ethnicities, different criteria for OGTT interpretation and the individual performance of HbA1c methods may have contributed to this heterogeneity. The HbA1c test presents high specificity but low sensitivity regardless of the threshold used to diagnose GDM. These findings point to the usefulness of HbA1c as a rule-in test. HbA1c should be used in association with other standard diagnostic tests for GDM diagnosis.

A high triglyceride glucose index is more closely associated with hypertension than lipid or glycemic parameters in elderly individuals: a cross-sectional survey from the Reaction Study

Background

Both lipid and glucose abnormalities are associated with hypertension (HTN). However, it is unclear whether the triglyceride-glucose (TyG) index is associated with HTN. Therefore the aim of this study is to investigate the association of the TyG index and HTN and to compare the discriminative power of the TyG index, lipid, glycemic parameters for the risk of HTN in elderly individuals.

Methods

The present study was nested in a longitudinal (REACTION) study from May 2011 to December 2011, which was designed to demonstrate the association of abnormal glucose metabolism with the risk of cancer in the Chinese population. In total, 47,808 participants were recruited in this cross-sectional study. The TyG index was divided into five groups: the < 20% group, the 20–39% group, the 40–59% group, the 60–79% group and the ≥ 80% group, according to quintile division of the subjects. Three multivariate logistic regression models were used to evaluate the association between the TyG vs. lipid parameters, glycemic parameters and HTN.

Results

Multivariate logistic regression analysis shows that compared with lipid and glycemic parameters, the TyG index remains significantly associated with HTN in either total subjects or subjects separated into men and women (odds ratio (OR) 1.33, 95% confidence interval (CI) 1.18–1.51, p < 0.0001 in total subjects; OR 1.39, 95% CI 1.11–1.74, p = 0.0042 in men; OR 1.28, 95% CI 1.11–1.49, p = 0.0010 in women). In a stratified analysis, an elevated TyG index is significantly associated with HTN in the subgroup of the oldest age (≥ 65) (OR 1.67, 95% CI 1.30–2.14, p < 0.0001), as well as with obesity (Body mass index (BMI) ≥ 28 kg/m²) (OR 1.85, 95% CI 1.29–2.66, p = 0.0009) or lower estimated glomerular filtration rate (eGFR) (< 90 mL/(min·1.73 m²)) (OR 1.72, 95% CI 1.33–2.21, p < 0.0001).

Conclusion

The TyG index is significantly associated with HTN and shows the superior discriminative ability for HTN compared with lipid and glycemic parameters in the Chinese elderly population.

Glycated albumin as a diagnostic tool in diabetes: An alternative or an additional test?

Introduction

Studies have revealed that glycated albumin (GA) is a useful alternative to HbA_1c under conditions wherein the latter does not reflect glycaemic status accurately. Until now, there are few studies with non-Asians subjects that report on the validity of GA test in diagnosis of type 2 diabetes mellitus (DM). Thus, the aim of this study was to assess the clinical utility of GA in diagnosis of DM.

Materials and methods

This diagnostic test accuracy study was performed in 242 Brazilian individuals referred for OGTT in a tertiary university hospital. ROC curves were used to access the performance of GA and HbA_1c in the diagnosis of DM by oral glucose tolerance test (OGTT).

Results

OGTT, HbA_1c and GA were performed in all 242 participants (40.5% male, age 54.4 ± 13.0 years [mean ± SD], body mass index 28.9 ± 6.3 kg/m²). DM by OGTT was detected in 31.8% of individuals. The equilibrium threshold value of GA ≥14.8% showed sensitivity of 64.9% and specificity of 65.5% for the diagnosis of DM. The AUC for GA [0.703 (95% CI 0.631–0.775)] was lower than for HbA_1c [0.802 (95% CI 0.740–0.864)], p = 0.028. A GA value of 16.8% had similar accuracy for detecting DM as defined by HbA_1c ≥6.5% (48 mmol/mol) with sensitivity of 31.2% and specificity of 93.3% for both tests. However, GA detects different subjects from those detected by HbA_1c and OGTT.

Conclusions

GA detected different individuals with DM from those detected by HbA_1c, though it showed overall diagnostic accuracy similar to HbA_1c in the diagnosis of DM. Therefore, GA should be used as an additional test rather than an alternative to HbA_1c or OGTT and its use as the sole DM diagnostic test should be interpreted with caution.

Increased Levels of Glycated Hemoglobin A1c and Iron Deficiency Anemia: A Review

Worldwide, the prevalence of diabetes remains high. Studies have shown that iron deficiency anemia (IDA) is associated with increased levels of glycated hemoglobin A1c (HbA1c), but the mechanism remains unclear. Hematological changes, iron metabolism, study methodology, and other factors could affect the results of diagnostic investigations, leading to false results. Red blood cell turnover in the bone marrow and the quality and heterogeneity of erythrocytes may influence the rate of hemoglobin glycation. By changing the structure of hemoglobin and inducing peroxidation, iron deficiency accelerates glycation. This review aims to discuss the possible causes of the association between increased levels of HbA1c and IDA.

The haemoglobin glycation index is associated with nonalcoholic fatty liver disease in healthy subjects

OBJECTIVES

The hemoglobin glycation index (HGI) quantifies interindividual variations in glycated hemoglobin (HbA1c) and is associated with diabetic complications and metabolic diseases. However, information on the association between HGI and non-alcoholic fatty liver disease (NAFLD) in healthy subjects is limited, particularly in Asian populations. This study aimed to investigate the association between HGI and NAFLD in a healthy Korean cohort.

DESIGN

Subjects were stratified in quartiles according to their HGI level. NAFLD was diagnosed by hepatic ultrasonography, hepatic steatosis index and fatty liver index. Multiple logistic regression analysis was performed to evaluate the association between HGI quartiles and the risk of NAFLD.

PATIENTS

Data from subjects without diabetes who underwent liver ultrasonography during routine health examinations were retrospectively reviewed.

RESULTS

Data from 14 465 subjects were included in the analysis. The prevalence of NAFLD increased significantly with each HGI quartile (24.8%, 29.7%, 32.6% and 40.6% in quartiles 1-4, respectively; P < 0.001). In comparison with the lowest HGI quartile group, the highest quartile exhibited worse metabolic parameters, including body weight, waist circumference, body mass index and lipid profiles. Multiple logistic regression analysis adjusted for multiple factors showed that the odds ratio of having NAFLD was 1.564 (95% CI: 1.350-1.813, P < 0.001) in the highest HGI quartile.

CONCLUSIONS

Elevated HGI levels are independently associated with NAFLD in a healthy Asian population.

Glycated albumin is correlated with glycated hemoglobin in type 2 diabetes

Background and aims

Glycated hemoglobin (HbA1c) retrospectively evaluates mean glycemia in the preceding 2–3 months and is the gold standard for assessing glycemic control, while glycated albumin (GA) is currently considered a short to intermediate term integrated glycemic control marker, since it reflects glycemic status over the last 3 weeks. We aimed to investigate the levels of GA, HbA1c and fasting glycemia in a group of patients with type 2 diabetes.

Methods

The observational study included adult type 2 diabetes patients (n=135) according to inclusion and exclusion criteria, randomly selected from Clinical Centre of Diabetes, Cluj-Napoca, Romania. Fasting glycemia, GA, HbA1c and creatinine were measured using commercially available methods.

Results

Of the whole group, 62 (45.9%) were men. Mean age was 62.1±8.6 years old, body mass index was 31.8±6.1 kg/m2 and diabetes duration was 10.0 (4.0; 15.0) years. Fasting glycemia was 162±13.7 mg/dl, GA was 28.0 (21.0; 40.0)% and HbA1c 8.9±2.3%. We found GA was significantly correlated with HbA1c (r=0.19; p=0.029) and fasting glycemia (r=0.32; p<0.001), while HbA1c was significantly correlated with fasting glycemia (r=0.40; p<0.001).

Conclusions

GA was significantly correlated with both HbA1c and fasting glycemia in our patients with type 2 diabetes. While HbA1c is recognized as being the reference test for diabetes control monitoring, GA might a useful biomarker for assessing short to intermediate term glycemic control, particularly important in situations when HbA1c test cannot be reliable or earlier clinical decision making is mandatory.

Adjustment for Waist Circumference Reveals a U-Shaped Association Between Glycated Hemoglobin Levels and Body Mass Index in Young Adults

OBJECTIVES

Body mass index (BMI) is used to assess adiposity worldwide. However, additional adjustment for waist circumference (WC), a surrogate marker of abdominal fat, may be capable of revealing a latent relationship between low body weight and glycated hemoglobin (A1C) concentration. Here, we investigated the relationship between A1C and BMI in young adults, adjusting for WC.

METHODS

We reviewed A1C, BMI, WC and other clinical data in a cross-sectional study of 26,475 apparently healthy Japanese people 20 to 39 years of age who were undergoing health check-ups.

RESULTS

Although the values of most serum parameters were high in subjects with a high BMI in both younger (20 to 29 years of age, n=10,810) and older subjects (30 to 39 years of age, n=15,665), A1C had a J-shaped relationship with BMI category in younger subjects, regardless of sex. A traditional linear model via a generalized linear model showed that in younger subjects, an inverse association of A1C level with BMI category (19 to 26.9 kg/m² vs. ≤18.9 kg/m²) was identified after adjustment for WC. This indicates positive associations between A1C and BMI categories of ≤18.9 (beta=0.06; p<0.0001), 19.0 to 20.9 (beta=0.03; p<0.01) and ≥27.0 kg/m² (beta=0.08; p<0.0001), in contrast to individuals with BMIs of 23.0 to 24.9 kg/m². Similarly, in older subjects, BMIs ≤18.9 kg/m² were associated with A1C levels but to a lesser extent (beta=0.04; p<0.05) than in younger subjects.

CONCLUSIONS

Additional adjustment of BMI for WC revealed a latent U-shaped association between A1C concentration and BMI, particularly in young adults; this deserves further investigation.

Effect of iron deficiency anemia on HbA1c in diabetic patients at Tikur Anbessa specialized teaching hospital, Addis Ababa Ethiopia

Background

Hemoglobin A1C (HbA1c) is the predominant hemoglobin found in HbA1 fractions. A1c assay is the recommended assay for diagnosing diabetes and any condition that changes red cell turnover such as Iron deficiency Anemia (IDA), will lead to spurious A1C results. Therefore, the present study was aimed at determining the effect of IDA on HbA1c in diabetic patients attending Black Lion Specialized Teaching Hospital, Addis Ababa, Ethiopia.

Methods

A facility based comparative cross sectional study was conducted on 174 diabetic patients (87 with IDA and 87 without IDA) from April to July 2016. Socio demographic data and clinical conditions were collected using structured questionnaire. Venous blood was collected for performing Complete blood count (CBC) using Cell dyn 1800 hematology analyzer; Serum ferritin, performed by COBAS INTEGRA 400/800 Chemistry analyzer and HbA1c tests, performed by COBAS C 111 analyzer. Data was analyzed using SPSS version 21 software. Pearson’s correlation, chi-square, and independent t-tests were calculated. The data was presented as mean ± SD. A P-value of < 0.05 was taken as statistically significant.

Results

Mean hemoglobin (Hgb), hematocrit (HCT), Mean cell volume (MCV), mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC) were lower in IDA group compared to non-IDA diabetic patients. HbA1c (%) level was significantly lower in IDA group (6.18 ± 1.57) compared with the non-IDA diabetic patients (7.74 ± 1.81) (p < 0.05).

Conclusion

HbA1c is significantly lower in diabetic patients with IDA compared to the non-IDA diabetic patients. Therefore, the authors believe that monitoring these patients using only HbA1c could be misleading, hence physicians and health care providers should take this into account before making any therapeutic decision. Detailed examination including large number of participants employing advanced laboratory techniques is recommended.

Electronic supplementary material

The online version of this article (10.1186/s12878-018-0132-1) contains supplementary material, which is available to authorized users.

Association between hemoglobin glycation index and cardiometabolic risk factors in Korean pediatric nondiabetic population

PURPOSE

The hemoglobin glycation index (HGI) represents the degree of nonenzymatic glycation and has been positively associated with cardiometabolic risk factors (CMRFs) and cardiovascular disease in adults. This study aimed to investigate the association between HGI, components of metabolic syndrome (MS), and alanine aminotransferase (ALT) in a pediatric nondiabetic population.

METHODS

Data from 3,885 subjects aged 10-18 years from the Korea National Health and Nutrition Examination Survey (2011-2016) were included. HGI was defined as subtraction of predicted glycated hemoglobin (HbA1c) from measured HbA1c. Participants were divided into 3 groups according to HGI tertile. Components of MS (abdominal obesity, fasting glucose, triglycerides, high-density lipoprotein cholesterol, and blood pressure), and proportion of MS, CMRF clustering (≥2 of MS components), and elevated ALT were compared among the groups.

RESULTS

Body mass index (BMI) z-score, obesity, total cholesterol, ALT, abdominal obesity, elevated triglycerides, and CMRF clustering showed increasing HGI trends from lower-to-higher tertiles. Multiple logistic regression analysis showed the upper HGI tertile was associated with elevated triglycerides (odds ratio, 1.65; 95% confidence interval, 1.18-2.30). Multiple linear regression analysis showed HGI level was significantly associated with BMI z-score, HbA1c, triglycerides, and ALT. When stratified by sex, age group, and BMI category, overweight/obese subjects showed linear HGI trends for presence of CMRF clustering and ALT elevation.

CONCLUSION

HGI was associated with CMRFs in a Korean pediatric population. High HGI might be an independent risk factor for CMRF clustering and ALT elevation in overweight/obese youth. Further studies are required to establish the clinical relevance of HGI for cardiometabolic health in youth.

Triglyceride glucose and haemoglobin glycation index for predicting outcomes in diabetes patients with new-onset, stable coronary artery disease: a nested case-control study

AIM

Previous studies have shown that both triglyceride glucose (TyG) and haemoglobin glycation indexes (HGI) are predictors of cardiovascular risk. However, the prognostic value of TyG index and HGI in patients with type 2 diabetes mellitus (T2DM) and stable coronary artery disease (CAD) is not determined.

METHODS

We conducted a nested case-control study among 1282 T2DM patients with stable CAD. Patients were followed up for 3846 person-years. A total of 160 patients with events (12.5%) were identified and matched individually on age, gender, previous use of lipid lowering agents and duration of follow-up with 640 controls.

RESULTS

In Kaplan-Meier analysis, the upper tertiles of TyG index and HGI had a significant lower event-free survival (p = .002; p = .036, respectively). Of the note, both TyG index and HGI were associated with increased risk of MACCEs after adjusting for confounding risk factors [adjusted HR (95% CI): 1.693 (1.238-2.316); 1.215 (1.046-1.411), respectively]. Moreover, adding TyG index to the Cox model increased the C-statistic to 0.638 (95%CI: 0.595-0.683, p = .002) while the C-statistic was not statistically improved when HGI was included (p = .240).

CONCLUSIONS

Both TyG index and HGI could predict cardiovascular outcomes in T2DM patients with new-onset, stable CAD while TyG index might be better. Key messages Both TyG and HGI are predictors of cardiovascular risk. The prognostic value of TyG index and HGI in T2DM patients with stable coronary artery disease is not determined. Our study firstly indicates that TyG index might have better prognostic value than HGI in T2DM patients with new-onset, stable CAD.

Effect of iron supplementation on HbA1c levels in pregnant women with and without anaemia

BACKGROUND

Iron deficiency anaemia has been associated with higher HbA1c levels. However, during and after iron supplementation there is a decrease in HbA1c results, causing a misinterpretation. Our aim was to analyse the effect of iron supplementation on HbA1c levels in nondiabetic pregnant women with and without anaemia.

METHODS

Pregnant women in prenatal care, without gestational diabetes (GDM) or previous diabetes mellitus (DM) that performed an oral glucose tolerance test (OGTT) in the third trimester of pregnancy were invited to participate. Clinical and laboratorial analyses were performed, including standardized questionnaire, OGTT, full blood count and HbA1c.

RESULTS

A total of 231 pregnant women without DM or GDM were included in the study. According to anaemia and/or iron supplementation, we divided women in: no iron and no anaemia - Group 1 (N=86); no iron and with anaemia - Group 2 (N=29); iron and no anaemia - Group 3 (N=87); iron and anaemia - Group 4 (N=29). There was statistically a significant, although no clinically relevant, difference between HbA1c values in pregnant women in Groups 1 and 4 [5.1±0.4% (32±4.4mmol/mol) and 4.8±0.3% (29±3.3mmol/mol), P<0.01; respectively]. HbA1c values in pregnant women in Groups 1, 2 and 3 were similar, independently of anaemia [5.1±0.4% (32±4.4mmol/mol); 5.0±0.4% (31±4.4mmol/mol) and 5.0±0.4% (31±4.4mmol/mol); p>0.05; respectively].

CONCLUSIONS

Iron supplementation during pregnancy does not affect HbA1c levels and has no clinical impact in the final interpretation of results in the absence of anaemia or presence of mild anaemia. Interpreting HbA1c results in pregnant women during iron therapy and with moderate or severe anaemia still requires caution.

Association Between Coronary Artery Calcification and the Hemoglobin Glycation Index: The Kangbuk Samsung Health Study

CONTEXT

The hemoglobin glycation index (HGI) is known to be correlated with the risk for cardiovascular disease.

OBJECTIVE

To analyze the association between incident coronary artery calcification (CAC) and the changes in HGI among participants without diabetes, over 4 years.

DESIGN, SETTING, PARTICIPANTS, AND OUTCOME MEASURES

A retrospective study of 2052 nondiabetic participants in whom the coronary artery calcium score was measured repeatedly over 4 years, as part of a health checkup program in Kangbuk Samsung Hospital in Korea, and who had no CAC at baseline. The HGI was defined as the difference between the measured and predicted hemoglobin A1c (HbA1c) levels.

RESULTS

A total of 201 participants developed CAC after 4 years, and the mean baseline HGI was significantly higher in those patients. The incidence of CAC gradually increased from the first to the fourth quartile groups of baseline HGI. The odds ratio (OR) for incident CAC was the highest among the four groups divided by the quartiles of the baseline HGI and was significant after adjustment for confounding variables (vs first quartile group: OR, 1.632; 95% confidence interval, 1.024 to 2.601). The incidence of and risk for CAC development were significantly higher than in other groups compared with the low-to-low group after adjustment for confounding factors; however, when baseline HbA1c level was included in the model, only participants with a low-to-high HGI over 4 years showed a significantly increased OR for CAC development compared with the low-to-low group (OR, 1.722; 95% confidence interval, 1.046 to 2.833).

CONCLUSIONS

The participants with a high baseline HGI and consistently high HGI showed a higher risk for incident CAC than those with a low baseline HGI. An increased HGI over 4 years significantly increased the risk for CAC regardless of the baseline HbA1c levels.

Anemia in diabetes: Experience of a single treatment center in Kuwait

AIMS

Diabetes mellitus is the most common metabolic disorder in Kuwait. Anemia is a known outcome of diabetes and its related complications. This study examined the prevalence of anemia in diabetic subjects in Kuwait as well as any association between the presence of anemia with Hemoglobin A_1c and diabetes complications.

METHODS

The study subjects were diabetic patients with complete records and two or more visits at Dasman Diabetes Institute. Patient's data included demographics, complications, medications and laboratory results. Descriptive statistics were applied using SPSS.

RESULTS

Of 1580 included diabetic patients; the prevalence of anemia was 28.5% (95% CI: 26.3, 30.8). Diabetic females had a higher rate of anemia compared to males (35.8% vs. 21.3% respectively, p<0.001). There was no association between diabetes control (HbA_1c) and anemia in both genders (p=0.887). Patients with elevated serum creatinine and microalbuminuria were more likely to be anemic (p<0.001). Diabetic patients with anemia had higher presence of peripheral neuropathy and diabetic foot (p<0.001).

CONCLUSION

This study shows high prevalence of anemia in diabetic patients, particularly in those with diabetic complications. These results should prompt treatment centers to include anemia investigation and management within their diabetes treatment protocols to reduce morbidity in diabetes.

Oxidized LDL but not total LDL is associated with HbA1c in individuals without diabetes

OBJECTIVE

This study investigates the association between HbA1c, LDL and oxi-LDL in individuals without diabetes (DM).

METHODS

One hundred and ninety-six individuals, without DM, were enrolled and divided into three groups according to HbA1c and fasting plasma glucose values. HbA1c, oxi-LDL, LDL, and other biochemical measurements of lipid profile were also carried out.

RESULTS

oxi-LDL levels showed significant differences among all groups and group 3 presented higher values [34U/L (27-46); 44U/L (37-70); and 86U/L (49-136); p<0.001; for groups 1, 2 and 3, respectively]. There was also a significant difference in oxi-LDL/HDL and oxi-LDL/LDL ratios among all groups (p<0.001). There was no significant difference in total cholesterol (TC), triglycerides and LDL values among groups. HbA1c showed moderate positive associations with oxi-LDL (r=0.431; p<0.001), oxi-LDL/HDL ratio (r=0.423, p<0.001), and oxi-LDL/LDL ratio (r=0.359, p<0.001). There were lower associations between HbA1c and TC (r=0.142; p=0.048), triglycerides (r=0.155; p=0.030), LDL (r=0.148; p=0.039), non-HDL (r=0.192; p=0.007) and Apo B (r=0.171, p<0.001). The positive associations between HbA1c and oxi-LDL, oxi-LDL/HDL and oxi-LDL/LDL ratios remained significant even after adjustment by multiple linear regression analysis for the variables alcohol consumption, use of medicine, BMI, and age.

CONCLUSIONS

oxi-LDL levels are significantly associated with HbA1c in non-diabetic individuals. However, the levels of traditional atherogenic lipids only showed a weak association with HbA1c levels. Those at high risk of developing DM or cardiovascular disease have higher levels of oxi-LDL. These data favor to the use of HbA1c as a biomarker to identify individuals at risk of developing complications even in non-diabetic glycemic levels.

Glycated albumin: a potential biomarker in diabetes

Diabetes mellitus (DM) is a chronic and metabolic disease that presents a high global incidence. Glycated hemoglobin (A1C) is the reference test for long-term glucose monitoring, and it exhibits an association with diabetic chronic complications. However, A1C is not recommended in clinical situations which may interfere with the metabolism of hemoglobin, such as in hemolytic, secondary or iron deficiency anemia, hemoglobinopathies, pregnancy, and uremia. The glycated albumin (GA) is a test that reflects short-term glycemia and is not influenced by situations that falsely alter A1C levels. GA is the higher glycated portion of fructosamine. It is measured by a standardized enzymatic methodology, easy and fast to perform. These laboratory characteristics have ensured the highlight of GA in studies from the last decade, as a marker of monitoring and screening for DM, as well as a predictor of long-term outcomes of the disease. The aim of this review was to discuss the physiological and biochemistry characteristics of the GA, as well as its clinical utility in DM.

Effect of ethnicity on HbA1c levels in individuals without diabetes: Systematic review and meta-analysis

Aims/Hypothesis

Disparities in HbA1c levels have been observed among ethnic groups. Most studies were performed in patients with diabetes mellitus (DM), which may interfere with results due to the high variability of glucose levels. We conducted a systematic review and meta-analysis to investigate the effect of ethnicity on HbA1c levels in individuals without DM.

Methods

This is a systematic review with meta-analysis. We searched MEDLINE and EMBASE up to September 2016. Studies published after 1996, performed in adults without DM, reporting HbA1c results measured by certified/standardized methods were included. A random effects model was used and the effect size was presented as weighted HbA1c mean difference (95% CI) between different ethnicities as compared to White ethnicity.

Results

Twelve studies met the inclusion criteria, totalling data from 49,238 individuals. There were significant differences between HbA1c levels in Blacks [0.26% (2.8 mmol/mol); 95% CI 0.18 to 0.33 (2.0 to 3.6), p <0.001; I² = 90%, p <0.001], Asians [0.24% (2.6 mmol/mol); 95% CI 0.16 to 0.33 (1.7 to 3.6), p <0.001; I² = 80%, p = 0.0006] and Latinos [0.08% (0.9 mmol/mol); IC 95% 0.06 to 0.10 (0.7 to 1.1); p <0.001; I² = 0%; p = 0.72] when compared to Whites.

Conclusions/Interpretation

This meta-analysis shows that, in individuals without DM, HbA1c values are higher in Blacks, Asians, and Latinos when compared to White persons. Although small, these differences might have impact on the use of a sole HbA1c point to diagnose DM in all ethnic populations.

A1C Combined With Glycated Albumin Improves Detection of Prediabetes in Africans: The Africans in America Study

OBJECTIVE

Slowing the diabetes epidemic in Africa requires improved detection of prediabetes. A1C, a form of glycated hemoglobin A, is recommended for diagnosing prediabetes. The glycated proteins, fructosamine and glycated albumin (GA), are hemoglobin-independent alternatives to A1C, but their efficacy in Africans is unknown. Our goals were to determine the ability of A1C, fructosamine, and GA to detect prediabetes in U.S.-based Africans and the value of combining A1C with either fructosamine or GA.

RESEARCH DESIGN AND METHODS

Oral glucose tolerance tests (OGTT) were performed in 217 self-identified healthy African immigrants (69% male, age 39 ± 10 years [mean ± SD], BMI 27.6 ± 4.5 kg/m(2)). A1C, fructosamine, and GA were measured. Prediabetes was diagnosed by American Diabetes Association criteria for glucose obtained from a 2-h OGTT. The thresholds to diagnose prediabetes by A1C, fructosamine, and GA were the cutoff at the upper tertile for each variable: ≥5.7% (39 mmol/mol) (range 4.2-6.6% [22.4-48.6 mmol/mol]), ≥230 µmol/L (range 161-269 µmol/L), and ≥13.35% (range 10.20-16.07%), respectively.

RESULTS

Prediabetes occurred in 34% (74 of 217). The diagnostic sensitivities of A1C, fructosamine, and GA were 50%, 41%, and 42%, respectively. The P values for comparison with A1C were both >0.3. Combining A1C with either fructosamine or GA increased sensitivities. However, the sensitivity of A1C combined with fructosamine was not better than for A1C alone (72% vs. 50%, P = 0.172). In contrast, the sensitivity of A1C combined with GA was higher than for A1C alone (78% vs. 50%, P < 0.001).

CONCLUSIONS

As individual tests, A1C, fructosamine, and GA detected ≤50% of Africans with prediabetes. However, combining A1C with GA made it possible to identify nearly 80% of Africans with prediabetes.

Effect of iron deficiency anaemia on HbA1c levels is dependent on the degree of anaemia

OBJECTIVES

Studies suggest that iron deficiency anaemia (IDA) is associated with higher HbA1c levels. We conducted a control–case study to investigate the effect of IDA on HbA1c levels, measured by two commonly used methods, in non-diabetic individuals.

DESIGN AND METHODS

A total of 122 patients were included, 61 patients with IDA and 61 patients without anaemia. HbA1c was measured by both ion exchange HPLC Variant II Turbo BioRad and immunoturbidimetry (IT) Tina Quant II Roche Diagnostics in each sample. HbA1c results were compared between groups. For correlation analysis, patients were considered altogether.

RESULTS

There was a significant difference between the results of HbA1c in patients with IDA [HPLC 5.6 ± 0.4% (38 ± 4.4 mmol/mol) and IT 5.7 ± 0.4% (39 ± 4.4 mmol/mol)] and those measured in patients without anaemia [HPLC 5.3 ± 0.4% (34 ± 4.4 mmol/mol) and IT 5.3 ± 0.3% (34 ± 3.3 mmol/mol)], (p < 0.001). Significant negative correlations were observed between total haemoglobin (Hb), haematocrit, mean corpuscular volume (MCV) and ferritin with HbA1c values measured by IT (r = − 0.557; r = − 0.539; r = − 0.488; r = − 0.499; p < 0.01; respectively). These negative correlations were weaker with HbA1c measured by HPLC (r = − 0.272; r = − 0.250; r = − 0.273; r = − 0.229 for Hb, haematocrit, MCV and ferritin; p < 0.05; respectively). HbA1c results were higher in patients with moderate and severe anaemia. However mild anaemia did not show significant effects on HbA1c results measured by both methods.

CONCLUSIONS

IDA affects HbA1c results and this effect is dependent on anaemia degree. These upward changes are statistically significant but they may be not clinically relevant when the overall variability of the HbA1c test is considered. The presence of slight anaemia is likely to have a minor effect on HbA1c levels favouring its use to diagnose diabetes in patients with mild anaemia.