Influence of iron metabolism indices on HbA1c in non-diabetic pregnant women with and without iron-deficiency anemia: effect of iron supplementation

Exploring the Impact of Iron Deficiency Anaemia on Glycated Haemoglobin A1c Levels in Pregnant and Non-Pregnant Women: A Systematic Review

Haemoglobin A1C (HbA1c) is fundamental in monitoring glycaemic control during pregnancy. However, several conditions could affect this test's accuracy, including iron deficiency anaemia (IDA). Hence, this systematic review delves into the underexplored connection between IDA, iron replacement therapy (IRT), and haemoglobin A1C (HbA1c) during pregnancy. An electronic search of the Cochrane, MEDLINE, and Embase databases was conducted by six authors. From a comprehensive search strategy, 968 records were obtained. After applying the inclusion and exclusion criteria, seven studies were included, comprising 365 women selected for analysis. Six studies indicated a positive correlation between IDA and HbA1c levels, while one found no correlation. The average HbA1c level of the included studies in pregnant women was 5.64%. In comparison, it was found that non-pregnant women had lower HbA1c levels. Among the included studies, the mean HbA1c levels decreased from 5.1% to 4.89% after treating pregnant women with IRT. The review emphasises the complexity of interpreting HbA1c levels in pregnant women with IDA, highlighting the influence of pregnancy-induced physiological changes. In addition, this suggests that HbA1c should not be the sole criterion for diabetes management in pregnant women with IDA. Future research should focus on alternative glycaemic monitoring methods unaffected by IDA.

Early postpartum HbA1c after hyperglycemia first detected in pregnancy-Imperfect but not without value

BACKGROUND

South African women of childbearing age are disproportionally affected by obesity and at significant risk of Type 2 Diabetes Mellitus (T2DM). Unless pregnant, they do not readily undergo screening for T2DM. With a local focus on improved antenatal care, hyperglycemia is often first detected in pregnancy (HFDP). This may erroneously be attributed to Gestational Diabetes Mellitus (GDM) in all without considering T2DM. Glucose evaluation following pregnancy is essential for early detection and management of women with T2DM in whom persistent hyperglycemia is to be expected. Conventional testing with an oral glucose tolerance test (OGTT) is cumbersome, prompting investigation for alternate solutions.

AIM

To compare the diagnostic performance of HbA1c to the current gold standard OGTT in women with HFDP 4-12 weeks post-delivery.

METHODS

Glucose homeostasis was assessed with OGTT and HbA1c in 167 women with HFDP, 4-12 weeks after delivery. Glucose status was based on American Diabetes Association criteria.

RESULTS

Glucose homeostasis was assessed at 10 weeks (IQR 7-12) after delivery. Of the 167 participants, 52 (31%) had hyperglycemia, which was comprised of 34 (20%) prediabetes and 18 (11%) T2DM. Twelve women in the prediabetes subgroup had diagnostic fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG), but in two-thirds of the patients (22/34) only one time point proved diagnostic. The FPGs and the 2hPGs of six women with HbA1c-based T2DM were both within the prediabetes diagnostic range. According to the HbA1c measurements, 85% of 52 participants with gold standard OGTT defined hyperglycemia (prediabetes and T2DM) as well as 15 of 18 women with postpartum persistent T2DM were correctly classified. According to FPG, 15 women with persistent hyperglycemia would have been missed (11 with prediabetes and four with T2DM; 29%). When compared to an OGTT, a single HbA1c of 6.5% (48mmol/mol) postpartum demonstrated a sensitivity of 83% and specificity of 97% for the identification of T2DM.

CONCLUSION

HbA1c may improve access to postpartum testing in overburdened clinical settings where the required standards of OGTT cannot be guaranteed. HbA1c is a valuable test to detect women who will benefit most from early intervention but cannot unequivocally replace OGTT.

Effect of thiamine supplementation on glycaemic outcomes in adults with type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Patients with type 2 diabetes mellitus (T2DM) have been shown to have thiamine deficiency. Dietary supplementation is an economic strategy to control blood glucose. Objective: To evaluate effectiveness of thiamine supplementation on glycaemic outcomes in patients with T2DM.

METHODS

Eligibility criteria: Studies that assessed effect of thiamine supplementation in adults with T2DM which measured glycaemic outcomes-HbA1c, fasting blood glucose (FBG) and/or postprandial blood glucose (PPG) were included. Information sources: PUBMED, Tripdatabase, the Cochrane Central Register, National Institute of Health Clinical Database and Google Scholar were searched until December 2021 for RCTs. Risk of bias: It was assessed using standardised critical appraisal instruments from the Joanna Briggs Institute for RCTs. Synthesis of results: Where possible, studies were pooled in a meta-analysis. Results were presented in a narrative format if statistical pooling was not possible.

RESULTS

Included studies: Six trials involving 364 participants. Synthesis of results: No significant beneficial effects were observed on glycaemic outcomes with 100-900 mg/day of thiamine or benfotiamine for up to 3 months (HbA1c: MD, -0.02%, 95% CI: -0.35 to 0.31; FBG: MD,-0.20 mmol/L; 95% CI: -0.69 to 0.29; PPG: MD, - 0.20 mmol/L, 95% CI: -2.05 to 1.65 (mean difference, MD)). There was a significant increase in high-density lipoprotein (HDL) (MD, 0.10; 95% CI: 0.10 to 0.20) at 3-month follow-up. Benfotiamine reduced triglyceride level (MD, -1.10; 95% CI: -1.90 to -0.30) in 120 mg/day dose as compared with placebo 150 mg/day, however this was not demonstrated in higher doses.

DISCUSSION

Limitations of evidence: Inclusion of single-centre trials published only in English, small sample sizes of included studies, lack of trials investigating outcomes for same comparisons and varying follow-up periods. Interpretation: Thiamine supplementation does not affect glycaemic outcomes, however reduces triglycerides while increasing HDL. Multicentre well-designed RCT with higher doses of thiamine and a follow-up period of 1-2 years will provide better evidence.

PROSPERO REGISTRATION NUMBER

CRD42020170520.

Effect of anemia and erythrocyte indices on hemoglobin A1c levels among pregnant women

BACKGROUND

Anemia is a common disorder among pregnant women; however, the effect of anemia on hemoglobin A1c (HbA1c) levels has not been adequately explored. We aim to examine the influence of anemia on the HbA1c concentration and investigate the relationship between erythrocyte indices and HbA1c levels during pregnancy.

METHODS

We performed a retrospective analysis of 1369 pregnant Chinese women. The clinical and analytical data were collected. Independent t-test and Analysis of Variance were used for comparative studies, and multiple linear regression analysis was used to identify the association between erythrocyte indices and HbA1c.

RESULTS

The differences in HbA1c between non-anemia and mild anemia were negligible, and the differences in HbA1c between non-anemia and moderate anemia were well within the allowable variability for clinical practice (≥0.5% absolute changes). Mean corpuscular hemoglobin (MCH) correlated with HbA1c significantly, independent of pregnancy, trimester, and anemia. The distinction of HbA1c levels between grades of Hb became no significant (P = 0.955), while differences between trimesters persisted after adjusting for MCH.

CONCLUSION

Mild and moderate anemia should not be the primary concern when using HbA1c to monitor blood glucose in pregnancy. MCH showed negative correlations with HbA1c independently, suggesting a previously unknown mechanism affecting HbA1c levels.

The substantial burden of non-communicable diseases and HIV-comorbidity amongst adults: Screening results from an integrated HIV testing services clinic for adults in Soweto, South Africa

BACKGROUND

South Africa is disproportionately impacted by non-communicable diseases (NCDs) and HIV/AIDS. We investigated the prevalence of known/unknown NCD risk factors, HIV, and NCD risk factor-HIV comorbidity; and treatment status on known diseases to determine the prevalence of controlled/uncontrolled disease.

METHODS

This cross-sectional study (June 2018-March 2019) within an integrated testing centre in Soweto, South Africa, screened adults (aged ≥18 years) for body mass index (BMI), hypertension (HT), rapid glucose and cholesterol, and HIV. Results were stratified by age group, sex, HIV-status, and self-reported ART use. Analysis included Fisher's exact, chi-squared, Kruskal Wallis, and Student's T-tests.

FINDINGS

Of 780 enrolled participants, 19.2% were HIV-positive, 37.5% were overweight/obese, 18.0% hypertensive, 10.8% hyperglycaemic, and 8.1% had hypercholesterolaemia. Significantly more women had overweight/obese BMI than men (46.8% vs 19.7%; p<0.0001), and women aged 25-34 years had significantly more hypercholesterolaemia than same-aged men (18.2% vs 5.6%; p = 0.02). HIV-positive participants had significantly more hyperglycaemia than HIV-negative participants (16.1% vs 9.6%; p = 0.02), and those on ART (63.9%) had significantly more hypercholesterolaemia than those not on ART (21.7% vs. 4.9%; p = 0.002). Of participants with HT, hyperglycaemia, and hypercholesterolaemia; 72.4%, 96.1%, and 93.3% were newly diagnosed. All participants with previously diagnosed NCDs remained with uncontrolled disease.

INTERPRETATION

There is a high burden of HIV, NCD risk factors, and comorbidity in Soweto, and amongst young adults (18-34 years), especially women. Lowering age requirements for glucose/cholesterol screening to 18+ years, regardless of BMI, HIV-status, or ART use, may yield timely NCD diagnosis/management.

Should HbA1C be used to screen pregnant women for undiagnosed diabetes in the first trimester? A review of the evidence

BACKGROUND

Diabetes in pregnancy is associated with miscarriage, stillbirth, congenital abnormalities, macrosomia and perinatal mortality. The demographics of the population becoming pregnant has changed (more obese and older women). More women are therefore entering pregnancy with undiagnosed diabetes.

AIM

To review the literature on HbA1c as a screening tool to identify undiagnosed diabetes in the first trimester of pregnancy.

METHODS

A systematic search of the evidence was undertaken using specific search criteria from Cochrane Library, EMBASE, Medline, NICE Guidance, PROSPERO and PubMed. The initial search identified 319 papers, based on the inclusion and exclusion criteria eight papers were critically appraised.

RESULTS

There is limited evidence on the use of HbA1c as a screening tool for undiagnosed diabetes in the literature during the first trimester of pregnancy. Although HbA1c is considered a useful test for diabetes in the non-pregnant population the hormonal and metabolic changes that occur in pregnancy mean that there are many limitations in pregnancy. Furthermore, HbA1c levels are affected by iron deficiency which is common in pregnancy.

CONCLUSIONS AND RECOMMENDATIONS

There is insufficient evidence to suggest a change in practice to include offering HbA1c screening for undiagnosed diabetes in the first trimester.

Use of glycated albumin for the identification of diabetes in subjects from northeast China

BACKGROUND

Metabolic memory is important for the diagnosis and treatment of diabetes in the early stage, and in maintaining blood glucose concentrations within the normal range. The clinical diagnosis of diabetes mellitus is currently made using fasting plasma glucose, 2 h-plasma glucose (2h-PG) during a 75 g oral glucose tolerance test, and hemoglobin A1c (HbA1c) level. However, the fasting plasma glucose test requires fasting, which is a barrier to screening, and reproducibility of the 2h-PG level is poor. HbA1c is affected by a shortened red blood cell lifespan. In patients with anemia and hemoglobinopathies, the measured HbA1c levels may be inaccurate. Compared with HbA1c, glycated albumin (GA) is characterized by more rapid and greater changes, and can be used to diagnose new-onset diabetes especially if urgent early treatment is required, for example in gestational diabetes. In this study, we provided cutoff values for GA and evaluated its utility as a screening and diagnostic tool for diabetes in a large high-risk group study.

AIM

To evaluate the utility of GA in identifying subjects with diabetes in northeast China, and to assess the diagnostic accuracy of the proposed GA cutoff in the diagnosis of diabetes mellitus.

METHODS

This cross-sectional study included 1935 subjects, with suspected diabetes or in high-risk groups, from 2014 to 2015 in the Second Affiliated Hospital of Harbin Medical University (Harbin, China). The use of GA to identify diabetes was investigated using the area under the receiver operating characteristic curve (AUC). The GA cutoffs were derived from different 2h-PG values with hemoglobin A1c cutoffs used as a calibration curve.

RESULTS

The GA cutoff for the diagnosis of diabetes mellitus was 15.15% from the receiver operating characteristic (ROC) curve. ROC analysis demonstrated that GA was an efficient marker for detecting diabetes, with an AUC of 90.3%.

CONCLUSION

Our study supports the use of GA as a biomarker for the diagnosis of diabetes.

The use of longitudinal hemoglobin A1c values to predict adverse obstetric and neonatal outcomes in pregnancies complicated by pregestational diabetes

BACKGROUND

Although an elevated early pregnancy hemoglobin A1c has been associated with both spontaneous abortion and congenital anomalies, it is unclear whether A1c assessment is of value beyond the first trimester in pregnancies complicated by pregestational diabetes.

OBJECTIVE

We sought to investigate the prognostic ability of longitudinal A1c assessment to predict obstetric and neonatal adverse outcomes based on degree of glycemic control in early and late pregnancy.

MATERIALS AND METHODS

This was a retrospective cohort study of all pregnancies complicated by pregestational diabetes from January 2012 to December 2016 at The Ohio State University Wexner Medical Center with both an early A1c (<20 weeks' gestation) and late A1c (>26 weeks' gestation) available for analysis. Patients were categorized by good (early and late A1c <6.5%), improved (early A1c >6.5% and late A1c <6.5%) and poor (late A1c >6.5%) glycemic control. A multivariate regression model was used to calculate adjusted odds ratios (aOR) for each identified obstetric and neonatal outcome, controlling for maternal age, body mass index, race/ethnicity, type of diabetes, and gestational age at delivery compared to good control as the referent group.

RESULTS

A total of 341 patients met inclusion criteria during the study period. The median A1c values improved from early to late gestation in the good (5.7% [interquartile range [IQR], 5.4-6.1%] versus 5.4%; [IQR 5.2-5.7%]), improved (7.5% [IQR, 6.7-8.5] versus 5.9% [IQR, 5.6-6.1%]) and poor (8.3% [IQR, 7.1-9.6%] versus 7.3% [IQR, 6.8-7.9%]) glycemic control groups. There were no statistically significant differences in the rate of adverse outcomes between the good and improved groups except for an increased rate of neonatal intensive care unit admissions in the improved group (aOR, 3.7; confidence interval [CI], 1.9-7.3). In contrast, the poor control group had an increased rate of shoulder dystocia (aOR, 6.8; CI, 1.4-34.0), preterm delivery (aOR, 3.9; CI, 2.1-7.3), neonatal intensive care unit admission (aOR, 2.8; CI, 1.4-5.3), respiratory distress syndrome (aOR, 3.0; CI, 1.1-8.0), hypoglycemia (aOR, 3.2; CI, 1.5-6.9), large for gestational age weight at birth (aOR, 2.7; CI, 1.5-4.9), neonatal length of stay >4 days (aOR, 3.1; CI, 1.6-6.0) and preeclampsia (aOR, 2.4; CI, 1.2-4.6). There were no differences in rates of cesarean delivery, umbilical artery pH <7.1, or Apgar score <7 at 5 minutes after regression analysis.

CONCLUSION

Antenatal hemoglobin A1c values are useful for objective risk stratification of patients with pregestational diabetes. Strict glycemic control throughout pregnancy with a late pregnancy A1c target of <6.5% leads to reduced rates of obstetric and neonatal adverse outcomes independent of early pregnancy glucose control.

HbA1c: a review of non-glycaemic variables

Identification of the correlation between HbA1c and diabetic complications has yielded one of the most clinically useful biomarkers. HbA1c has revolutionised the diagnosis and monitoring of diabetes mellitus. However, with widespread adoption of HbA1c has come increasing recognition that non-glycaemic variables can also affect HbA1c, with varying clinical significance. Furthermore, the identification of a discrepancy between predicted and measured HbA1c in some individuals, the so-called 'glycation gap', may be clinically significant. We aimed to review the current body of evidence relating to non-glycaemic variables to quantify any significance and provide subsequent suggestions. A PubMed-based literature search was performed, using a variety of search terms, to retrieve articles detailing the non-glycaemic variables suggested to affect HbA1c. Articles were reviewed to assess the relevance of any findings in clinical practice and where possible guidance is given. A range of non-glycaemic variables have statistically significant effects on HbA1c. While the clinical implications are generally irrelevant, a small number of non-glycaemic variables do have clinically significant effects and alternative biomarkers should be considered instead of, or in addition to, HbA1c. There are a small number of non-glycaemic variables which have a clinically significant effect on HbA1c, However, the vast majority of non-glycaemic variables have no clinical relevance. While clinicians should have an awareness of those non-glycaemic variables with clinical significance, in the vast majority of clinical scenarios HbA1c should continue to be used with confidence.

Calcium dobesilate: A drug treatment for diabetic retinopathy can negatively interfere with the measurement of glycated albumin using the enzymatic method

BACKGROUND

We reported that calcium dobesilate, a vasoprotective agent mainly used for diabetic retinopathy (DR), negatively interferes with glycated albumin (GA) assays involving enzymatic methods.

METHODS

A calcium dobesilate standard was added to 3serum pools in vitro to prepare concentration-response series according to Clinical and Laboratory Standards Institute EP7-A2 guidelines. Percentage deviation between each drug concentration and the drug-free sample was calculated for 6 commercially available GA assays. The acceptable limit of deviation for GA was ±5.61%. For in vivo analyses, changes in serum concentrations of GA and calcium dobesilate were monitored in eight healthy participants before and after oral calcium dobesilate administration.

RESULTS

At 16 μg/ml calcium dobesilate, within the therapeutic range, the percentage deviations for Asahi Kasei, Maccura, Leadman, Homa, and Medicalsystem assays were -8.7% to -49.7%, -2.0% to -47.7%, and -10.1% to -35.7% for low-, medium- and high-GA level interference pools, respectively, exhibiting dose-dependent negative interference. In vivo, calcium dobesilate ingestion was associated with statistically significant, falsely decreased measurements in 5 GA assays, 2 h after daily 500 mg administration.

CONCLUSIONS

Calcium dobesilate ingestion was associated with erroneously low measurements in 5 GA assays. The degree of interference varied greatly among the assays examined.

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.

Effect of treatment of iron deficiency anemia onhemoglobin A1c in type 2 diabetic patients

Background/aim: Iron deficiency anemia (IDA) affects hemoglobin A1c (HbA1c) levels. This study aimed to evaluate the effect of treatment of iron deficiency anemia on hemoglobin A1c in type 2 diabetic patients.Materials and methods: Ninety type 2 diabetes mellitus (T2DM) patients with IDA were included in a randomized, placebo-controlled, single-blind clinical trial. The intervention group (n = 45) received 200 mg/day oral iron for 3 months and the control group (n = 45) received an oral placebo for the same period. Fasting blood sugar, complete blood count, and HbA1c were measured for all subjects at the beginning and the end of the trial.Results: The mean age of the treatment and control group was 51.47 ± 1.05 and 52 ± 1.1 years, respectively. The two groups were not statistically significantly different with regard to diabetes duration (P = 0.436) and age (P = 0.617). Hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin, serum iron, ferritin, total iron-binding capacity, and HbA1c were significantly improved in the intervention group in comparison with the control group (P = 0.005).Conclusion: Iron status should be considered during the interpretation of the HbA1c concentrations in diabetes mellitus. Iron replacement therapy can decrease HbA1c in anemic patients with IDA and T2DM.

Iron deficiency anemia and glucose metabolism

Iron deficiency anemia (IDA) is a global public health problem affecting both developing and developed countries with major consequences for human health as well as social and economic development. It occurs at all stages of the life cycle, but is more prevalent in pregnant women and young children. IDA appears to be more common in diabetic patients compared to non-diabetic population. Iron deficiency (ID) and IDA can impair glucose homeostasis in animals and human and may negatively affect glycemic control and predispose to more complications in diabetic patients. On the other hand diabetes and its complications are associated with anemia and its correction improves diabetes control and may prevent or delay the occurrence of complications. Physicians treating this form of anemia should be aware of its negative effect on glycemic control in normal and diabetic patients (both type 1 and type 2). They should prevent ID and treat early all those with IDA.This brief review aims to enlighten the different effects of IDA on glucose metabolism in normal and diabetic patients.

Is There a Role for HbA1c in Pregnancy?

Outside pregnancy, HbA1c analysis is used for monitoring, screening for and diagnosing diabetes and prediabetes. During pregnancy, the role for HbA1c analysis is not yet established. Physiological changes lower HbA1c levels, and pregnancy-specific reference ranges may need to be recognised. Other factors that influence HbA1c are also important to consider, particularly since emerging data suggest that, in early pregnancy, HbA1c elevations close to the reference range may both identify women with underlying hyperglycaemia and be associated with adverse pregnancy outcomes. In later pregnancy, HbA1c analysis is less useful than an oral glucose tolerance test (OGTT) at detecting gestational diabetes. Postpartum, HbA1c analysis detects fewer women with abnormal glucose tolerance than an OGTT, but the ease of testing may improve follow-up rates and combining HbA1c analysis with fasting plasma glucose or waist circumference may improve detection rates. This article discusses the relevance of HbA1c testing at different stages of pregnancy.

Role of HbA1c in predicting risk for congenital malformations

AIMS

Association between conventionally identified hyperglycemias and rates of congenital abnormalities is known; however there is less information about role of HbA1c in determining gestational hyperglycemias and associated risks. This study tried to explore the association between HbA1c in women without known diabetes at first antenatal visit and risk of congenital malformations (CM) among Saudi women living at Al-Madinah Al-Monawarah.

METHODS

Eleven hundred and eighty (1180), healthy, first-trimester pregnant Saudi females without known diabetes, were selected from various antenatal care clinics of Al-Madinah Al-Monawarah city. General clinical and biochemical data was collected for this study by researchers at first visit and the time of delivery.

RESULTS

Nearly one fifth (19.6%) of mothers had above normal HbA1c (>5.7) at first visit. Rates of CM had significant positive association with level of HbA1c. Rate of CM among those who had HbA1c in diabetes range, pre-diabetes range or normal range was 27.8%, 9.8% and 3.0%, respectively. The difference was significant between normal and pre-diabetes at the level P=0.000 and between pre-diabetes and diabetes at level P=0.038.

CONCLUSION

In this study HbA1c is found to be a valuable predictor of risk of congenital malformations. This observation calls for further studies and establishment of policies for care of pregnant mothers having higher than normal HbA1c at first visit.

Intake of Vitamin and Mineral Supplements and Longitudinal Association with HbA1c Levels in the General Non-Diabetic Population--Results from the MONICA/KORA S3/F3 Study

Background

Lower levels of hemoglobin A_1c (HbA_1c) are associated with a decreased risk of cardiovascular complications in diabetic and non-diabetic individuals. The aim of the study was to longitudinally investigate the association between the use of 11 vitamins and minerals (vitamins E, C, D, B₁, folic acid, carotenoids, calcium, magnesium, zinc, iron, and selenium) and change in HbA_1c levels over 10 years in non-diabetic individuals drawn from the general population.

Methods

Baseline data were available from 4447 subjects included in the population-based “Monitoring of Trends and Determinants in Cardiovascular Diseases” (MONICA) Augsburg S3 survey (1994/95). Follow-up data were derived from 2774 participants in the follow-up survey named “Cooperative Health Research in the Region of Augsburg” (KORA) F3 (2004/05). Vitamin/mineral intake from supplements and medications was assessed in a personal interview, where participants were asked to bring product packages of preparations that had been ingested during the last 7 days prior to the examination. Associations between regular vitamin/mineral intake amounts and HbA_1c levels measured at baseline and follow-up were investigated using generalized estimating equation models. For carotenoids, analyses were stratified by smoking status.

Results

None of the investigated nutrients except for carotenoids was significantly associated with changes in HbA_1c levels after 10 years. Regular intake of carotenoids from supplements and medications in amounts > 6.8mg/d (upper tertile) was associated with an absolute –0.26% (95% CI: –0.43 to –0.08) lower increase in HbA_1c levels compared with no intake of carotenoids. An inverse association was observed in those who never smoked but not in (former) smokers.

Conclusion

Larger prospective and intervention studies in non-diabetic/non-smoking individuals are needed to confirm the results and to assess whether the observed associations between carotenoid intake and change in HbA_1c levels are causal. If our results are confirmed, high carotenoid intake could be one strategy for the prevention of cardiovascular complications in non-diabetic people.

Elevation of HbA1C in Non-diabetic Hypothyroid Individuals: Is Anaemia the Connecting Link? -A Preliminary Study

AIM

Studies have shown elevated HbA1C in non-diabetic hypothyroid patients. Hypothyroid patients often show anaemia as an associated feature which is an another condition showing falsely elevated A1C. Hence this study is aimed to investigate whether elevated A1C in hypothyroidism can be attributed to anaemia.

MATERIAL AND METHODS

HbA1C levels of 120 non-diabetic hypothyroid patients (30 microcytic hypochromic anaemia, 30 normocytic normochromic anaemia and 60 non anemic patients) with 120 age, sex, plasma glucose levels and anaemia status matched controls were assessed. Anaemia status was determined by ferritin, Haemoglobin, red cell indices and peripheral smear. Glycemic status was determined by fasting Plasma glucose.

RESULTS

HbA1C levels in hypothyroid patients with hypochromic microcytic anaemia and normocytic normochromic anaemia were 6.82 ± 0.71% & 6.32 ± 0.75% against 6.43 ± 0.43% & 5.87 ± 0.46 % of euthyroid anaemia matched controls respectively. While hypothyroid non anemic patients showed A1C levels of 5.91 ± 0.31% against 5.46 ± 0.62% of euthyroid non anemic controls. Hypothyroid Patients with anaemia had a significant odds ratio 3.16 (95% CI 1.426-7.016) for HbA1C > 6.5.

DISCUSSION AND CONCLUSION

Non-diabetic hypothyroid individuals with anaemia shows elevate A1C levels in prediabetes range. Hence care should be excercised while using HbA1C as a diagnostic tool for diabetes in such patients.

Manjrekar P, P. Babu R, Hegde A, M.S. R. Influence of iron deficiency anemia on hemoglobin A1c levels in diabetic individuals with controlled plasma glucose levels

INTRODUCTION

Hemoglobin A1C (HbA1c) reflects patient's glycemic status over the previous 3 months. Previous studies have reported that iron deficiency may elevate A1C concentrations, independent of glycemia. This study is aimed to analyze the effect of iron deficiency anemia on HbA1c levels in diabetic population having plasma glucose levels in control.

METHODS

Totally, 120 diabetic, iron-deficient anemic individuals (70 females and 50 males) having controlled plasma glucose levels with same number of iron-sufficient non-anemic individuals were streamlined for the study. Their data of HbA1c (Bio-Rad D-10 HPLC analyzer), ferritin (cobas e411 ECLIA hormone analyzer), fasting plasma glucose (FPG, Roche Hitachi P800/917 chemistry analyzer), hemoglobin (Beckman Coulter LH780), peripheral smear examination, red cell indices, and medical history were recorded. Statistical analysis was carried out by student's t-test, Chi-square test, and Pearson's coefficient of regression.

RESULTS

We found elevated HbA1c (6.8 ± 1.4%) in iron-deficient individuals as compared to controls, and elevation was more in women (7.02 ± 1.58%). On further classification on the basis of FPG levels, A1C was elevated more in group having fasting glucose levels between 100-126 mg/dl (7.33 ± 1.55%) compared to the those with normal plasma glucose levels (<100 mg/dl). No significant correlation was found between HbA1c and ferritin and hemoglobin.

CONCLUSION

This study found a positive correlation between iron deficiency anemia and increased A1C levels, especially in the controlled diabetic women and individuals having FPG between 100-126 mg/dl. Hence, before altering the treatment regimen for diabetic patient, presence of iron deficiency anemia should be considered.

HbA1c and iron deficiency: a review

Conditions that affect erythrocyte turnover influence HbA1c concentrations and the International Expert Committee has warned clinicians to be aware of any conditions that could affect the turnover of red blood cells. Although many forms of anemia are associated with lowering of HbA1c, iron deficiency has been shown to shift HbA1c slightly upward. The exact mechanism through which iron deficiency anemia affects HbA1c levels, however still remains unclear. The explanations provided above are merely speculations, warranting further studies to confirm and elucidate the role of these factors. As little work has been done in this field so future and large scale studies are required which may address HbA1c enhancing effect and the mechanism of increased HbA glycation in iron deficiency properly.