HbA1c Test as a Tool in the Diagnosis of Gestational Diabetes Mellitus

Gestational diabetes mellitus prevalence in Brazil: a systematic review and meta-analysis

This study estimates gestational diabetes mellitus prevalence in Brazil. A systematic review was conducted with articles published between 2010 and 2021 on the PubMed, Scopus, Google Scholar, SciELO, LILACS and Virtual Health Library databases, as well as gray literature. Data were extracted using a standardized instrument together with the risk of bias assessment tool proposed by Hoy et al. A meta-analysis with robust variance and random effects was developed. Heterogeneity was verified using I2 and publication bias was assessed using funnel plot and Egger's test. Prevalence according to risk of bias, diagnostic criteria and country's regions was determined by subgroup analyses. A total of 32 studies were included, representing 21,942 women. gestational diabetes mellitus pooled prevalence was 14% (95%CI: 11.0; 16.0), considerably higher than estimates from previous studies. Regarding risk of bias, studies with low, medium, and high risk showed a pooled prevalence of 12%, 14% and 14%, respectively. Overall GRADE certainty of evidence rating was low. Most studies used the International Association of Diabetes in Pregnancy Study Group (IADPSG) criteria or the adapted IADPSG, showing a pooled prevalence of 15% and 14%, respectively. As for region, the pooled prevalence was higher in the Southeast (14%) and lower in the Central-West (9%). This is the first systematic review to provide evidence on gestational diabetes mellitus prevalence at a national level and to demonstrate considerable heterogeneity among articles and the influence of region, diagnostic criteria and study quality on the referred indicator.

A stepwise prediction and interpretation of gestational diabetes mellitus: Foster the practical application of machine learning in clinical decision

Background

Machine learning has shown to be an effective method for early prediction and intervention of Gestational diabetes mellitus (GDM), which greatly decreases GDM incidence, reduces maternal and infant complications and improves the prognosis. However, there is still much room for improvement in data quality, feature dimension, and accuracy. The contributions and mechanism explanations of clinical data at different pregnancy stages to the prediction accuracy are still lacking. More importantly, current models still face notable obstacles in practical applications due to the complex and diverse input features and difficulties in redeployment. As a result, a simple, practical but accurate enough model is urgently needed.

Design and methods

In this study, 2309 samples from two public hospitals in Shenzhen, China were collected for analysis. Different algorithms were systematically compared to build a robust and stepwise prediction system (level A to C) based on advanced machine learning, and models under different levels were interpreted.

Results

XGBoost reported the best performance with ACC of 0.922, 0.859 and 0.850, AUC of 0.974, 0.924 and 0.913 for the selected level A to C models in the test set, respectively. Tree-based feature importance and SHAP method successfully identified the commonly recognized risk factors, while indicated new inconsistent impact trends for GDM in different stages of pregnancy.

Conclusion

A stepwise prediction system was successfully established. A practical tool that enables a quick prediction of GDM was released at https://github.com/ifyoungnet/MedGDM.This study is expected to provide a more detailed profiling of GDM risk and lay the foundation for the application of the model in practice.

Comparing the screening methods for gestational diabetes mellitus before and during the COVID-19 pandemic: A systematic review

BACKGROUND

The oral glucose tolerance test (OGTT) is the gold standard for detecting gestational diabetes mellitus (GDM). However, during the COVID-19 pandemic, screening practices were reevaluated due to the risk of infection associated with the prolonged hospital visit required for the OGTT. Some countries have published novel screening protocols for GDM, suggesting the utilization of hemoglobin A1c (HbA1c), random plasma glucose (RPG), or fasting plasma glucose (FPG) in favor of OGTTs during the pandemic. Therefore, differences in screening methods before and after the epidemic need to be examined.

METHODS

A systematic search was carried out across five electronic databases (Cinahl, Medline, Embase, Pubmed, and Web of Science) between 2016 and 2023. The Critical Appraisal Skills Programme (CASP) checklist for cohort studies was used to evaluate the quality of included papers.

RESULTS

A total of 13 eligible studies were included. Prior to the COVID-19 pandemic, the OGTT was the recommended measure to screen GDM, internationally based on various official guidelines. During the pandemic, it was recommended that HbA1c or FPG, or RPG be used as a substitute for OGTTs. However, the new methods have low sensitivity, may not reflect accurately the prevalence of GDM, and may lead to many false-negative results in women and to adverse pregnancy and neonatal outcomes.

CONCLUSION

The new screening methods for GDM have poor accuracy and a high risk of adverse pregnancy outcomes. Comparatively, targeted screening tests to detect GDM according to the risk level are more effective in an emergency. In the future, the alternatives to OGTTs still need to be further explored in more depth.

Assessment of potential risk factors associated with gestational diabetes mellitus: evidence from a Mendelian randomization study

Background

Previous research on the association between risk factors and gestational diabetes mellitus (GDM) primarily comprises observational studies with inconclusive results. The objective of this study is to investigate the causal relationship between 108 traits and GDM by employing a two-sample Mendelian randomization (MR) analysis to identify potential risk factors of GDM.

Methods

We conducted MR analyses to explore the relationships between traits and GDM. The genome-wide association studies (GWAS) for traits were primarily based on data from the UK Biobank (UKBB), while the GWAS for GDM utilized data from FinnGen. We employed a false discovery rate (FDR) of 5% to account for multiple comparisons.

Results

The inverse-variance weighted (IVW) method indicated that the genetically predicted 24 risk factors were significantly associated with GDM, such as "Forced expiratory volume in 1-second (FEV1)" (OR=0.76; 95% CI: 0.63, 0.92), "Forced vital capacity (FVC)" (OR=0.74; 95% CI: 0.64, 0.87), "Usual walking pace" (OR=0.19; 95% CI: 0.09, 0.39), "Sex hormone-binding globulin (SHBG)" (OR=0.86; 95% CI: 0.78, 0.94). The sensitivity analyses with MR-Egger and weighted median methods indicated consistent results for most of the trats.

Conclusion

Our study has uncovered a significant causal relationship between 24 risk factors and GDM. These results offer a new theoretical foundation for preventing or mitigating the risks associated with GDM.

Performance of glycated hemoglobin A1c for the diagnosis of gestational diabetes mellitus during the SARS-CoV-2 pandemic in Belgium (2020-2021)

OBJECTIVES

During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, health care access was restricted. To reduce the risk of maternal SARS-CoV-2 infection, simplified screening recommendations for gestational diabetes mellitus (GDM) have been suggested, leading to glycated hemoglobin A1c (HbA1c) being proposed as an alternative to the oral glucose tolerance test (OGTT). This study aimed to assess the optimal HbA1c cutoff to confirm GDM diagnosis according to IADPSG/WHO2013 guidelines.

METHODS

In this retrospective study, 3361 pregnancies were followed at the hospital of Mouscron and the Cliniques Universitaires St Luc in Brussels (2020-2021). GDM was universally screened in the third trimester of gestation. The ROC curve was used to evaluate the diagnostic performance of HbA1c with OGTT as the reference. Sensitivity, specificity and likelihood ratios for different HbA1c thresholds were calculated.

RESULTS

In total, 312 women were selected due to HbA1c analysis in addition to OGTT, and 149 had GDM. The area under the ROC curve for GDM detection by HbA1c was 0.73 (95% CI 0.68-0.79, p < 0.0001). The cutoff value chosen as a possible threshold was HbA1c 5.5% (37 mmol/mol). The sensitivity, specificity, positive and negative likelihood ratios for this cutoff were 12.0%, 99.4%, 20 and 0.88, respectively. The Fagan nomogram test showed a posttest GDM probability of approximately 70%, corresponding to a 10-fold higher pretest probability. An HbA1c ≥ 5.5% (37 mmol/mol) would have avoided OGTT in 18% of women with GDM. These women with an HbA1c ≥ 5.5% had significantly higher rates of family history of diabetes, older age, higher BMI and higher blood glucose levels (fasting, 1 h and 2 h) at OGTT.

CONCLUSION

Our results are consistent with the literature concerning the diagnostic ability of GDM through HbA1c ≥ 5.5%.

Association between body mass index in the first half of pregnancy and gestational diabetes: A systematic review

Gestational diabetes mellitus is a more common complication in pregnancy and rising worldwide and screening for treating gestational diabetes mellitus is an opportunity for preventing its complications. Abnormal body mass index is the cause of many complications in pregnancy that is one of the major and modifiable risk factors in pregnancy too. This systematic review aimed to define the association between body mass index in the first half of pregnancy (before 20 weeks of gestation) and gestational diabetes mellitus. Web of Science, PubMed/Medline, Embase, Scopus, ProQuest, Cochrane library, and Google Scholar databases were systematically explored for articles published until April 31, 2022. Participation, exposure, comparators, outcomes, study design criteria include pregnant women (P), body mass index (E), healthy pregnant women (C), gestational diabetes mellitus (O), and study design (cohort, case–control, and cross-sectional). Newcastle–Ottawa scale checklists were used to report the quality of the studies. Eighteen quality studies were analyzed. A total of 41,017 pregnant women were in the gestational diabetes mellitus group and 285,351 pregnant women in the normal glucose tolerance group. Studies have reported an association between increased body mass index and gestational diabetes mellitus. Women who had a higher body mass index in the first half of pregnancy were at higher risk for gestational diabetes mellitus. In the first half of pregnancy, body mass index can be used as a reliable and available risk factor to assess gestational diabetes mellitus, especially in some situations where the pre-pregnancy body mass index is not available.

Glycated albumin in pregnancy: LC-MS/MS-based reference interval in healthy, nulliparous Scandinavian women and its diagnostic accuracy in gestational diabetes mellitus

Glycated albumin (GA) may be a useful biomarker of glycemia in pregnancy. The aim of this study was to establish the reference interval (RI) for GA, analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS), in healthy, nulliparous pregnant women. In addition, we assessed the accuracy of GA and glycated hemoglobin A1c (HbA1c) in the diagnosis of gestational diabetes mellitus (GDM). Finally, we explored the prevalence of GDM in healthy nulliparas, comparing three diagnostic guidelines (WHO-1999, WHO-2013 and the Norwegian guideline). The study was carried out at Stavanger University Hospital, Norway, and included a study population of 147 pregnant nulliparous women. An oral glucose tolerance test (OGTT) was performed and used as the gold standard for GDM diagnosis. Blood samples for analysis of GA and HbA1c were collected at pregnancy week 24-28. A nonparametric approach was chosen for RI calculation, and receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of GA and HbA1c. The established RI for GA in 121 pregnant women was 7.1-11.6%. The area under the ROC curves (AUCs) were 0.531 (GA) and 0.627 (HbA1c). According to the WHO-1999, WHO-2013 and the Norwegian guideline, respectively, 24 (16%), 36 (24%) and 21 (14%) women were diagnosed with GDM. Only nine women (6%) fulfilled the GDM-criteria of all guidelines. In conclusion, we established the first LC-MS/MS-based RI for GA in pregnant women. At pregnancy weeks 24-28, neither GA nor HbA1c discriminated between those with and without GDM. Different women were diagnosed with GDM using the three guidelines.

The role of first-trimester HbA1c in the early detection of gestational diabetes

Background

We aimed to assess the utility of HbA1c in the early detection of gestational diabetes (GDM) in the first trimester.

Methods

This prospective study was performed on 700 pregnant women in the perinatology clinic at a tertiary university hospital from March 2018 to March 2020. For all pregnant women, HbA1c and fasting blood glucose (FBG) levels were examined during the first trimester. Then, a GDM screening test was done within 24–28 weeks of pregnancy using a 100 g oral glucose tolerance test (OGTT) as the gold standard test. The GDM diagnosis was made according to the American Diabetes Association (ADA) criteria. Sensitivity, specificity, positive (PPV), and negative predictive value (NPV) of HbA1c and FBG were calculated using the receiver operating characteristic (ROC) curve.

Results

Of 700 participants, one hundred and fifteen (16.4%) women had GDM. The GDM patients were significantly older and had a higher pre-gestational body mass index and pregnancy weight gain compared to the non-GDM participants. The sensitivity and specificity for ruling out GDM at an HbA1c cut-off value of 4.85% was 92.2 and 32.8%, respectively, with a 95.5% NPV and a 21.2% PPV. Furthermore, sensitivity and specificity for diagnosing GDM at an HbA1c cut-off value of 5.45% was 54.8 and 96.8%, respectively, with a 91.5% NPV and a 76.8% PPV. Using HbA1c could decline OGTT in 40.4% of the pregnant women (28.7% with HbA1c < 4.85 and 11.7% with HbA1c ≥ 5.45%).

Conclusion

It seems that the first-trimester HbA1c cannot replace OGTT for the diagnosis of GDM because of its insufficient sensitivity and specificity. However, women with higher first-trimester HbA1c had a high risk for GDM incidence.

Monitoring gestational diabetes at the point-of-care via dual glycated albumin lateral flow assays in conjunction with a handheld reader

A dual assay cartridge was developed and used in conjunction with a handheld reader for sensing % glycated albumin to monitor gestational diabetes at home.

The diagnostic indicators of gestational diabetes mellitus from second trimester to birth: a systematic review

BACKGROUND

Gestational diabetes mellitus (GDM) is glucose intolerance first recognised during pregnancy. Both modalities and thresholds of the GDM diagnostic test, the Oral Glucose Tolerance Test (OGTT), have varied widely over time and among countries. Additionally, OGTT limitations include inconsistency, poor patient tolerability, and questionable diagnostic reliability. Many biological parameters have been reported to be modified by GDM and could potentially be used as diagnostic indicators. This study aimed to 1) systematically explore biomarkers reported in the literature as differentiating GDM from healthy pregnancies 2) screen those indicators assessed against OGTT to propose OGTT alternatives.

MAIN BODY

A systematic review of GDM diagnostic indicators was performed according to PRISMA guidelines (PROSPERO registration CRD42020145499). Inclusion criteria were full-text, comprehensible English-language articles published January 2009-January 2021, where a biomarker (from blood, ultrasound, amniotic fluid, placenta) was compared between GDM and normal glucose tolerance (NGT) women from the second trimester onward to immediately postpartum. GDM diagnostic method had to be clearly specified, and the number of patients per study higher than 30 in total or 15 per group. Results were synthesised by biomarkers.

RESULTS

Of 13,133 studies identified in initial screening, 174 studies (135,801 participants) were included. One hundred and twenty-nine studies described blood analytes, one amniotic fluid analytes, 27 ultrasound features, 17 post-natal features. Among the biomarkers evaluated in exploratory studies, Adiponectin, AFABP, Betatrophin, CRP, Cystatin-C, Delta-Neutrophil Index, GGT, TNF-A were those demonstrating statistically and clinically significant differences in substantial cohorts of patients (> 500). Regarding biomarkers assessed versus OGTT (i.e. potential OGTT alternatives) most promising were Leptin > 48.5 ng/ml, Ficolin3/adiponectin ratio ≥ 1.06, Chemerin/FABP > 0.71, and Ultrasound Gestational Diabetes Score > 4. These all demonstrated sensitivity and specificity > 80% in adequate sample sizes (> / = 100).

CONCLUSIONS

Numerous biomarkers may differentiate GDM from normoglycaemic pregnancy. Given the limitations of the OGTT and the lack of a gold standard for GDM diagnosis, advanced phase studies are needed to triangulate the most promising biomarkers. Further studies are also recommended to assess the sensitivity and specificity of promising biomarkers not yet assessed against OGTT.

TRIAL REGISTRATION

PROSPERO registration number CRD42020145499.

Early Gestational Diabetes Mellitus: Diagnostic Strategies and Clinical Implications

Preexisting diabetes mellitus (DM) should be ruled out early in pregnancy in those at risk. During screening, a significant proportion of women do not reach the threshold for overt DM but fulfill the criteria used for diagnosing conventional gestational DM (cGDM). There is no consensus on the management of pregnancies with intermediate levels of hyperglycemia thus diagnosed. We have used the term early gestational DM (eGDM) for this condition and reviewed the currently available literature. Fasting plasma glucose (FPG), oral glucose tolerance test, and glycated hemoglobin (HbA1c) are the commonly employed screening tools in early pregnancy. Observational studies suggest that early pregnancy FPG and Hba1c correlate with the risk of cGDM and adverse perinatal outcomes. However, specific cut-offs, including those proposed by the International Association of the Diabetes and Pregnancy Study Group, do not reliably predict the development of cGDM. Emerging data, though indicate that FPG ≥ 92 mg/dL (5.1 mmol/L), even in the absence of cGDM, signals the risk for perinatal complication. Elevated HbA1c, especially a level ≥ 5.9%, also correlates with the risk of cGDM and worsened outcome. HbA1c as a diagnostic test is however besieged with the usual caveats that occur in pregnancy. The studies that explored the effects of intervention present conflicting results, including a possibility of fetal malnutrition and small-for-date baby in the early treatment group. Diagnostic thresholds and glycemic targets in eGDM may differ, and large multicenter randomized controlled trials are necessary to define the appropriate strategy.

An Update on Screening Strategies for Gestational Diabetes Mellitus: A Narrative Review

Gestational diabetes mellitus (GDM) is a frequent medical complication during pregnancy. Screening and diagnostic practices for GDM are inconsistent across the world. This narrative review includes data from 87 observational studies and randomized controlled trials (RCTs), and aims to give an overview of the current evidence on screening strategies and diagnostic criteria for GDM. Screening in early pregnancy remains controversial and studies show conflicting results on the benefit of screening and treatment of GDM in early pregnancy. Implementing the one-step "International Association of Diabetes and Pregnancy Study Groups" (IADPSG) screening strategy at 24-28 weeks often leads to a substantial increase in the prevalence of GDM, without conclusive evidence regarding the benefits on pregnancy outcomes compared to a two-step screening strategy with a glucose challenge test (GCT). In addition, RCTs are needed to investigate the impact of treatment of GDM diagnosed with IADPSG criteria on long-term maternal and childhood outcomes. Selective screening using a risk-factor-based approach could be helpful in simplifying the screening algorithm but carries the risk of missing significant proportions of GDM cases. A two-step screening method with a 50g GCT and subsequently a 75g oral glucose tolerance test (OGTT) with IADPSG could be an alternative to reduce the need for an OGTT. However, to have an acceptable sensitivity to screen for GDM with the IADPSG criteria, the threshold of the GCT should be lowered from 7.8 to 7.2 mmol/L. A pragmatic approach to screen for GDM can be implemented during the COVID-19 pandemic, using fasting plasma glucose (FPG), HbA1c or even random plasma glucose (RPG) to reduce the number of OGTTs needed. However, usual guidelines and care should be resumed as soon as the COVID pandemic is controlled.

Effectiveness of Glycated Haemoglobin in the Diagnosis of Gestational Diabetes Mellitus among Pregnant Women in Port Harcourt, Nigeria

Background

Gestational Diabetes Mellitus (GDM) is a common metabolic complication in pregnancy with a broad range of adverse foetal and maternal outcomes if not properly managed. Due to the difficult nature of the Oral glucose tolerance test (OGTT), the utilization of the Glycatedhaemoglobin (HbA1c) test as a simpler and acceptable alternative has been suggested. The aims were to determine the GDM prevalence, the diagnostic accuracy, the optimal cut-off point and the validity of the HbA1c in diagnosing GDM using OGTT as the gold standard in the University of Port Harcourt Teaching Hospital (UPTH).

Methodology

This was a prospective cross-sectional study involving a cohort of 250 antenatal attendees at 24-28 weeks of pregnancy in the UPTH from 1st February 2018 - 30th April 2018. Socio-demographic data and results of the OGTT and HbA1c tests were analysed using SPSS 21.0 for windows® statistical software. The area under the Receiver Operating Characteristics (ROC) curve was used to determine the diagnostic accuracy of HbA1c. The Youden index was used to get the optimal cut-off point for HbA1c. The validity of the HbA1c was determined using sensitivity, specificity, positive predictive value and negative predictive value. The P-value at p<0.05 was set as the level of significance.

Results

Out of the 250 women, 36 (14.4%) had GDM hence in this study, the GDM prevalence was 14.4%. Area under the curve (AUC) = 0.649; 95% confidence interval: 0.550 - 0.748; p-value = 0.004. The optimal cut-off point for HbA1c was 5.18% with a sensitivity of 63.9%, a specificity of 59.3%, a positive predictive value of 20.9% and a negative predictive value of 90.7%.

Conclusion

The HbA1c at the Optimal cut-off point of 5.18% in our environment cannot replace the OGTT in the diagnosis of GDM because of its low sensitivity and specificity but will be useful in the screening for GDM because of its high negative predictive value at 24-28 weeks gestation. This will reduce the count of gravidae who undergo the cumbersome OGTT.

Is there a role for glycated albumin in the diagnosis of gestational diabetes mellitus?

BACKGROUND

Studies in the general population have advocated glycated albumin (GA) as a useful alternative to glycated haemoglobin (HbA1c) under conditions wherein the latter does not reflect glycaemic status accurately. There are few studies in other populations, especially in pregnant women. Therefore, the aim of this study was to assess the clinical utility of GA in the diagnosis of gestational diabetes mellitus (GDM).

MATERIALS AND METHODS

This diagnostic test accuracy study was performed in 149 Brazilian women at 24-28 weeks of gestation referred for an oral glucose tolerance test (OGTT) in a tertiary university hospital. Receiver Operating Characteristic (ROC) curves were used to access the performance of GA and HbA1c in the diagnosis of GDM by the reference OGTT.

RESULTS

GDM by OGTT (IADPSG criteria) was detected in 18.8% of participants. According to ROC analysis, the area under the curve (AUC) for GA was 0.531 (95% CI: 0.405-0.658, p = 0.065) lower than that for HbA1c [0.743 (95% CI: 0.636-0.849; p ≤ 0.001] for the detection of GDM (p = 0.004). The equilibrium cut-off value for GA was 12.6%; sensitivity and specificity in this cut-off point were 53.6% and 54.2%, respectively.

CONCLUSIONS

GA at 24-28 weeks of gestation does not have ability to correctly discriminate those with and without GDM. In summary, the lack of sensitivity found in our results do not support the solely use of GA in the diagnosis of GDM.

Comparison of Pregnancy Outcomes Using Different Gestational Diabetes Diagnostic Criteria and Treatment Thresholds in Multiethnic Communities between Two Tertiary Centres in Australian and New Zealand: Do They Make a Difference?

Introduction: Australia, but not New Zealand (NZ), has adopted the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria to diagnose gestational diabetes (GDM). We compared pregnancy outcomes using these different diagnostic approaches. Method: Prospective data of women with GDM were collected from one NZ (NZ) and one Australian (Aus) hospital between 2007–2018. Aus screening criteria with 2-step risk-based 50 g Glucose Challenge Testing (GCT) followed by 75 g-oral glucose tolerance testing (OGTT): fasting ≥ 5.5, 2-h ≥ 8.0 mmol/L (ADIPS98) changed to a universal OGTT and fasting ≥5.1, 1-h ≥ 10, 2-h ≥ 8.5 mmol/L (IADPSG). NZ used GCT followed by OGTT with fasting ≥ 5.5, 2-h ≥ 9.0 mmol/L (NZSSD); in 2015 adopted a booking HbA1c (NZMOH). Primary outcome was a composite of macrosomia, perinatal death, preterm delivery, neonatal hypoglycaemia, and phototherapy. An Aus subset positive using NZSSD was also defined. RESULTS: The composite outcome odds ratio compared to IADPSG (1788 pregnancies) was higher for NZMOH (934 pregnancies) 2.227 (95%CI: 1.84–2.68), NZSSD (1344 pregnancies) 2.19 (1.83–2.61), and ADIPS98 (3452 pregnancies) 1.91 (1.66–2.20). Composite outcomes were similar between the Aus subset and NZ. Conclusions: The IADPSG diagnostic criteria were associated with the lowest rate of composite outcomes. Earlier NZ screening with HbA1c was not associated with a change in adverse pregnancy outcomes.

Limiting the Use of Oral Glucose Tolerance Tests to Screen for Hyperglycemia in Pregnancy during Pandemics

We aimed to evaluate each proposal of Australian–New Zealand Societies to limit the number of oral glucose tolerance tests (OGTTs) to diagnose hyperglycemia in pregnancy (HIP) during the coronavirus disease 2019 (COVID-19) pandemic. At our university hospital (2012–2016), we retrospectively applied in 4245 women who had OGTT between 22 and 30 weeks of gestation (reference standard: WHO criteria) the proposals in which OGTT is performed only in high-risk women; in all (Option 1) or high-risk (Option 1-Sel) women with fasting plasma glucose (FPG) 4.7–5.0 mmol/L; in all (Option 2) or high-risk (Option 2-Sel) women without history of HIP and with FPG 4.7–5.0 mmol/L. We also tested FPG measurement alone in all high-risk women. Measuring FPG alone had a sensitivity of 49% (95% confidence interval 45–54) applying universal screening. Option 2 appeared to have the best balance considering the needed OGTT (17.3%), sensitivity (72% (67–76)) and rates of a composite outcome (true negative cases: 10.6%, false positive cases: 24.4%; true positive cases: 19.5%; false negative cases: 10.2%). Consideration of a history of HIP and measuring first FPG can avoid more than 80% of OGTTs and identify women with the highest risk of adverse HIP-related events.

Clinical practice recommendations for the detection and management of hyperglycemia in pregnancy from South Asia, Africa and Mexico during COVID-19 pandemic

The human coronavirus disease 2019 (COVID-19) pandemic has affected overall healthcare delivery, including prenatal, antenatal and postnatal care. Hyperglycemia in pregnancy (HIP) is the most common medical condition encountered during pregnancy. There is little guidance for primary care physicians for providing delivery of optimal perinatal care while minimizing the risk of COVID-19 infection in pregnant women. This review aims to describe pragmatic modifications in the screening, detection and management of HIP during the COVID- 19 pandemic. In this review, articles published up to June 2021 were searched on multiple databases, including PubMed, Medline, EMBASE and ScienceDirect. Direct online searches were conducted to identify national and international guidelines. Search criteria included terms to extract articles describing HIP with and/or without COVID-19 between 1^st March 2020 and 15^th June 2021. Fasting plasma glucose, glycosylated hemoglobin (HbA1c) and random plasma glucose could be alternative screening strategies for gestational diabetes mellitus screening (at 24–28 weeks of gestation), instead of the traditional 2 h oral glucose tolerance test. The use of telemedicine for the management of HIP is recommended. Hospital visits should be scheduled to coincide with obstetric and ultrasound visits. COVID-19 infected pregnant women with HIP need enhanced maternal and fetal vigilance, optimal diabetes care and psychological support in addition to supportive measures. This article presents pragmatic options and approaches for primary care physicians, diabetes care providers and obstetricians for GDM screening, diagnosis and management during the pandemic, to be used in conjunction with routine antenatal care.

Development of a fasting blood glucose-based strategy to diagnose women with gestational diabetes mellitus at increased risk of adverse outcomes in a COVID-19 environment

OBJECTIVE

To evaluate the role of fasting blood glucose (FBG) to minimise the use of the oral glucose tolerance test in pregnancy (POGTT) for the diagnosis of gestational diabetes mellitus (GDM).

RESEARCH DESIGN AND METHODS

We analysed the POGTTs of 26,242 pregnant women in Queensland, Australia, performed between 1 January 2015 and 30 June 2015. A receiver operator characteristics (ROC) assessment was undertaken to indicate the FBG level that most effectively identified women at low risk of an abnormal result.

RESULTS

There were 3,946 (15.0%) patients having GDM with 2,262 (8.6%) having FBG ≥ 5.1mmol/l. The ROC identified FBG levels >4.6mmol/l having the best specificity (77%) and sensitivity (54%) for elevated 1 and/or 2hr BGLs. There were 19,321 (73.7%) women having FBG < 4.7mmol/l with a prevalence of GDM of 4.0%, less than 1/3rd the overall rate. Only 4,638 (17.7%) women having FBGs from 4.7-5.0mmol/l would require further evaluation to confirm or exclude the diagnosis.

CONCLUSION

This contemporary study of women across the state of Queensland, Australia suggests the FBG can be used effectively to define glucose tolerance in pregnancy, minimising their contact with pathology laboratories and potential exposure to the corona virus. This analysis, used in conjunction with outcome data from the HAPO study, provides reassurance to women and their health professionals that FBG < 4.7mmol/l has both a low rate of abnormal glucose tolerance and minimal adverse pregnancy-associated complications.

Diagnostic accuracy of the triglyceride-glucose index for gestational diabetes screening: a practical approach

The oral glucose tolerance test (OGTT) remains as the gold standard to diagnose gestational diabetes mellitus (GDM); however, this test may be inconvenient and costly. Hence, other easy to perform and accurate diagnostic alternatives would be valuable for maternal care. The objective of the study was to assess the diagnostic performance of the TyG index to screen for GDM at 24-28 of pregnancy. A total of 140 pregnant women who received the one-step 2 h 75 g OGTT were included. Overall GDM prevalence was 27.1% according to IADSPG criteria. The mean TyG index value in the GDM group was significantly higher than the TyG index for the no GDM group (4.88 ± 0.70 versus 4.68 ± 0.19, p<.001). A sensitivity of 89% [95% CI 0.75-0.97] and a specificity of 50% [95% CI 0.39-0.60)], accompanied by a high negative predictive value of 93% was observed. No differences were found in maternal and neonatal outcomes irrespective of the TyG cutoff value for GDM. According to our results, the TyG index may be a highly sensitive and easy to perform screening test for GDM.

Accuracy of screening tests for gestational diabetes mellitus in Southeast Asia: A systematic review of diagnostic test accuracy studies

BACKGROUND

To investigate the accuracy of screening tests for gestational diabetes mellitus (GDM) in Southeast Asian pregnant women.

METHODS

We searched PubMed (MEDLINE), Web of Science, Cochrane Library, ClinicalTrials.gov, Google Scholar, and Google for relevant articles published in English up to November 2018 using search terms related to GDM, screening tests for GDM and diagnostic performance. The studies were independently screened and selected by both authors. The methodological quality of the included studies was independently assessed by quality assessment of diagnostic accuracy studies 2. A hierarchical summary receiver operating characteristic (HSROC) model was created to estimate the HSROC curve. The summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated in a meta-analysis using bivariate random-effects model.

RESULTS

A total of 19 studies were included in which the 100 g oral glucose tolerance test (OGTT) and 75 g OGTT were the two common reference standards for diagnosis of GDM. Most points of diagnostic performance in the HSROC 50 g GCT curve compared with the 100 g OGTT reference standard were clustered in the upper left-hand quadrant. The pooled sensitivity and specificity of the 50 g GCT were 79% (95% confidence interval [CI] 64%-89%) and 74% (95% CI 59%-85%), respectively. For the 75 g OGTT reference standard, the non-fasting 2-hour plasma glucose showed quite similar sensitivity the 50 g GCT compared with the 100 g OGTT reference standard. The pooled sensitivities and specificities of the fasting plasma glucose and hemoglobin A1c were 81% (95% CI 76%-86%) and 70% (95% CI 67%-72%), and 80% (95% CI 66%-90%) and 69% (95% CI 58%-78%), respectively.

CONCLUSION

Our findings indicate that the 50 g GCT using the threshold of 140 mg/dL is a good screening test for identifying GDM at 24 to 28 weeks' gestational age for both high-risk and universal screening strategies in Southeast Asian countries. The non-fasting 2-hour PG, fasting plasma glucose or hemoglobin A1c are alternative choices for screening.

The diagnostic accuracy of HbA1c in detecting gestational diabetes mellitus among Chinese pregnant individuals

Background

This study aims to investigate the diagnostic value of the glycated hemoglobin (HbA1c) test for detecting gestational diabetes mellitus (GDM) in pregnant Chinese patients.

Methods

We enrolled a large cohort of 19,261 pregnant individuals who had both oral glucose tolerance test (OGTT) and HbA1c test between 24 and 28 weeks of gestation in a large Chinese tertiary hospital consecutively from 2013 to 2018. We used Pearson's correlation test to evaluate the correlation between OGTT and HbA1c. The diagnostic accuracy of HbA1c for GDM was examined with the receiver operating characteristic curve, using OGTT as the reference standard.

Results

A total of 3,547 (18.42%) women were diagnosed with GDM. HbA1c was positively, but only weakly correlated with the fasting, 1-hour glucose, and 2-hour glucose (r=0.31, 0.24, and 0.25, respectively, all P<0.001). The area under the curve of the HbA1c level for detecting GDM was 0.664 (95% CI: 0.653-0.674, P<0.01). The optimal cut-off point of HbA1c for GDM diagnosis was determined at 5.0% (31 mmol/mol), which yielded a sensitivity of 60.1%, a specificity of 65.3%, a positive predictive value of 28.1%, and a negative predictive value of 87.9%.

Conclusions

HbA1c test is weakly correlated with OGTT during pregnancy, and it offers only limited value in diagnosing GDM among Chinese pregnant individuals.

The accuracy of haemoglobin A1c as a screening and diagnostic test for gestational diabetes: a systematic review and meta-analysis of test accuracy studies

PURPOSE OF REVIEW

Gestational diabetes mellitus (GDM) is associated with adverse pregnancy complications. Accurate screening and diagnosis of gestational diabetes are critical to treatment, and in a pandemic scenario like coronavirus disease 2019 needing a simple test that minimises prolonged hospital stay. We undertook a meta-analysis on the screening and diagnostic accuracy of the haemoglobin A1c (HbA1c) test in women with and without risk factors for gestational diabetes.

RECENT FINDINGS

Unlike the oral glucose tolerance test, the HbA1c test is simple, quick and more acceptable. There is a growing body of evidence on the accuracy of HbA1c as a screening and diagnostic test for GDM. We searched Medline, Embase and Cochrane Library and selected relevant studies. Accuracy data for different thresholds within the final 23 included studies (16 921 women) were pooled using a multiple thresholds model. Summary accuracy indices were estimated by selecting an optimal threshold that optimises either sensitivity or specificity according to different scenarios.

SUMMARY

HbA1c is more useful as a specific test at a cut-off of 5.7% (39 mmol/mol) with a false positive rate of 10%, but should be supplemented by a more sensitive test to detect women with GDM.

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.

Reliability of glycosylated hemoglobin in the diagnosis of gestational diabetes mellitus

Background

Oral glucose tolerance test (OGTT) performed at 24‐28 weeks gestation is the current recommended method to the diagnosis of gestational diabetes mellitus (GDM). Many recent studies investigating HbA1c in detecting GDM yield different results. There are no published data on HbA1c in the diagnosis of GDM in Sub‐Saharan countries including Sudan.

Methods

A cross‐sectional study was carried out at the antenatal care of Saad Abuelela Maternity Hospital, Khartoum, Sudan during the period from February to November 2018 to assess the reliability of HbA1c in the diagnosis of GDM. GDM was diagnosed according to the International Association of Diabetes and Pregnancy Study Groups using a 75‐g oral glucose tolerance test.

Results

Three hundred and forty‐eight women were enrolled. The mean (SD) of the age, gravidity, and gestational age of the enrolled women were 27.8 (5.6) years, 2.36 (2.2) and 26.26 (2.43) weeks, respectively. Sixty‐eight women (19.5%) had GDM. A poor productively for HbA1c in diagnosis GDM was shown (AUC = 0.62, 95% CI = 0.55‐0.69). At HbA1c level of 4.150%, the sensitivity and specificity of the diagnosis for GDM were 76.51% and 37.85%, respectively. At HbA1c level of 5.850%, the sensitivity and specificity of the diagnosis for GDM were 13.24% and 91.43%, respectively. While there was no significant (Spearman) correlation between fasting blood glucose and HbA1c, there were significant correlations between HbA1c and OGTT 1 and 2 hours of OGTT.

Conclusion

In this study, HbA1c has a poor reliability, insufficient sensitivity or specificity for use to diagnose GDM.

Glycated haemoglobin in the first trimester: A predictor of gestational diabetes mellitus in pregnant Asian Indian women

AIM

To assess the efficacy of first trimester glycated hemoglobin (HbA1c-FT) in diagnosing or predicting gestational diabetes mellitus (GDM) in Asian Indian women.

METHODS

This retrospective cohort study involved 2275 women who underwent both HbA1c-FT estimation and GDM screening with a one-step 75 g oral glucose tolerance test. Receiver Operating Characteristic (ROC) curve statistics were applied to assess the discriminative ability of HbA1c-FT in GDM diagnosis. A multivariable logistic regression analysis after adjusting for plausible confounders was used to evaluate the independent effect of HbA1c-FT on GDM diagnosis.

RESULTS

The mean HbA1c-FT of GDM (n = 578) and non-GDM women (n = 1697) were 5.04 + 0.04% and 4.9 + 0.37%, respectively (p < 0.001). Compared to women with a HbA1c-FT < 5.2%, the adjusted odds ratio to develop GDM of women with an HbA1c-FT range of 5.2-5.5% and those >5.6% to develop GDM were 1.627 (p < 0.004) and 2.6 (p < 0.001), respectively. The area under the ROC curve to detect GDM was 0.606 (95% CI: 0.519-0.633 p < 0.001), but the sensitivity and specificity of the HbA1c-FT were not sufficient to diagnose, rule in or rule out GDM.

CONCLUSIONS

HbA1c-FT is an independent GDM predictor in Asian Indian women but lacks sufficient sensitivity or specificity for use as a diagnostic test.

Screening for Gestational Diabetes Mellitus by Measuring Glycated Hemoglobin Can Reduce the Use of the Glucose Challenge Test

Background

Physiological changes during pregnancy, such as dilutional anemia and a reduced half-life of red blood cells, have prevented the use of glycated Hb (HbA_1c) as a biomarker for gestational diabetes mellitus (GDM). Nevertheless, increasing evidence supports the use of HbA_1c in GDM diagnostic strategies.We studied HbA_1c as a biomarker of GDM and its possible use as a screening test to avoid the use of the glucose challenge test (GCT).

Methods

This case-control study involved 607 pregnant women between the 24th and 28th week of gestation. HbA_1c level was determined, and GDM was diagnosed according to the National Diabetes Data Group criteria. The area under the ROC curve (AUC) was determined; two low and two high cut-off points were established to rule out GDM and classify high-risk pregnant women, respectively. For each cut-off, sensitivity (S), specificity (SP), and total number and percentage of GCTs avoided were determined.

Results

The AUC for HbA_1c diagnostic performance was 0.68 (95% confidence interval 0.57–0.79). Using 4.6% HbA_1c (27 mmol/mol) as the lower cut-off (S=100%), 14% of participants could avoid the GCT. Using 5.5% HbA_1c (36 mmol/mol) as the upper cut-off (SP =94.5%), 6% of participants would be considered at high risk.

Conclusions

HbA_1c can be used as a screening test prior to the GCT, thereby reducing the need for the GCT among pregnant women at a low risk of GDM.

Epigenetic modification of the pentose phosphate pathway and the IGF-axis in women with gestational diabetes mellitus

Aim: Gestational diabetes mellitus (GDM) has been linked with adverse long-term health outcomes for the fetus and mother. These effects may be mediated by epigenetic modifications. Materials & methods: Genome-wide RNA sequencing was performed in placental tissue and maternal blood in six GDM and six non-GDM pregnancies. Promoter region DNA methylation was examined for selected genes and correlated with gene expression to examine an epigenetic modulator mechanism. Results: Reductions of mRNA expression and increases in promoter methylation were observed for G6PD in GDM women, and for genes encoding IGF-binding proteins in GDM-exposed placenta. Conclusion: GDM involves epigenetic attenuation of G6PD, which may lead to hyperglycemia and oxidative stress, and the IGF-axis, which may modulate fetal macrosomia.

A simple model to predict risk of gestational diabetes mellitus from 8 to 20 weeks of gestation in Chinese women

Background

Gestational diabetes mellitus (GDM) is associated with adverse perinatal outcomes. Screening for GDM and applying adequate interventions may reduce the risk of adverse outcomes. However, the diagnosis of GDM depends largely on tests performed in late second trimester. The aim of the present study was to bulid a simple model to predict GDM in early pregnancy in Chinese women using biochemical markers and machine learning algorithm.

Methods

Data on a total of 4771 pregnant women in early gestation were used to fit the GDM risk-prediction model. Predictive maternal factors were selected through Bayesian adaptive sampling. Selected maternal factors were incorporated into a multivariate Bayesian logistic regression using Markov Chain Monte Carlo simulation. The area under receiver operating characteristic curve (AUC) was used to assess discrimination.

Results

The prevalence of GDM was 12.8%. From 8th to 20th week of gestation fasting plasma glucose (FPG) levels decreased slightly and triglyceride (TG) levels increased slightly. These levels were correlated with those of other lipid metabolites. The risk of GDM could be predicted with maternal age, prepregnancy body mass index (BMI), FPG and TG with a predictive accuracy of 0.64 and an AUC of 0.766 (95% CI 0.731, 0.801).

Conclusions

This GDM prediction model is simple and potentially applicable in Chinese women. Further validation is necessary.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2374-8) contains supplementary material, which is available to authorized users.

Diagnostic accuracy of HbA1c in detecting gestational diabetes mellitus

Objective: To investigate the diagnostic value of glycated hemoglobin A1c (HbA1c) in detecting gestational diabetes mellitus (GDM).Methods: Pregnant women at gestational age 24 weeks or more, who had abnormal GDM screening test, were enrolled in this prospective study. A HbA1c assessment was performed at the same time of 3-h 100 g oral glucose tolerance test (OGTT). GDM was diagnosed according to the National Diabetes Data Group for a 3-h 100 g OGTT. Sensitivity and specificity of HbA1c were evaluated and pregnancy outcome were recorded in aspects of gestational age at delivery, preeclampsia, primary cesarean section rate, birth weight, fetal macrosomia, and neonatal intensive care unit admission.Results: One hundred fourteen women were enrolled. There were 35 women with GDM using NDDG criteria. The area under the curve of the receiver operating characteristic curve for HbA1c detection of GDM was 0.725 (95% confidence interval 0.621-0.829). Cut-off value of HbA1c was 5.8%. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 17.1, 100, 100, 73.2, and 74.6%, respectively. Pregnancy outcome in both groups in this study has no statistical significance.Conclusions: HbA1c values cannot replace OGTT for the diagnosis of GDM. However, HbA1c might be a useful tool to reduce the number of OGTT, associated costs and patient inconvenience.

Optimal first trimester HbA1c threshold to identify Singaporean women at risk of gestational diabetes mellitus and adverse pregnancy outcomes: A pilot study

This pilot study examined the use of early HbA1c in screening for gestational diabetes mellitus and adverse pregnancy outcomes in Singapore. One hundred and fifty-one pregnant women with a gestational age of under 14 weeks had an HbA1c test measured with their antenatal bloods prior to a second trimester oral glucose tolerance test. Patient characteristics and pregnancy outcome data were collected. Gestational diabetes mellitus prevalence was 11%. A receiver operating characteristic curve showed an HbA1c level of 5.2% (33 mmol/mol), had an 82% sensitivity, 72% specificity, 97% negative predictive value and 27% positive predictive value to predict gestational diabetes mellitus. Women with HbA1c of 5.2% (33 mmol/mol) or over 5.2% (33 mmol/mol) were older, had higher BMI and were less likely to be Chinese than those with HbA1c less than 5.2% (33 mmol/mol). There was no difference in pregnancy outcomes. Early HbA1c less than 5.2% (33 mmol/mol) may be useful to exclude low-risk Singaporean women from further testing, while those with HbA1c of 5.2% (33 mmol/mol) or greater would still need a oral glucose tolerance test between 24 and 28 weeks' gestation.

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.

Molecular Biomarkers for Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a growing public health problem worldwide. The condition is associated with perinatal complications and an increased risk for future metabolic disease in both mothers and their offspring. In recent years, molecular biomarkers received considerable interest as screening tools for GDM. The purpose of this review is to provide an overview of the current status of single-nucleotide polymorphisms (SNPs), DNA methylation, and microRNAs as biomarkers for GDM. PubMed, Scopus, and Web of Science were searched for articles published between January 1990 and August 2018. The search terms included “gestational diabetes mellitus”, “blood”, “single-nucleotide polymorphism (SNP)”, “DNA methylation”, and “microRNAs”, including corresponding synonyms and associated terms for each word. This review updates current knowledge of the candidacy of these molecular biomarkers for GDM with recommendations for future research avenues.

Likelihood ratios of quantitative laboratory results in medical diagnosis: The application of Bézier curves in ROC analysis

Receiver operating characteristic (ROC) analysis is widely used to describe the discriminatory power of a diagnostic test to differentiate between populations having or not having a specific disease, using a dichotomous threshold. In this way, positive and negative likelihood ratios (LR+ and LR-) can be calculated to be used in Bayes’ way of estimating disease probabilities. Similarly, LRs can be calculated for certain ranges of test results. However, since many diagnostic tests are of quantitative nature, it would be desirable to estimate LRs for each quantitative result. These LRs are equal to the slope of the tangent to the ROC curve at the corresponding point. Since the exact distribution of test results in diseased and non-diseased people is often not known, the calculation of such LRs for quantitative test results is not straightforward. Here, a simple distribution-independent method is described to reach this goal using Bézier curves that are defined by tangents to a curve. The use of such a method would help in standardizing quantitative test results, which are not always comparable between different test providers, by reporting them as LRs for a specific diagnosis, in addition to, or instead of, quantities such as mg/L or nmol/L, or even indices or units.

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.

Point-of-care diagnostics to improve maternal and neonatal health in low-resource settings

Each day, approximately 830 women and 7400 newborns die from complications during pregnancy and childbirth. Improving maternal and neonatal health will require bringing rapid diagnosis and treatment to the point of care in low-resource settings. However, to date there are few diagnostic tools available that can be used at the point of care to detect the leading causes of maternal and neonatal mortality in low-resource settings. Here we review both commercially available diagnostics and technologies that are currently in development to detect the leading causes of maternal and neonatal mortality, highlighting key gaps in development where innovative design could increase access to technology and enable rapid diagnosis at the bedside.

Associations of mid-pregnancy HbA1c with gestational diabetes and risk of adverse pregnancy outcomes in high-risk Taiwanese women

BACKGROUND

The objective of this study was to investigate the associations among the mid-pregnancy glycated hemoglobin A1c (HbA1c) level, gestational diabetes (GDM), and risk of adverse pregnancy outcomes in women without overt diabetes and with positive 50-g, 1-h glucose challenge test (GCT) results (140 mg/dL or greater).

METHODS

This prospective study enrolled 1,989 pregnant Taiwanese women. A two-step approach, including a 50-g, 1-h GCT and 100-g, 3-h oral glucose tolerance test (OGTT), was employed for the diagnosis of GDM at weeks 23-32. The mid-pregnancy HbA1c level was measured at the time the OGTT was performed. A receiver operating characteristic (ROC) curve was used to determine the relationship between the mid-pregnancy HbA1c level and GDM. Multiple logistic regression models were implemented to assess the relationships between the mid-pregnancy HbA1c level and adverse pregnancy outcomes.

RESULTS

An ROC curve demonstrated that the optimal mid-pregnancy HbA1c cut-off point to predict GDM, as diagnosed by the Carpenter-Coustan criteria using a two-step approach, was 5.7%. The area under the ROC curve of the mid-pregnancy HbA1c level for GDM was 0.70. Compared with the levels of 4.5-4.9%, higher mid-pregnancy HbA1c levels (5.0-5.4, 5.5-5.9, 6.0-6.4, 6.5-6.9, and >7.0%) were significantly associated with increased risks of gestational hypertension or preeclampsia, preterm delivery, admission to the neonatal intensive care unit, low birth weight, and macrosomia (the odds ratio [OR] ranges were 1.20-9.98, 1.31-5.16, 0.88-3.15, 0.89-4.10, and 2.22-27.86, respectively).

CONCLUSIONS

The mid-pregnancy HbA1c level was associated with various adverse pregnancy outcomes in high-risk Taiwanese women. However, it lacked adequate sensitivity and specificity to replace the two-step approach in the diagnosis of GDM. The current study comprised a single-center prospective study; thus, additional, randomized control design studies are required.

The Best Cut-Off Value for HbA1c as a Screening Tool in Iranian Women With Gestational Diabetes Mellitus

Objective: Gestational diabetes mellitus (GDM) is a prevalent disorder which increases maternal and fetal complications. The oral glucose tolerance test (OGTT) is a traditional, time -consuming and intensive test which is poorly tolerated by pregnant women. To date, increasing evidence considered HbA1c as a screening tool and reported various cut-off values in different populations. In alignment with existing literature, we determined for the first time, the optimal cut-off value for HbA1c in Iranian women with GDM. Materials and methods: This case-control study was conducted in Valie-Asr hospital between June 2015 and March 2016. A total of 200 pregnant women who were diagnosed with GDM were selected as study cases. For the control group, 200 healthy women were randomly selected. Fasting blood samples were taken for biochemical analysis, and OGTT was done in all participants. Demographic and anthropometric indexes were measured. Performance of the HbA1c test was analyzed by the Receiver Operating Characteristic (ROC) curve, and the sensitivity and specificity for different HbA1c cut-off points were calculated subsequently. Results: Analysis showed that the mean age (p < 0.001) and BMI (p < 0.001) were significantly higher in the GDM group compared to those in non-GDM pregnant women. GDM participants reported positive family- and previous history of GDM more than healthy pregnant women (p = 0.04 and p < 0.001, respectively). All the markers for Lipid profile were significantly different between the two groups (p = <0.001) except for total cholesterol. The rate of Caesarean section and neonate's Apgar score were not significantly different between the two groups. The best equilibrium between sensitivity (80%) and specificity (76%) for HbA1c was 5.05%. Conclusion: Our results suggest that pregnant women with HbA1c of ≥ 5.05% should proceed with an OGTT. Further investigations with larger sample size are needed to provide more robust evidence for the diagnostic and screening value of HbA1c in identifying pregnant women with GDM.

Elevated glycated hemoglobin predicts macrosomia among Asian Indian pregnant women (WINGS-9)

AIM

The aim of this study was to determine the optimal glycated hemoglobin (HbA1c) cut point for diagnosis of gestational diabetes mellitus (GDM) and to evaluate the usefulness of HbA1c as a prognostic indicator for adverse pregnancy outcomes.

METHODS

HbA1c estimations were carried out in 1459 pregnant women attending antenatal care centers in urban and rural Tamil Nadu in South India. An oral glucose tolerance test was carried out using 75 g anhydrous glucose, and GDM was diagnosed using the International Association of the Diabetes and Pregnancy Study Groups criteria.

RESULTS

GDM was diagnosed in 195 women. Receiver operating curves showed a HbA1c cut point of ≥ 5.0% (≥31 mmol/mol) have a sensitivity of 66.2% and specificity of 56.2% for identifying GDM (area under the curve 0.679, confidence interval [CI]: 0.655-0.703). Women with HbA1c ≥ 5.0% (≥31 mmol/mol) were significantly older and had higher body mass index, greater history of previous GDM, and a higher prevalence of macrosomia compared to women with HbA1c < 5.0% (<31 mmol/mol). The adjusted odds ratio for macrosomia in those with HbA1c ≥ 5.0% (≥31 mmol/mol) was 1.92 (CI: 1.24-2.97, P = 0.003). However, other pregnancy outcomes were not significantly different.

CONCLUSION

In Asian Indian pregnant women, a HbA1c of 5.0% (31 mmol/mol) or greater is associated with increased risk of macrosomia.

Hemoglobin A1c as screening for gestational diabetes mellitus in Nordic Caucasian women

BACKGROUND

Gestational diabetes mellitus (GDM) increases the risk for preeclampsia and macrosomia. GDM is conventionally diagnosed by an oral glucose tolerance test (OGTT). Hemoglobin A1c (HbA1c) is a marker for the average glucose level the last 2-3 months. We aimed to study if HbA1c alone or in combination with patient characteristics can be used to screen for GDM and reduce the number of OGTTs, and whether it could predict preeclampsia or birth weight.

METHODS

855 women from a previous study on the effect of exercise on GDM prevalence were eligible, whereof 677 were included. GDM was diagnosed by WHO 1999 criteria (GDM-WHO) and modified IADPSG criteria (GDM-IADPSG), at pregnancy weeks 18-22 and 32-36. HbA1c analyzed at pregnancy weeks 18-22 and 32-36, variables from patient history and clinical examination were considered for logistic regression models. The diagnostic accuracy was assessed by ROC curve analysis.

RESULTS

Accumulated GDM prevalence was 6.7 % by WHO and 7.2 % by modified IADPSG criteria. Nearly a third could potentially have avoided an OGTT by using HbA1c to exclude GDM-IADPSG with a sensitivity of 88 % at week 18-22 and 97 % at week 32-36. Further, 16 % could have avoided an OGTT with a sensitivity of 96 % using HbA1c at week 18-22 to exclude GDM-IADPSG throughout pregnancy. HbA1c was not accurate at diagnosing GDM-IADPSG, and it was inaccurate at screening for GDM-WHO at any time point. Adding other predictors did not increase the number of potentially avoidable OGTTs significantly. HbA1c was not significantly associated with preeclampsia or birth weight.

CONCLUSIONS

HbA1c could potentially reduce the number of OGTTs.

Biological diagnosis of diabetes mellitus

Diabetes mellitus is a common disease whose complications are severe. For decades, the diagnosis of diabetes and prediabetes was using only fasting glucose or glucose two hours during an oral glucose tolerance test. Recently, it is possible to use HbA1c. Each of these tests has advantages and limitations that must be well known by clinicians for better care for patients. So they could use one, two or three of this tests to reach to a proper diagnosis. The aim of this article is about the strong and weak points of these tests.