First trimester glycosylated hemoglobin as a predictor of gestational diabetes mellitus

Predelivery HbA1c levels and their relationship with adverse perinatal outcomes in women with normal 75-g OGTT

PURPOSE

To analyze the elevation of HbA1c before full-term delivery in single pregnancy with normal 75 g- Oral glucose tolerance test (OGTT) screening and its association with adverse perinatal outcomes.

METHODS

From January to December 2022, an observational prospective study was conducted in a Single centre in China. 365 single pregnant women with normal OGTT were included in the study. HbA1c was measured during OGTT and before full-term delivery, and perinatal outcomes were collected. Participants' pre-delivery HBA1c values were analyzed and perinatal outcomes were compared. Logistic regression analysis was used for independent risk factors associated with elevated pre-delivery HbA1c ≥ 6.0%. The predictive value and truncation value were analyzed by ROC curve.

RESULTS

15.89% (58/365) of the Participants had a pre-delivery HBA1C value ≥ 6.0%. The incidence of neonatal asphyxia (13.79%, vs. 3.45%, vs. 2.26%, P = 0.007) and amniotic fluid fecal staining (29.31%, vs. 12.64%, vs. 12.03%, P = 0.004) were significantly increased in this group. The independent risk factor associated with pre-delivery HBA1c ≥ 6.0% was the fasting blood glucose(FBG) value of OGTT (OR = 51.308, 95% CI 12.93-203.67, P < 0.01) and the HBA1c value measured during OGTT (OR = 3.608, 95% CI 1.432-9.151, P = 0.007). When FBG was < 4.18 mmol/L and HBA1c was < 5.51%, The accuracy of predicting the pre-delivery HBA1c < 6.0% was 98.2%.

CONCLUSIONS

15.89% of the single pregnancy with normal OGTT had HbA1c ≥ 6.0% before full-term delivery, and they had an increased incidence of neonatal asphyxia and amniotic fluid fecal staining. When the FBG ≥ 4.18 mmol/l or the HBA1c ≥ 5.51% during the OGTT screening, repeated OGTT were recommended in late pregnancy.

Association of Early Pregnancy Values of Glycosylated Hemoglobin and the Development of Gestational Diabetes Mellitus

Introduction There is no consensus regarding screening and diagnostic methods for gestational diabetes mellitus (GDM). The present study aimed to evaluate the association between early pregnancy values of glycosylated hemoglobin and the development of gestational diabetes mellitus among pregnant women in a tertiary care hospital in eastern India. Methods The prospective cohort study included 200 pregnant women aged between 18 and 35 years in their first trimester (gestational age eight to 13 weeks) attending the antenatal clinics of the study hospital. A glycated hemoglobin (HbA1c) test and a 75-g oral glucose tolerance test (OGTT) test were done in all study participants in their first trimester. Pregnant women with HbA1c ≥6.5% and OGTT ≥140 mg/dl were excluded from the study. In other women, the second trimester (24-28 weeks) and the third trimester OGTT (32-34 weeks) were done to detect gestational diabetes mellitus. Data collection was initiated after the approval of the Information, Education, and Communication (IEC) and relevant authorities. Receiver operating characteristic (ROC) analysis was done to identify the cut-off value of HbA1c that predicted the development of GDM. Results The incidence of GDM was 33% among our study participants. The mean HbA1c was significantly higher among women who had GDM (5.4 ± 0.4%) as compared to those who did not develop GDM (4.9 ± 0.2%) (p<0.001). On ROC analysis of HbA1c values to predict the development of GDM, a cut-off value of HbA1c ≥5.25%, irrespective of risk status, was calculated to have 84.8% sensitivity and 62.7% specificity, and among the high-risk group, HbA1c ≥5.15% had 83.3% sensitivity and 97% specificity in predicting GDM. On stratified analysis, a moderately strong positive correlation was demonstrated between HbA1c values and OGTT in the second trimester in both high-risk and low-risk cohorts (p<0.05). Conclusion Based on the findings of the present study, HbA1c can be proposed to be a suitable biomarker for GDM prediction, probably not independently but rather as a component of a multi-marker approach for high- and low-risk pregnant groups.

The Impact of Ethnicity on Fetal and Maternal Outcomes of Gestational Diabetes

Background and Objectives: The prevalence of gestational diabetes mellitus (GDM) significantly varies across different ethnic groups. In particular, Africans, Latinos, Asians and Pacific Islanders are the ethnic groups with the highest risk of GDM. The aim of this study was to evaluate the impact of ethnicity on pregnancy outcomes in GDM. Patients and Methods: n = 399 patients with GDM were enrolled, n = 76 patients of high-risk ethnicity (HR-GDM), and n = 323 of low-risk ethnicity (LR-GDM). Clinical and biochemical parameters were collected during pregnancy until delivery. Fetal and maternal short-term outcomes were evaluated. Results: HR-GDM had significantly higher values of glycosylated hemoglobin checked at 26−29 weeks of gestation (p < 0.001). Gestational age at delivery was significantly lower in HR-GDM (p = 0.03). The prevalence of impaired fetal growth was significantly higher in HR-GDM than LR-GDM (p = 0.009). In logistic regression analysis, the likelihood of impaired fetal growth was seven times higher in HR-GDM than in LR-GDM, after adjustment for pre-pregnancy BMI and gestational weight gain (OR = 7.1 [2.0−25.7] 95% CI, p = 0.003). Conclusions: HR-GDM had worse pregnancy outcomes compared with LR-GDM. An ethnicity-tailored clinical approach might be effective in reducing adverse outcomes in GDM.

Maternal metabolic factors and the association with gestational diabetes: A systematic review and meta-analysis

Gestational diabetes (GDM) is associated with several adverse outcomes for the mother and child. Higher levels of individual lipids are associated with risk of GDM and metabolic syndrome (MetS), a clustering of risk factors also increases risk for GDM. Metabolic factors can be modified by diet and lifestyle. This review comprehensively evaluates the association between MetS and its components, measured in early pregnancy, and risk for GDM. Databases (Cumulative Index to Nursing and Allied Health Literature, PubMed, Embase, and Cochrane Library) were searched from inception to 5 May 2021. Eligible studies included ≥1 metabolic factor (waist circumference, blood pressure, fasting plasma glucose (FPG), triglycerides, and high-density lipoprotein cholesterol), measured at <16 weeks' gestation. At least two authors independently screened potentially eligible studies. Heterogeneity was quantified using I² . Data were pooled by random-effects models and expressed as odds ratio and 95% confidence intervals (CIs). Of 7213 articles identified, 40 unique articles were included in meta-analysis. In analyses adjusting for maternal age and body mass index, GDM was increased with increasing FPG (odds ratios [OR] 1.92; 95% CI 1.39-2.64, k = 7 studies) or having MetS (OR 2.52; 1.65, 3.84, k = 3). Women with overweight (OR 2.17; 95% CI 1.89, 2.50, k = 12) or obesity (OR 4.34; 95% CI 2.79-6.74, k = 9) also were at increased risk for GDM. Early pregnancy assessment of glucose or the MetS, offers a potential opportunity to detect and treat individual risk factors as an approach towards GDM prevention; weight loss for pregnant women with overweight or obesity is not recommended. Systematic review registration: PROSPERO CRD42020199225.

Is HbA1c in the first trimester associated with adverse outcomes among pregnant Asian Indian women without gestational diabetes?

AIMS

The aim of this study is to determine the association of elevated HbA1c in the first trimester (HbA1c-FT) with adverse events among pregnant Asian Indian women without gestational diabetes (GDM).

METHODS

This retrospective cohort study included 1618 pregnant women who delivered at a single urban tertiary care center and had HbA1c-FT estimation between January 2011 and September 2017. Those with GDM according to a 75-g OGTT after 24 gestational weeks were excluded. Multivariable logistic regression models assessed the association between elevated HbA1c-FT and adverse events.

RESULTS

At a cutoff of ≥37 mmol/mol (5.5%), HbA1c-FT was associated with preterm birth at <37 gestational weeks (adjusted odds ratio (OR) 2.10, 95% CI 1.11-3.98). There was a continuum of risk for primary caesarean delivery with higher HbA1c-FT levels (adjusted OR per 5-mmol/mol (0.5%) increase in HbA1c-FT for primary caesarean delivery: 1.27, 95% CI 1.06-1.52). In the crude analysis, gestational hypertension was associated with HbA1c-FT, but not after adjustment for confounding factors. HbA1c-FT was not associated with other adverse events (macrosomia, large for gestational age babies, or other neonatal complications).

CONCLUSIONS

Even without GDM, the results suggest an association of HbA1c-FT with preterm birth and primary caesarian delivery among Asian Indian women.

The diagnostic value of glycosylated hemoglobin for gestational diabetes mellitus in Asian populations: A systematic review and meta-analysis

AIMS

To investigate the role of glycosylated hemoglobin in assisting the oral glucose tolerance test for gestational diabetes mellitus (GDM) diagnosis in Asian populations.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were searched from inception to December 2020. Review Manager was applied to assess the quality of studies and risk of bias. MetaDiSc was used to measure diagnostic odds ratio, sensitivity, specificity, positive and negative likelihood ratios, area under receiving operating characteristic curve, and heterogeneity.

RESULTS

A total of 19 original studies (32 669 women) were retrieved. The diagnostic efficiency of glycosylated hemoglobin was quantified from 4.5% to 6.0%. The pooled sensitivity (0.624, 0.609-0.638) and specificity and (0.624, 0.617-0.631) achieved optimal equilibrium at 5.0%. High sensitivity (0.911, 0.902-0.920) and low negative likelihood ratio (0.431, 0.365-0.508) at 4.6% as the rule-out cut-off, while with limited sensitivity, high specificity (0.990, 0.986-0.993) and positive likelihood ratio (8.309, 4.251-16.242) occurred at 5.8% as the rule-in cut-off. Heterogeneity was detected in parts of subgroup analyses (I²  > 50%). The diagnostic odds ratio and 95% confidence interval performance were better in the population with risk factors (6.314, 3.543-11.254) than those without (4.178, 2.332-7.488).

CONCLUSIONS

Glycosylated hemoglobin is a potential tool in assisting GDM diagnosis in Asian populations, which has a better applicability based on the rule-out and rule-in algorithm (4.6%-5.8%), particularly for pregnant women with risk factors.

A model for predicting gestational diabetes mellitus in early pregnancy: a prospective study in Thailand

Objective

To develop a predictive model using the risk factors of gestational diabetes mellitus (GDM) and construct a predictive nomogram for GDM risk in women during early pregnancy.

Methods

A prospective study was conducted in two tertiary hospitals among pregnant women with gestational age ≤14 weeks. Early GDM was diagnosed if an abnormal 100 g oral glucose tolerance test was detected using the Carpenter and Coustan criteria after an abnormal 50 g glucose challenge test. The factors included in the model were ACOG risk factors; maternal age; family history of hypertensive disorder in pregnancy; family history of dyslipidemia; gravida; parity; histories of preterm birth, early fetal death, abortion, stillbirth, and low birth weight; and glycated hemoglobin (HbA1c) levels. The predictive models for early GDM were analyzed using multiple logistic regression analyses. The nomograms were constructed, and their discrimination ability and predictive accuracy were tested.

Results

Of the 553 pregnant women, 54 (9.8%) were diagnosed with early GDM. In the integrated model, there was a history of GDM (adjusted odds ratio [aOR], 5.15; 95% confidence interval [CI], 1.82–14.63; P=0.004), HbA1c threshold ≥5.3% (aOR, 2.61; 95% CI, 1.44–4.74; P=0.002), and family history of dyslipidemia (aOR, 2.68; 95% CI, 1.37–5.21; P=0.005). The integrated nomogram model showed that a history of GDM had a high impact on the risk of early GDM. Its discrimination and mean absolute error were 0.76 and 0.009, respectively.

Conclusion

Application of the predictive model and nomogram will help healthcare providers investigate the probability of early GDM, especially in resource-limited countries.

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.

Prediabetes and pregnancy: Early pregnancy HbA1c identifies Australian Aboriginal women with high-risk of gestational diabetes mellitus and adverse perinatal outcomes

AIMS

To assess whether early pregnancy HbA_1c can predict gestational diabetes mellitus (GDM) and adverse birth outcomes in Australian women.

METHODS

Prospective study of 466 women without diabetes, aged ≥16-years at first antenatal presentation. Recruitment was from 27 primary healthcare sites in rural and remote Australia from 9-January 2015 to 31-May 2018. HbA_1c was measured with first antenatal investigations (<20-weeks gestation). Primary outcome measure was predictive value of HbA_1c for GDM, by routine 75 g oral glucose tolerance test (OGTT; ≥24-weeks gestation), and for large-for-gestational-age (LGA) newborn.

RESULTS

Of 396 (129 Aboriginal) women with routine OGTT, 28.8% had GDM (24.0% Aboriginal). HbA_1c ≥5.6% (≥38 mmol/mol) was highly predictive (71.4%, 95% CI; 47.8-88.7%) for GDM in Aboriginal women, and in the total cohort increased risk for LGA newborn (RR 2.04, 95% CI; 1.03-4.01, P = 0.040). There were clear differences between Aboriginal and non-Aboriginal women: 16.3% v 5.2% (P < 0.001) had elevated HbA_1c whereas 12.4% v 29.6% (P < 0.001) developed hyperglycemia during pregnancy.

CONCLUSIONS

Early pregnancy HbA_1c ≥5.6% (≥38 mmol/mol) identifies Aboriginal women with apparent prediabetes and elevated risk of having an LGA newborn. Universal HbA_1c at first antenatal presentation could facilitate earlier management of hyperglycemia and improved perinatal outcome in this high-risk population.

Universal HbA1c screening and gestational diabetes: a comparison with clinical risk factors

BACKGROUND

Screening strategies for gestational diabetes mellitus (GDM), particularly early GDM, have traditionally relied upon the use of clinical risk factors (CRFs). Although commonly used in nonpregnant patients, HbA1c screening is not widely used despite reports of abnormal HbA1c values being predictive of GDM development. The aims of this study are to assess the utility of universal HbA1c screening in predicting GDM and to compare universal screening to targeted CRF-based screening for the diagnosis of GDM.

STUDY DESIGN

This is a retrospective cohort study of patients undergoing universal HbA1c screening at ≤16 completed weeks gestation with a singleton pregnancy between December 2016 and April 2018 at a single urban tertiary care center. Patients with preexisting diabetes (HbA1c ≥6.5%) or patients who did not have glucose tolerance testing were excluded. Patients with HbA1c 5.7-6.4% underwent early two-step GDM screening. Positive screens were diagnosed with early GDM. Normal early screeners underwent repeat 3rd trimester screening. Clinical risk factors for early GDM screening at our institution prior to universal screening were history of GDM, body mass index (BMI) ≥40 kg/m², prior macrosomia (birth weight ≥4000 g) or stillbirth, and polycystic ovary syndrome. Multivariable regression was performed to assess the relationship between HbA1c and GDM. The predictive ability of universal HbA1c screening compared to that of CRFs was evaluated by testing for differences in the area under the curve (AUC) of receiver operating curves (ROCs).

RESULTS

One thousand nine hundred and fifteen patients met inclusion criteria. Two hundred and thirty-one (12.1%) patients had an elevated HbA1c ≥5.7%. Patients with elevated HbA1c were more likely to be older, Black, or obese compared with patients with normal HbA1c values. After adjusting for Black race, BMI, age, and public insurance, the odds of GDM development are 3.50 (95%CI 2.26-5.39) times higher among patients with HbA1c ≥5.7% compared to those with a normal HbA1c. Clinical risk factors for early glucose screening were present in 33% of patients with an elevated HbA1c. The AUC of CRF screening and HbA1c ≥5.7% was 0.72 and 0.75, respectively (p= .07), after controlling for Black race, BMI, maternal age, and insurance.

CONCLUSIONS

An elevated HbA1c is associated with an increased risk of GDM. Universal HbA1c screening performs as favorably as CRF based screening for the prediction of GDM.

Pregnancy outcomes in women with booking HbA1c ≤ 40 mmol/mol compared with 41-49 mmol/mol in South Auckland, New Zealand

AIMS

There are few data on pregnancy outcomes in women with pre-diabetes (HbA1c 41-49 mmol/mmol) at pregnancy booking. We aimed to (i) identify the proportion of women in Counties Manukau Health (CMH), South Auckland, New Zealand (NZ), with pre-diabetes at booking and (ii) compare outcomes between women with normal HbA1c and pre-diabetes.

MATERIALS AND METHODS

Using data from a multi-ethnic population of 10,869 singleton pregnancies, booked at <20 weeks from January 2017 to December 2018 in CMH, we compared outcomes between those with normal HbA1c (≤40 mmol/mol) and those with pre-diabetes (HbA1c 41-49 mmol/mol). The primary outcomes were gestational diabetes mellitus (GDM) by NZ criteria and large for gestational age (LGA) defined as birthweight >90th customised centile. Logistic regression determined the contribution of HbA1c 41-49 mmol/mol to the development of GDM.

RESULTS

Among 10,869 participants, 193 (1.78%) had an HbA1c 41-49 mmol/mol at <20 weeks' gestation. Those with HbA1c 41-49 mmol/mol were 11 times more likely to develop GDM (59.6 vs 7.9%; adjusted odds ratio (aOR) 11.16 (7.59, 16.41)) and were more likely to have an LGA baby (47 (24.4%) vs 1436 (13.5%) aOR 1.63 (1.10, 2.41)) versus those with normal HbA1c. They also had significantly higher rates of pre-eclampsia, caesarean sections, preterm births and perinatal deaths.

CONCLUSIONS

Nearly two-thirds of women with a booking HbA1c of 41-49 mmol/mmol developed GDM as well as multiple other perinatal complications compared to women with HbA1c ≤40. Trials to evaluate the impact of treatment in early pregnancy on the risk of late-pregnancy complications are required.

Pregnancy outcomes among women with class III obesity with normal early glucola

BACKGROUND

Because obese women are at increased risk for insulin resistance and development gestational diabetes (GDM), the American College of Obstetricians and Gynecologists (ACOG) recommends early GDM screening in this population. For obese women with a normal early 1-hour 50 g oral glucose challenge test (eGCT), the risk of developing GDM later in the pregnancy is unknown. Thus, we aimed to assess the risk of developing gestational diabetes based on the value of a normal eGCT.

STUDY DESIGN

Retrospective cohort of non-anomalous singleton pregnancies with maternal body mass index (BMI) ≥40 at the time of entry to prenatal care at a single institution from 2013 to 2017. Pregnancies with abnormal early 1-hour 50 g glucose challenge test (eGCT), multiple gestation, late entry to care, type 1 or 2 diabetes, and missing diabetes-screening information are excluded. Primary outcome was development of GDM. Secondary outcomes include fetal growth restriction, macrosomia, gestational age at delivery, large for gestational age, delivery BMI, total weight gain in pregnancy, induction of labor, shoulder dystocia, and cesarean delivery. Bivariate statistics compare demographics, pregnancy complications and delivery characteristics of women who had an eGCT≤ 100 mg/dL (low-normal eGCT) and women who had an eGCT of 101-134 mg/dL (high-normal eGCT). Regression models used to estimate odds of primary outcome.

RESULTS

Of 169 women, 66(39%) had a low-normal eGCT, and 103(61%) had a high-normal eGCT. Women in the low-normal eGCT group were more likely to use recreational drugs (p = 0.03), other baseline demographics did not differ. The rate of GDM was low in this population (5.3%), with no difference in the rate of GDM between with a low-normal eGCT (1.5%) and high-normal eGCT (7.7%) (p = 0.09). The median neonatal birthweight was higher in the high-normal GCT group (3405 g) as compared to the low-no GCT (3285 g) (p = 0.03).

CONCLUSIONS

Among women with class 3 obesity, the specific value of an early normal GCT was not associated with developing gestational diabetes mellitus later in the pregnancy. Larger studies are needed confirm these findings.

A Review on Research Progress in the Application of Glycosylated Hemoglobin and Glycated Albumin in the Screening and Monitoring of Gestational Diabetes

Glycosylated hemoglobin (HbA1C) and glycated albumin (GA) can be used for blood glucose management of a person with diabetes as a result of their convenience and stability. However, there is no corresponding standard for the application of glycosylated hemoglobin and glycosylated albumin in gestational diabetes mellitus (GDM). In this review, we summarize the published research and discuss three aspects of the significance of HBA1C and GA in GDM patients: screening of gestational diabetes mellitus, blood glucose monitoring and the relationship with pregnancy outcome. At present, studies suggest that HBA1C can be used as a screening indicator for pregnant women, but it cannot completely replace OGTT. HbA1C and GA can be used for blood glucose management in patients with GDM to reduce the incidence of GDM complications. However, the application of HBA1C and GA in GDM still needs more research and clinical practice support.

Metabolic profiling of pre-gestational and gestational diabetes mellitus identifies novel predictors of pre-term delivery

Background

Pregnant women with gestational diabetes mellitus (GDM) or type 2 diabetes mellitus (T2DM) are at increased risks of pre-term labor, hypertension and preeclampsia. In this study, metabolic profiling of blood samples collected from GDM, T2DM and control pregnant women was undertaken to identify potential diagnostic biomarkers in GDM/T2DM and compared to pregnancy outcome.

Methods

Sixty-seven pregnant women (21 controls, 32 GDM, 14 T2DM) in their second trimester underwent targeted metabolomics of plasma samples using tandem mass spectrometry with the Biocrates MxP^® Quant 500 Kit. Linear regression models were used to identify the metabolic signature of GDM and T2DM, followed by generalized linear model (GLMNET) and Receiver Operating Characteristic (ROC) analysis to determine best predictors of GDM, T2DM and pre-term labor.

Results

The gestational age at delivery was 2 weeks earlier in T2DM compared to GDM and controls and correlated negatively with maternal HbA1C and systolic blood pressure and positively with serum albumin. Linear regression models revealed elevated glutamate and branched chain amino acids in GDM + T2DM group compared to controls. Regression models also revealed association of lower levels of triacylglycerols and diacylglycerols containing oleic and linoleic fatty acids with pre-term delivery. A generalized linear model ROC analyses revealed that that glutamate is the best predictors of GDM compared to controls (area under curve; AUC = 0.81). The model also revealed that phosphatidylcholine diacyl C40:2, arachidonic acid, glycochenodeoxycholic acid, and phosphatidylcholine acyl-alkyl C34:3 are the best predictors of GDM + T2DM compared to controls (AUC = 0.90). The model also revealed that the triacylglycerols C17:2/36:4 and C18:1/34:1 are the best predictors of pre-term delivery (≤ 37 weeks) (AUC = 0.84).

Conclusions

This study highlights the metabolite alterations in women in their second trimester with diabetes mellitus and identifies predictive indicators of pre-term delivery. Future studies to confirm these associations in other cohorts and investigate their functional relevance and potential utilization for targeted therapies are warranted.

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.

Glycosylated Hemoglobin A1c Improves the Performance of the Nomogram for Predicting the 5-Year Incidence of Type 2 Diabetes

AIM

To develop and validate a model, which combines traditional risk factors and glycosylated hemoglobin A1c (HbA1c) for predicting the risk of type 2 diabetes (T2DM).

MATERIALS AND METHODS

This is a historical cohort study from a collected database, which included 8419 males and 7034 females without diabetes at baseline with a median follow-up of 5.8-years and 5.1-years, respectively. Multivariate cox regression analysis was used to select significant prognostic factors of T2DM. Two nomograms were constructed to predict the 5-year incidence of T2DM based on traditional risk factors (Model 1) and traditional risk factors plus HbA1c (Model 2). C-index, calibration curve, and time-dependent receiver-operating characteristic (ROC) curve were conducted in the training sets and validation sets.

RESULTS

In males, the C-index was 0.824 (95% CI: 0.795-0.853) in Model 1 and 0.867 (95% CI: 0.840-0.894) in Model 2; in females, the C-index was 0.830 (95% CI: 0.770-0.890) in Model 1 and 0.856 (95% CI: 0.795-0.917) in Model 2. The areas under curve (AUC) in Model 2 for prediction of T2DM development were higher than in Model 1 at each time point. The calibration curves showed excellent agreement between the predicted possibility and the actual observation in both models. The results of validation sets were similar to the results of training sets.

CONCLUSION

The proposed nomogram can be used to accurately predict the risk of T2DM. Compared with the traditional nomogram, HbA1c can improve the performance of nomograms for predicting the 5-year incidence of T2DM.

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.