Glucose tolerance test with a single abnormal value in pregnancy and the risk of type-2 diabetes mellitus

A framework to classify gestational diabetes diagnosed by routine antenatal 75g glucose tolerance testing

OBJECTIVE

To create an objective framework to classify gestational diabetes mellitus diagnosed by routine antenatal 75 g diabetes testing results to provide an alternative to current treatment-based classification.

METHODS

A framework was created to classify gestational diabetes according to the severity of glycemic abnormalities after routine antenatal 75 g GTT (classes 1 through 4, determined by fasting and post-test glycemic abnormalities). A retrospective cohort chart review was used to correlate clinically how often diet therapy alone maintained glycemic targets throughout pregnancy in each class. Chi-square analysis was used to assess inter-class differences in the success of diet therapy alone maintaining glycemic targets throughout pregnancy.

RESULTS

Seventy-four of 228 (33%), 35/228 (15%), 76/228 (33%), and 43/228 (19%) of the study population were classified as Class 1, 2, 3, or 4, respectively. Of eighty-nine patients who maintained glycemic targets throughout pregnancy with diet alone 51/89 (57%) were Class 1, 20/89 (22.5%) were Class 2, 11/89 (12.5%) were Class 3, and 7/89 (8%) were Class 4. Chi-square analysis showed statistically significant inter-class differences in the likelihood of diet therapy alone maintaining glycemic targets throughout pregnancy.

CONCLUSION

In this framework classifying gestational diabetes according to the severity of glycemic abnormalities after routine antenatal 75 g GTT (an objective proxy for disease severity), the higher the assigned class, the less likely that diet therapy alone maintained glycemic targets throughout pregnancy (a clinical proxy for disease severity).

One abnormal value in oral glucose tolerance test during pregnancy and type 2 diabetes risk: Insights from a 5-Year Follow-Up study

OBJECTIVES

To evaluate the risk of type 2 diabetes(T2D) following one abnormal value(OAbV) in an oral glucose tolerance test(oGTT) performed during pregnancy.

STUDY DESIGN

A retrospective analysis of parturients between 01.01.2017 and 31.12.2020 with 5 years of follow-up after delivery. Glucose levels during pregnancy were extracted from the computerized laboratory system of Meuhedet HMO and cross-tabulated with the Israeli National Registry of Diabetes. Women with multiple gestations or pregestational diabetes were excluded. Maternal characteristics and risk of T2D were stratified and compared between 3 groups: normal glucose status, OAbV in oGTT, and gestational diabetes. Statistical analysis included univariate analysis followed by survival analysis. Further analysis was stratified to women with and without obesity.

RESULTS

58,693 women entered the analysis. Following an adjustment to maternal age, obesity, hypertension, and hyperlipidemia, OAbV in oGTT was associated with a 1.8-fold increased risk of T2D in a 5-year follow-up compared to normal glucose status. When stratified by obesity, OAbV was associated with a 3.7-fold increase in T2D in women without obesity, however, was no longer a statistically significant predictor of T2D among women with obesity.

CONCLUSIONS

Women with OAbV oGTT during pregnancy are at increased risk for developing T2D over 5 years of follow-up.

Glucose tolerance test with a single abnormal value as a predictor of type 2 diabetes mellitus: a multicenter retrospective study

Clinical implication of a single abnormal value (SAV) in the 100 g oral glucose tolerance test during pregnancy has not been established. We aimed to evaluate the risk of postpartum type 2 diabetes mellitus (T2DM) and investigate adverse pregnancy outcomes in women with SAV, using a retrospective database, from seven medical centers of Korea. Based on the Carpenter-Coustan criteria using two-step approach, pregnancy and postpartum outcomes were compared, among normoglycemic, SAV, and gestational diabetes mellitus (GDM) groups. Among 9353 women, 342 (3.66%) and 418(4.47%) women were included in SAV and GDM groups, respectively. SAV and GDM groups showed significantly higher rates of postpartum T2DM than normoglycemic group (7.60%, 14.83%, and 1.82%, respectively, p < 0.001). And SAV group showed significantly higher rates of pregnancy associated hypertension, preterm birth, and neonatal hypoglycemia and sepsis, compared to normoglycemic group (neonatal sepsis, p = 0.008; the others, p < 0.001). In multivariate analysis, postpartum T2DM was associated with SAV, GDM (with/without insulin), nulliparity, pre-pregnancy BMI, chronic hypertension, hyperlipidemia, and DM family history. A scoring model to predict postpartum T2DM within 5 years, achieved an area under the curve of 0.74. This study demonstrated that not only GDM, but also SAV is a significant risk factor for postpartum T2DM.

Previous High-Intensity Breastfeeding Lowers the Risk of an Abnormal Fasting Glucose in a Subsequent Pregnancy Oral Glucose Tolerance Test

Breastfeeding is associated with reduced lifetime cardiometabolic risk, but little is known regarding the metabolic benefit in a subsequent pregnancy. The primary aim of this study was to investigate the association between breastfeeding duration and intensity and next pregnancy oral glucose tolerance test (OGTT) results. A retrospective cohort study was conducted from March 2020 to October 2022. All multiparous women who met inclusion criteria and gave birth during the study period were eligible for inclusion. Analysis was stratified by risk for gestational diabetes (GDM). High GDM risk criteria included previous GDM and BMI > 35 kg/m2. The association between breastfeeding duration and high-intensity breastfeeding (HIBF) and subsequent pregnancy OGTT were assessed with multivariate logistic models adjusted for statistically and clinically relevant covariables. There were 5374 multiparous participants who met the inclusion criteria for analysis. Of these, 61.7% had previously breastfed for >6 months, and 43.4% were at high risk for GDM. HIBF was associated with 47% reduced odds of an abnormal fasting glucose in a subsequent pregnancy OGTT (aOR 0.53; 95%CI 0.38-0.75; p < 0.01). There was no association between HIBF and other glucose results on the OGTT. Women who smoked were least likely to breastfeed at high intensity (aOR 0.31; 95%CI 0.21-0.47; p < 0.01). South Asian women had 65% higher odds of HIBF than women who identified as White/European (aOR 1.65; 1.36-2.00; p < 0.01). This study highlights the importance of exclusive breastfeeding to potentially reduce the prevalence of GDM and may also translate into long-term reduction of cardiometabolic risk.

Gestational Glucose Intolerance and Risk of Future Diabetes

OBJECTIVE

Pregnant individuals are universally screened for gestational diabetes mellitus (GDM). Gestational glucose intolerance (GGI) (an abnormal initial GDM screening test without a GDM diagnosis) is not a recognized diabetes risk factor. We tested for an association between GGI and diabetes after pregnancy.

RESEARCH DESIGN AND METHODS

We conducted a retrospective cohort study of individuals followed for prenatal and primary care. We defined GGI as an abnormal screening glucose-loading test result at ≥24 weeks' gestation with an oral glucose tolerance test (OGTT) that did not meet GDM criteria. The primary outcome was incident diabetes. We used Cox proportional hazards models with time-varying exposures and covariates to compare incident diabetes risk in individuals with GGI and normal glucose tolerance.

RESULTS

Among 16,836 individuals, there were 20,359 pregnancies with normal glucose tolerance, 2,943 with GGI, and 909 with GDM. Over a median of 8.4 years of follow-up, 428 individuals developed diabetes. Individuals with GGI had increased diabetes risk compared to those with normal glucose tolerance in pregnancy (adjusted hazard ratio [aHR] 2.01 [95% CI 1.54-2.62], P < 0.001). Diabetes risk increased with the number of abnormal OGTT values (zero, aHR 1.54 [1.09-2.16], P = 0.01; one, aHR 2.97 [2.07-4.27], P < 0.001; GDM, aHR 8.26 [6.49-10.51], P < 0.001 for each compared with normal glucose tolerance). The fraction of cases of diabetes 10 years after delivery attributable to GGI and GDM was 8.5% and 28.1%, respectively.

CONCLUSIONS

GGI confers an increased risk of future diabetes. Routinely available clinical data identify an unrecognized group who may benefit from enhanced diabetes screening and prevention.

Early Identification of the Maternal, Placental and Fetal Dialog in Gestational Diabetes and Its Prevention

Gestational diabetes mellitus (GDM) complicates between 5 and 12% of pregnancies, with associated maternal, fetal, and neonatal complications. The ideal screening and diagnostic criteria to diagnose and treat GDM have not been established and, currently, diagnostic use with an oral glucose tolerance test occurs late in pregnancy and produces poor reproducibility. Therefore, in recent years, significant research has been undertaken to identify a first-trimester biomarker that can predict GDM later in pregnancy, enable early intervention, and reduce GDM-related adverse pregnancy outcomes. Possible biomarkers include glycemic markers (fasting glucose and hemoglobin A1c), adipocyte-derived markers (adiponectin and leptin), pregnancy-related markers (pregnancy-associated plasma protein-A and the placental growth factor), inflammatory markers (C-reactive protein and tumor necrosis factor-α), insulin resistance markers (sex hormone-binding globulin), and others. This review summarizes current data on first-trimester biomarkers, the advantages, and the limitations. Large multi-ethnic clinical trials and cost-effectiveness analyses are needed not only to build effective prediction models but also to validate their clinical use.