Markers of Glycemic Control and Neonatal Morbidity in High-Risk Insulin-Resistant Pregnancies

4 vs 7 points self-monitoring blood glucose in gestational diabetes mellitus on diet modification: randomised clinical trial in a single tertiary centre in Malaysia

PURPOSE

There is no standardized best method on monitoring of patients with gestational diabetes on diet modification in the country. This study aims to investigate the optimum method of self-monitoring blood glucose.

METHODS

This is a randomized clinical trial in a single tertiary centre involving patients with gestational diabetes mellitus (GDM) diagnosed based on NICE guideline on diet modification. The patients are randomized in 1:1 ratio to 4 or 7 points self-monitoring blood glucose. The monitoring was required to be done monthly with ultrasound for fetal growth. Blood was taken at recruitment for measurement of serum HbA1c and fructosamine.

RESULTS

A total of 200 patients were recruited. There were significantly more Malay patients in the 7 points group (88.9% vs 78.2%, p = 0.033). Multiparous patients were significantly more in the 4 points group (82.2% vs 68.7%, p = 0.033). Both groups were similar in clinical characteristics. There was no statistical difference in the neonatal outcome particularly fetal macrosomia and admission to neonatal intensive care unit.

CONCLUSIONS

In patients with GDM on diet modification, self-blood glucose monitoring using either 4 or 7 points resulted in similar maternal and perinatal outcomes. The research was registered under ClinicalTrials.gov (NCT04101396) on 17/9/2019 ( https://register.

CLINICALTRIALS

gov/prs/app/action/SelectProtocol?sid=S00098EN&selectaction=Edit&uid=U0004RD4&ts=2&cx=-qlk1w2 ).

The Correlation Between Three-Dimensional Ultrasound Measurement of Fetal Adrenal Gland and Maternal Serum Fructosamine Level in Gestational Diabetes Mellitus: Prospective Cohort Study

OBJECTIVE

Gestational diabetes mellitus (GDM) has an impact on fetal adrenal gland size and volume, which are greater in the GDM population. This study used 2D and 3D ultrasound scanning to determine the correlation of fetal adrenal gland size and volume with fructosamine levels, HbA1c levels, estimated fetal weight (EFW), and neonatal birth weight in GDM patients.

METHODS

This study included eighty singleton pregnant women diagnosed with GDM between 24-28 weeks of gestation. During weeks 32-34 of gestation, the length, width, and depth of the fetal zone and total adrenal gland were measured using transabdominal 2D ultrasound. Virtual organ computer-aided analysis (VOCAL) software was used to evaluate fetal zone and total adrenal gland volume in 3D ultrasound. All the participants were followed until delivery. Pearson's correlation analysis was conducted to examine the correlation between fetal adrenal gland ultrasound measurements and the factors of interest.

RESULTS

The study consisted of sixty-six (82.5%) pregnant women with diet-controlled GDM (GDMA1) and fourteen (17.5%) pregnant women with insulin-managed GDM (GDMA2). There was no difference in fetal adrenal gland measurements between the diet-controlled (GDMA1) and the insulin-managed (GDMA2) groups. All the participants had achieved optimal glucose levels at the time of ultrasound acquisition. The total adrenal gland length and fetal zone volume had statistically significant positive correlations with EFW (r = 0.69, p = 0.02 and r = 0.84, p = 0.01, respectively). After adjusting for EFW, only the fetal zone volume was significantly correlated with fructosamine levels (adjusted-OR = 2.4, 95% CI: 1.5, 3.9, p = 0.01) and HbA1c levels (adjusted-OR = 2.5, 95% CI: 1.6, 4.3, p = 0.01).

CONCLUSION

The fetal zone volume is correlated with EFW, fructosamine levels, and HbA1c levels. This non-invasive technique may be beneficial as an indirect marker for glycemic monitoring in GDM.

Trimester-Specific Serum Fructosamine in Association with Abdominal Adiposity, Insulin Resistance, and Inflammation in Healthy Pregnant Individuals

This study aimed to (1) characterize the variations in serum fructosamine across trimesters and according to pre-pregnancy BMI (ppBMI), and (2) examine associations between fructosamine and adiposity/metabolic markers (ppBMI, first-trimester adiposity, leptin, glucose homeostasis, and inflammation measurements) during pregnancy. Serum fructosamine, albumin, fasting glucose and insulin, leptin, adiponectin, interleukin-6 (IL-6), and C-reactive protein (CRP) concentrations were measured at each trimester. In the first trimester, subcutaneous (SAT) and visceral (VAT) adipose tissue thicknesses were estimated by ultrasound. In the 101 healthy pregnant individuals included (age: 32.2 ± 3.5 y.o.; ppBMI: 25.5 ± 5.5 kg/m2), fructosamine concentrations decreased during pregnancy whereas albumin-corrected fructosamine concentrations increased (p < 0.0001 for both). Notably, fructosamine concentrations were inversely associated with ppBMI, first-trimester SAT, VAT, and leptin (r = −0.55, r = −0.61, r = −0.48, r = −0.47, respectively; p < 0.0001 for all), first-trimester fasting insulin and HOMA-IR (r = −0.46, r = −0.46; p < 0.0001 for both), and first-trimester IL-6 (r = −0.38, p < 0.01). However, once corrected for albumin, most of the correlations lost strength. Once adjusted for ppBMI, fructosamine concentrations were positively associated with third-trimester fasting glucose and CRP (r = 0.24, r = 0.27; p < 0.05 for both). In conclusion, serum fructosamine is inversely associated with adiposity before and during pregnancy, with markers of glucose homeostasis and inflammation, but the latter associations are partially influenced by albumin concentrations and ppBMI.

Novel Biochemical Markers of Glycemia to Predict Pregnancy Outcomes in Women With Type 1 Diabetes

OBJECTIVE

The optimal method of monitoring glycemia in pregnant women with type 1 diabetes remains controversial. This study aimed to assess the predictive performance of HbA_1c, continuous glucose monitoring (CGM) metrics, and alternative biochemical markers of glycemia to predict obstetric and neonatal outcomes.

RESEARCH DESIGN AND METHODS

One hundred fifty-seven women from the Continuous Glucose Monitoring in Women With Type 1 Diabetes in Pregnancy Trial (CONCEPTT) were included in this prespecified secondary analysis. HbA_1c, CGM data, and alternative biochemical markers (glycated CD59, 1,5-anhydroglucitol, fructosamine, glycated albumin) were compared at ∼12, 24, and 34 weeks' gestation using logistic regression and receiver operating characteristic (ROC) curves to predict pregnancy complications (preeclampsia, preterm delivery, large for gestational age, neonatal hypoglycemia, admission to neonatal intensive care unit).

RESULTS

HbA_1c, CGM metrics, and alternative laboratory markers were all significantly associated with obstetric and neonatal outcomes at 24 weeks' gestation. More outcomes were associated with CGM metrics during the first trimester and with laboratory markers (area under the ROC curve generally <0.7) during the third trimester. Time in range (TIR) (63-140 mg/dL [3.5-7.8 mmol/L]) and time above range (TAR) (>140 mg/dL [>7.8 mmol/L]) were the most consistently predictive CGM metrics. HbA_1c was also a consistent predictor of suboptimal pregnancy outcomes. Some alternative laboratory markers showed promise, but overall, they had lower predictive ability than HbA_1c.

CONCLUSIONS

HbA_1c is still an important biomarker for obstetric and neonatal outcomes in type 1 diabetes pregnancy. Alternative biochemical markers of glycemia and other CGM metrics did not substantially increase the prediction of pregnancy outcomes compared with widely available HbA_1c and increasingly available CGM metrics (TIR and TAR).

Review of methods for detecting glycemic disorders

Prediabetes (intermediate hyperglycemia) consists of two abnormalities, impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) detected by a standardized 75-gram oral glucose tolerance test (OGTT). Individuals with isolated IGT or combined IFG and IGT have increased risk for developing type 2 diabetes (T2D) and cardiovascular disease (CVD). Diagnosing prediabetes early and accurately is critical in order to refer high-risk individuals for intensive lifestyle modification. However, there is currently no international consensus for diagnosing prediabetes with HbA1c or glucose measurements based upon American Diabetes Association (ADA) and the World Health Organization (WHO) criteria that identify different populations at risk for progressing to diabetes. Various caveats affecting the accuracy of interpreting the HbA1c including genetics complicate this further. This review describes established methods for detecting glucose disorders based upon glucose and HbA1c parameters as well as novel approaches including the 1-hour plasma glucose (1-h PG), glucose challenge test (GCT), shape of the glucose curve, genetics, continuous glucose monitoring (CGM), measures of insulin secretion and sensitivity, metabolomics, and ancillary tools such as fructosamine, glycated albumin (GA), 1,5- anhydroglucitol (1,5-AG). Of the approaches considered, the 1-h PG has considerable potential as a biomarker for detecting glucose disorders if confirmed by additional data including health economic analysis. Whether the 1-h OGTT is superior to genetics and omics in providing greater precision for individualized treatment requires further investigation. These methods will need to demonstrate substantially superiority to simpler tools for detecting glucose disorders to justify their cost and complexity.

Inverse association between 1,5-anhydroglucitol and neonatal diabetic complications

PURPOSE

A glycemic control marker to predict neonatal diabetic complications is unavailable. We aimed to examine if 1,5-anhydroglucitol (1,5-AG) can predict neonatal complications in women with diabetes in pregnancy.

METHODS

Prospective observational study from December 2011 to August 2013. We recruited 105 women, 70 diabetic (gestational and pregestational) and 35 nondiabetic. 1,5-AG at birth was compared between the two groups. In the diabetic group 1,5-AG, HbA1c, and fructosamine were measured before glycemic control initiation (first visit), after 4-6 weeks (second visit), and at delivery. Women were divided to poor (1,5-AG values below median at birth) and good (1,5-AG values at median and above) glycemic control groups. Mean daily glucose charts were collected. The primary outcome was a composite of neonatal diabetic complications: respiratory distress, hypoglycemia, polycythemia, hyperbilirubinemia, and large for gestational age.

RESULTS

Mean 1,5-AG in the nondiabetic group was similar to that of the diabetic group without the composite outcome and was significantly higher than in the diabetic group with the composite outcome. The rate of the composite outcome was higher in the poor glycemic control group compared with the good glycemic control group (adjusted odds ratio (OR) 3.8 95% CI [1.2-12.3]). Only 1,5-AG was inversely associated with the composite outcome at all time points; the second visit was the only independent risk factor in multivariable logistic regression (OR 0.7 95% CI 0.54-0.91). The rest of the glycemic markers were not associated with neonatal composite outcome.

CONCLUSIONS

1,5-AG is inversely associated with neonatal diabetic complications and is superior to other glycemic markers in predicting those complications.

Mid-Pregnancy Fructosamine Measurement-Predictive Value for Gestational Diabetes and Association with Postpartum Glycemic Indices

Screening for gestational diabetes mellitus (GDM) during pregnancy is cumbersome. Measurement of plasma fructosamine may help simplify the first step of detecting GDM. We aimed to assess the predictive value of mid-pregnancy fructosamine for GDM, and its association with postpartum glycemic indices. Among 1488 women from Project Viva (mean ± SD: 32.1 ± 5.0 years old; pre-pregnancy body mass index 24.7 ± 5.3 kg/m²), we measured second trimester fructosamine and assessed gestational glucose tolerance with a 50 g glucose challenge test (GCT) followed, if abnormal, by a 100 g oral glucose tolerance test (OGTT). Approximately 3 years postpartum (median 3.2 years; SD 0.4 years), we measured maternal glycated hemoglobin (n = 450) and estimated insulin resistance (HOMA-IR; n = 132) from fasting blood samples. Higher glucose levels 1 h post 50 g GCT were associated with higher fructosamine levels (Pearson’s r = 0.06; p = 0.02). However, fructosamine ≥222 µmol/L (median) had a sensitivity of 54.8% and specificity of 48.6% to detect GDM (area under the receiver operating characteristic curve = 0.52); other fructosamine thresholds did not show better predictive characteristics. Fructosamine was also weakly associated with 3-year postpartum glycated hemoglobin (per 1 SD increment: adjusted β = 0.03 95% CI [0.00, 0.05] %) and HOMA-IR (per 1 SD increment: adjusted % difference 15.7, 95% CI [3.7, 29.0] %). Second trimester fructosamine is a poor predictor of gestational glucose tolerance and postpartum glycemic indices.

Biomarkers for Macrosomia Prediction in Pregnancies Affected by Diabetes

Large birthweight, or macrosomia, is one of the commonest complications for pregnancies affected by diabetes. As macrosomia is associated with an increased risk of a number of adverse outcomes for both the mother and offspring, accurate antenatal prediction of fetal macrosomia could be beneficial in guiding appropriate models of care and interventions that may avoid or reduce these associated risks. However, current prediction strategies which include physical examination and ultrasound assessment, are imprecise. Biomarkers are proving useful in various specialties and may offer a new avenue for improved prediction of macrosomia. Prime biomarker candidates in pregnancies with diabetes include maternal glycaemic markers (glucose, 1,5-anhydroglucitol, glycosylated hemoglobin) and hormones proposed implicated in placental nutrient transfer (adiponectin and insulin-like growth factor-1). There is some support for an association of these biomarkers with birthweight and/or macrosomia, although current evidence in this emerging field is still limited. Thus, although biomarkers hold promise, further investigation is needed to elucidate the potential clinical utility of biomarkers for macrosomia prediction for pregnancies affected by diabetes.