Patterns of glucose-lowering therapies and neonatal outcomes in the treatment of gestational diabetes in Canada, 2009-2014

Insulin Use During Gestational and Pre-existing Diabetes in Pregnancy: A Systematic Review of Study Design

INTRODUCTION

Insulin is the first-line pharmacologic therapy for women with diabetes in pregnancy. However, conducting well-designed randomized clinical trials (RCTs) and achieving recommended glycemic targets remains a challenge for this unique population. This systematic literature review (SLR) aimed to understand the evidence for insulin use in pregnancy and the outcome metrics most often used to characterize its effect on glycemic, maternal and fetal outcomes in gestational diabetes mellitus (GDM) and in pregnant women with diabetes.

METHODS

An SLR was conducted using electronic databases in Medline, EMBASE via Ovid platform, evidence-based medicine reviews (2010-2020) and conference proceedings (2018-2019). Studies were included if they assessed the effect of insulin treatment on glycemic, maternal or fetal outcomes in women with diabetes in pregnancy. Studies on any type of diabetes other than gestational or pre-existing diabetes as well as non-human studies were excluded.

RESULTS

In women diagnosed with GDM or pre-existing diabetes, most studies compared treatment of insulin with metformin (n = 35) followed by diet along with lifestyle intervention (n = 24) and glibenclamide (n = 12). Most studies reporting on glycemic outcomes compared insulin with metformin (n = 22) and glibenclamide (n = 4). Fasting blood glucose was the most reported clinical outcome of interest. Among the studies reporting maternal outcomes, method of delivery and delivery complications were most commonly reported. Large for gestational age, stillbirth and perinatal mortality were the most common fetal outcomes reported.

CONCLUSION

This SLR included a total of 108 clinical trials and observational studies with diverse populations and treatment arms. Outcomes varied across the studies, and a lack of consistent outcome measures to manage diabetes in pregnant women was observed. This elucidates a need for global consensus on study design and standardized clinical, maternal and fetal outcomes metrics.

Gestational diabetes: One size does not fit all-an observational study of maternal and neonatal outcomes by maternal glucose profile

OBJECTIVES

To examine obstetrical and neonatal outcomes across maternal glucose profiles at the population level and to explore insulin sensitivity and beta-cell function across profiles in an independent, well-phenotyped cohort for potential pathophysiologic explanation.

RESEARCH DESIGN AND METHODS

Observational cohort study of all pregnancies with gestational diabetes screening between October 2008 and December 2018 resulting in live singleton birth in Alberta, Canada (n = 436,773) were categorized into seven maternal glucose profiles: (1) normal 50 g-glucose challenge test (nGCT), (2) normal 75-g OGTT (nOGTT), (3) isolated elevated 1 h post-load glucose (ePLPG1), (4) isolated elevated 2 h post-load glucose (ePLPG2), (5) elevated 1 and 2 h post-load glucose (ePLPG12), (6) isolated elevated FPG (eFPG), and (7) elevated FPG + elevated 1-h and/or 2-h PLG (Combined). Primary outcomes were large for gestational age (LGA) and neonatal intensive care unit (NICU) admission rates. An independent observational cohort of 1451 women was examined for measures of beta-cell function (ISSI-2, insulinogenic index/HOMA-IR) and insulin sensitivity/resistance (Matsuda index, HOMA-IR) by similar maternal glucose profiles.

RESULTS

Pregnancies with elevated FPG, either isolated or combined, had higher adverse events and lower insulin sensitivity. The combination of elevated FPG + elevated 1-h and/or 2-h PLG had the highest rates of LGA(20.9%), NICU admissions (14.7%), and lowest insulin sensitivity as measured by Matsuda index and HOMA-IR, and beta-cell function as measured by ISSI-2 and Insulinogenic index/HOMA-IR.

CONCLUSIONS

Elevated fasting plasma glucose, either alone or combined with post-load glucose elevation is associated with worse outcomes than isolated post-load glucose elevation, possibly due to higher degrees of insulin resistance. Future work is needed to better understand these differences, and explore whether tailored treatment of GDM can improve neonatal outcomes.

Association Between Maternal Glucose Levels in Gestational Diabetes Screening and Subsequent Hypertension

BACKGROUND

We assessed the association between maternal glucose levels in pregnancy and subsequent hypertension.

METHODS

This population-level, retrospective cohort study examined women aged 12 to 54 years with singleton pregnancies completed at ≥29 weeks of gestation from October 1, 2008 to December 1, 2018 followed until March 31, 2019 in Alberta, Canada. Women were stratified by results in the 50-gram glucose challenge test and by 75-gram oral glucose tolerance test subtypes (normal oral glucose tolerance test, elevated fasting plasma glucose only [elevated fasting], elevated postload glucose only, or both elevated fasting and postload glucose [combined]. Time to development of hypertension was modeled using Cox proportional hazards models.

RESULTS

Of 313 361 women, 231 008 (79.1%) underwent a glucose challenge test only while 60 909 (20.9%) underwent either an oral glucose tolerance test only or both. Nine thousand five hundred eighty (3.1%) developed hypertension, and 2824 (0.9%) developed cardiovascular disease over a median follow-up of 5.7 years. Every 1-mmol/L increase in glucose in the glucose challenge test increased the risk of subsequent hypertension by 15% (adjusted hazard ratio and 95% CI, 1.15 [1.14-1.16]). Among those who underwent the oral glucose tolerance test, the combined group conferred the highest risk of subsequent hypertension, followed by elevated fasting, then elevated postload glucose only (reference: glucose challenge test ≤7.1 mmol/L, adjusted hazard ratio [95% CI]: elevated postload glucose only, 1.83 [1.68-2.00]; elevated fasting 2.02 [1.70-2.40]; combined, 2.65 [2.33-3.01]). No significant associations between maternal glucose levels and cardiovascular disease were observed.

CONCLUSIONS

Increasing maternal glucose levels in pregnancy were associated with increasing risk of subsequent hypertension. These findings may help identify higher-risk women who should be targeted for earlier postpartum cardiovascular risk reduction.

Assisted human reproduction and pregnancy outcomes in Alberta, 2009-2018: a population-based study

BACKGROUND

Assisted human reproduction (AHR) can be used to help individuals and couples overcome infertility issues. We sought to describe trends in pregnancies using AHR and to evaluate the impact of AHR on perinatal outcomes in a large population-based cohort in Alberta, Canada.

METHODS

We linked maternal and child administrative data for all live births occurring July 1, 2009, to Dec. 31, 2018, in Alberta, Canada, for this retrospective study. We identified AHR pregnancies from pharmaceutical claims or codes from the International Classification of Diseases and Related Health Problems (9th or 10th revision). Our main outcome measures were the incidence and temporal trends of live births in AHR pregnancies. We also compared maternal characteristics and perinatal outcomes of AHR and non-AHR pregnancies, and by maternal age group.

RESULTS

Of 518 293 live births during the study period, 26 270 (5.1%) were conceived with AHR. The incidence of AHR pregnancies increased from 30.8 per 1000 pregnancies in 2009 to 54.7 per 1000 pregnancies in 2018. Females who used AHR were older (33.9 yr v. 30.1 yr, p < 0.001) and the number of females aged 30-35 years and older than 35 years who delivered following AHR increased over the study period (30-35 yr: 36.9 to 55.3 per 1000 pregnancies; > 35 yr: 79.1 to 95.2 per 1000 pregnancies). The proportion of live births with cesarean delivery (40.5% v. 23.3%, p < 0.001), low birth weight (26.9% v. 7.6%, p < 0.001), congenital malformation (0.5% v. 0.3%, p = 0.002) and admission to the neonatal intensive care unit (25.3% v. 9.7%, p < 0.001) was higher in the AHR group than the non-AHR group.

INTERPRETATION

The incidence of live births following AHR pregnancies in Alberta was 5.1% between 2009 and 2018, and increased by 0.26% per year; newborns in the AHR group appeared smaller and showed signs of poorer health. This study provides insights on potential perinatal complications following AHR that may be important when caring for the newborn child.

Inappropriate use of clinical practices in Canada: a systematic review

Background:

Inappropriate health care leads to negative patient experiences, poor health outcomes and inefficient use of resources. We aimed to conduct a systematic review of inappropriately used clinical practices in Canada.

Methods:

We searched multiple bibliometric databases and grey literature to identify inappropriately used clinical practices in Canada between 2007 and 2021. Two team members independently screened citations, extracted data and assessed methodological quality. Findings were synthesized in 2 categories: diagnostics and therapeutics. We reported ranges of proportions of inappropriate use for all practices. Medians and interquartile ranges (IQRs), based on the percentage of patients not receiving recommended practices (underuse) or receiving practices not recommended (overuse), were calculated. All statistics are at the study summary level.

Results:

We included 174 studies, representing 228 clinical practices and 28 900 762 patients. The median proportion of inappropriate care, as assessed in the studies, was 30.0% (IQR 12.0%–56.6%). Underuse (median 43.9%, IQR 23.8%–66.3%) was more frequent than overuse (median 13.6%, IQR 3.2%–30.7%). The most frequently investigated diagnostics were glycated hemoglobin (underused, range 18.0%–85.7%, n = 9) and thyroid-stimulating hormone (overused, range 3.0%–35.1%, n = 5). The most frequently investigated therapeutics were statin medications (underused, range 18.5%–71.0%, n = 6) and potentially inappropriate medications (overused, range 13.5%–97.3%, n = 9).

Interpretation:

We have provided a summary of inappropriately used clinical practices in Canadian health care systems. Our findings can be used to support health care professionals and quality agencies to improve patient care and safety in Canada.

Computing the polytomous discrimination index

Polytomous regression models generalize logistic models for the case of a categorical outcome variable with more than two distinct categories. These models are currently used in clinical research, and it is essential to measure their abilities to distinguish between the categories of the outcome. In 2012, van Calster et al proposed the polytomous discrimination index (PDI) as an extension of the binary discrimination c-statistic to unordered polytomous regression. The PDI is a summary of the simultaneous discrimination between all outcome categories. Previous implementations of the PDI are not capable of running on "big data." This article shows that the PDI formula can be manipulated to depend only on the distributions of the predicted probabilities evaluated for each outcome category and within each observed level of the outcome, which substantially improves the computation time. We present a SAS macro and R function that can rapidly evaluate the PDI and its components. The routines are evaluated on several simulated datasets after varying the number of categories of the outcome and size of the data and two real-world large administrative health datasets. We compare PDI with two other discrimination indices: M-index and hypervolume under the manifold (HUM) on simulated examples. We describe situations where the PDI and HUM, indices based on multiple comparisons, are superior to the M-index, an index based on pairwise comparisons, to detect predictions that are no different than random selection or erroneous due to incorrect ranking.

Diabetes after pregnancy: a study protocol for the derivation and validation of a risk prediction model for 5-year risk of diabetes following pregnancy

BACKGROUND

Pregnancy offers a unique opportunity to identify women at higher future risk of type 2 diabetes mellitus (DM). In pregnancy, a woman has greater engagement with the healthcare system, and certain conditions are more apt to manifest, such as gestational DM (GDM) that are important markers for future DM risk. This study protocol describes the development and validation of a risk prediction model (RPM) for estimating a woman's 5-year risk of developing type 2 DM after pregnancy.

METHODS

Data will be obtained from existing Ontario population-based administrative datasets. The derivation cohort will consist of all women who gave birth in Ontario, Canada between April 2006 and March 2014. Pre-specified predictors will include socio-demographic factors (age at delivery, ethnicity), maternal clinical factors (e.g., body mass index), pregnancy-related events (gestational DM, hypertensive disorders of pregnancy), and newborn factors (birthweight percentile). Incident type 2 DM will be identified by linkage to the Ontario Diabetes Database. Weibull accelerated failure time models will be developed to predict 5-year risk of type 2 DM. Measures of predictive accuracy (Nagelkerke's R2), discrimination (C-statistics), and calibration plots will be generated. Internal validation will be conducted using a bootstrapping approach in 500 samples with replacement, and an optimism-corrected C-statistic will be calculated. External validation of the RPM will be conducted by applying the model in a large population-based pregnancy cohort in Alberta, and estimating the above measures of model performance. The model will be re-calibrated by adjusting baseline hazards and coefficients where appropriate.

DISCUSSION

The derived RPM may help identify women at high risk of developing DM in a 5-year period after pregnancy, thus facilitate lifestyle changes for women at higher risk, as well as more frequent screening for type 2 DM after pregnancy.

Trends in pregnancy outcomes for women with gestational diabetes mellitus in Sweden 1998-2012: a nationwide cohort study

AIM

To assess whether incidence of maternal and neonatal outcomes for women with or without gestational diabetes mellitus (GDM) have changed over time.

METHODS

Population-based cohort study in Sweden including all singleton pregnancies over the period 1998-2012. GDM was diagnosed following Diabetic Pregnancy Study Group 1991 criteria. Poisson regression or negative binomial regression was used to model yearly relative change in numbers of cases and incidence of the outcomes with 95% confidence intervals (CI), and yearly absolute change in birthweight z-score.

RESULTS

The study included 1 455 667 pregnancies. The number of pregnancies increased over time and the overall prevalence of GDM was 1%. For women with GDM there was a significantly decreasing trend in incidence per year for large for gestational age (LGA) (0.986, 95% CI 0.975 to 0.996), birthweight z-score (-0.012, 95% CI -0.017 to -0.007) and birth trauma (0.937, 95% CI 0.907 to 0.968). The trend for small for gestational age (SGA) among women with GDM increased by an odds ratio per year (1.016, 95% CI 1.002 to 1.029). No significant interaction tests for maternal characteristics were found. Trends in outcomes for women without diabetes were similar to those for women with GDM.

CONCLUSIONS

This study shows that there were improvements in pregnancy outcomes for women with GDM between 1998 and 2012, although the incidence of SGA increased. Improvements followed similar trends in the background population. Inequalities in obstetric outcomes between women with GDM and those without have continued unchanged over 15 years, suggesting that new management strategies are required to reduce this gap.

Elevated fasting vs post-load glucose levels and pregnancy outcomes in gestational diabetes: a population-based study

AIMS

To examine the relative association between fasting plasma glucose vs post-load (1-h and 2-h) glucose levels based on the oral glucose tolerance test in pregnancy and large-for-gestational-age and hypertensive disorders of pregnancy outcomes.

METHODS

All live singleton births between October 2008 and December 2014 in Alberta, Canada were included. Gestational diabetes mellitus was diagnosed using Diabetes Canada criteria. Logistic regression models were used to examine the association between fasting plasma glucose vs post-load values and large-for-gestational-age infants and hypertensive disorders of pregnancy after adjusting for maternal characteristics and pharmaceutical intervention in gestational diabetes pregnancies.

RESULTS

Among 257 547 pregnancies, 208 344 (80.9%) had negative 50-g glucose challenge tests, 36 261 (14.1%) had negative 75-g oral glucose tolerance tests, and 12 942 (5.0%) had gestational diabetes based on either elevated fasting plasma glucose (n=4130, 1.6%) or elevated 1-h and/or 2-h oral glucose tolerance test values (n=8812, 3.4%). Large-for-gestational-age and hypertensive disorders of pregnancy rates were 8.1% and 5.1% in negative glucose challenge test pregnancies, 11.0% and 7.0% in negative oral glucose tolerance test pregnancies, 22.4% and 11.9% in gestational diabetes pregnancies with elevated fasting plasma glucose, and 9.1% and 8% in gestational diabetes pregnancies with elevated post-load levels, respectively. Among gestational diabetes pregnancies, those with elevated fasting plasma glucose were at higher risk of large-for-gestational age (adjusted odds ratio 2.66, 95% CI 2.39-2.96) and hypertensive disorders of pregnancy (adjusted odds ratio 1.51, 95% CI 1.33-1.72) outcomes relative to pregnancies with post-load glucose elevations only. Fasting plasma glucose remained significantly associated with adverse outcomes in gestational diabetes pregnancies with and without pharmacological intervention.

CONCLUSIONS

Elevated fasting plasma glucose in women with gestational diabetes is a stronger predictor of large-for-gestational-age and hypertensive disorders of pregnancy outcomes than elevated post-load glucose.

A Population-level Analysis of the Differing Effects of Rheumatoid Arthritis and Spondyloarthritis on Peripartum Outcomes

OBJECTIVE

The effects of rheumatoid arthritis (RA) and spondyloarthritis (SpA) on maternal and neonatal outcomes at a population level have not previously been well compared.

METHODS

A contemporary pregnancy cohort of 312,081 women and corresponding birth events was assembled for the province of Alberta from the random selection of 1 live birth event per woman. We identified 3 groups: (1) no inflammatory arthritis (no IA, n = 308,989), (2) RA (n = 631), and (3) SpA (n = 2461). We compared maternal and neonatal outcomes, comorbid conditions, and medication use among the 3 groups. Multivariable logistic regression models evaluated the independent association between RA and SpA, relative to no IA, and the outcomes of small for gestation age (SGA) and hypertensive disorders during pregnancy.

RESULTS

Pregnant women with RA were significantly more likely to have preterm delivery (13.5%), cesarean delivery (33.9%), hypertensive disorders in pregnancy (10.5%), and SGA babies (15.6%), compared to pregnant women with either SpA or no IA. Nonsteroidal antiinflammatory drugs and corticosteroid use were significantly higher in pregnant women with RA compared to the other groups. Women with RA were significantly more likely to have an SGA baby (OR 1.51, 95% CI 1.21-1.88; p < 0.01), and hypertensive disorder in pregnancy (OR 1.51, 95% CI 1.16-1.97; p < 0.01), compared to women with no IA, while no difference was found between women with SpA and those with no IA.

CONCLUSION

Women with RA have a higher risk of worse maternal and neonatal outcomes, whereas the risk of these events is similar between women with and without SpA.

Association between maternal diabetes, being large for gestational age and breast-feeding on being overweight or obese in childhood

AIMS/HYPOTHESIS

This study aimed to examine the association of maternal diabetes, being large for gestational age (LGA) and breast-feeding with being overweight or obese in pre-school-aged children.

METHODS

Data on height and weight at the time of their pre-school (age 4-6 years) immunisation visit between January 2009 and August 2017, as well as breast-feeding status in the first 5 months of life, for 81,226 children born between January 2005 and August 2013 were linked with maternal hospitalisation and outpatient records and birth registry data. Children were grouped into six categories based on maternal diabetes status during pregnancy (no diabetes, gestational diabetes or pre-existing diabetes) and birthweight (appropriate for gestational age [AGA] or LGA). WHO criteria were used to identify children who were overweight or obese.

RESULTS

There were 69,506 children in the no diabetes/AGA group (control), 5926 in the no diabetes/LGA group, 4563 in the gestational diabetes/AGA group, 573 in the gestational diabetes/LGA group, 480 in the pre-existing diabetes/AGA group and 178 in the pre-existing diabetes/LGA group. The rate of being overweight/obese at pre-school age ranged from 20.5% in the control group to 42.9% in the gestational diabetes/LGA group. The adjusted attributable risk per cent for LGA alone (39.4%) was significantly higher than that for maternal gestational diabetes (16.0%) or pre-existing diabetes alone (15.1%); the risk for the combinations of gestational diabetes/LGA and pre-existing diabetes/LGA were 50.1% and 39.1%, respectively. Further stratification of the pre-existing diabetes groups found the prevalence of being overweight/obese was 21.2% in the type 1/AGA group, 31.4% in the type 1/LGA group (similar to those in the no diabetes groups), 26.7% in the type 2/AGA group and 42.5% in the type 2/LGA group. Breast-feeding was associated with a lower likelihood of being overweight/obese in childhood in all groups except gestational diabetes/LGA and pre-existing diabetes/LGA (both type 1 and type 2).

CONCLUSION/INTERPRETATION

LGA is a stronger marker for risk of being overweight/obese in early childhood, compared with maternal diabetes during pregnancy. Rates of being overweight/obese in childhood were highest in LGA children born to mothers with gestational diabetes or pre-existing type 2 diabetes. Breast-feeding was associated with a lower risk of being overweight/obese in childhood in the majority of children; however, this association was not maintained in LGA children of mothers with diabetes.

Prevalence of newly detected diabetes in pregnancy in Qatar, using universal screening

Background

Diabetes first detected during pregnancy is currently divided into gestational diabetes mellitus (GDM) and diabetes mellitus (DM)- most of which are type 2 DM (T2DM). This study aims to define the prevalence and outcomes of diabetes first detected in pregnancy based on 75-gram oral glucose tolerance test (OGTT)using the recent WHO/IADPSG guidelines in a high-risk population.

Methods

This is a retrospective study that included all patients who underwent a 75 g (OGTT) between Jan 2016 and Apr 2016 and excluded patients with known pre-conception diabetes.

Results

The overall prevalence of newly detected diabetes in pregnancy among the 2000 patients who fulfilled the inclusion/exclusion criteria was 24.0% (95% CI 22.1–25.9) of which T2DM was 2.5% (95% CI 1.9–3.3), and GDM was 21.5% (95% CI 19.7–23.3). The prevalence of newly detected diabetes in pregnancy was similar among the different ethnic groups.

The T2DM group was older (mean age in years was 34 ±5.7 vs 31.7±5.7 vs 29.7 ±5.7, p<0.001); and has a higher mean BMI (32.4±6.4 kg/m2 vs 31.7±6.2 kg/m2 vs 29.7± 6.2 kg/m2, p< 0.01) than the GDM and the non-DM groups, respectively. The frequency of pre-eclampsia, pre-term delivery, Caesarean-section, macrosomia, LGA and neonatal ICU admissions were significantly higher in the T2DM group compared to GDM and non-DM groups.

Conclusion

Diabetes first detected in pregnancy is equally prevalent among the various ethnic groups residing in Qatar. Newly detected T2DM carries a higher risk of poor pregnancy outcomes; stressing the importance of proper classification of cases of newly detected diabetes in pregnancy.