Screening for gestational diabetes in Tuscany, Italy. A population study

Commentary from the Italian Association of Medical Diabetologists (AMD) and Italian Society of Diabetology (SID) Interassociative Diabetes and Pregnancy Study Group on the screening and diagnostic methods for gestational diabetes: An open debate

The current board of the interassociative Italian association of medical diabetologists (AMD)/Italian society of diabetology (SID) Diabetes and Pregnancy Italian Study Group commented about two recent papers published in the New England Journal of Medicine that investigated the screening and diagnostic methods for gestational diabetes mellitus (GDM). It is well recognized that effective screening and accurate, early diagnosis of GDM contributes to better management of these women in order to reduce adverse maternal and fetal/neonatal outcomes. However, there is worldwide controversy concerning which screening (selective or universal; one step or two steps) and which diagnostic criteria (glucose thresholds) are appropriate. The main findings of these papers are discussed along with their implications for the management of pregnant women.

Pregestational exposure to hormonal combined contraceptives and risk of gestational diabetes: an observational retrospective population study

AIMS

To investigate whether pregestational exposure to oral combined hormonal contraception (CHC) is associated with a rise in the risk of gestational diabetes (GDM).

METHODS

Prevailing GDM was assessed for all pregnancies that occurred in Tuscany, Italy, from years 2010 to 2018, using administrative data coupled with information about CHC prescriptions in the year prior to pregnancy retrieved from the regional registry of drug prescription claims. The relation between exposure to CHC and risk of GDM, expressed as Odds Ratio: OR (95% Confidence Intervals, CI), was calculated separately based on citizenship of mothers using multiple logistic regression analysis models, after adjusting for confounders.

RESULTS

Among 210,791 pregnancies from 170,126 mothers, GDM was present in 22,166 (10.5%) pregnancies. CHC prescription within 12 months before the index pregnancy was present in 9065 (4.3%) mothers. The risk of GDM was weakly but significantly higher in pregnancies exposed to pregestational CHC only in pregnancies of mothers of Italian citizenship: OR:1.11 (95% CI 1.02-1.21); p = 0.02, after adjusting for age, parity, calendar year and pregestational body-mass index. The CHC-mediated effect was no longer present in pregnancies of mothers at higher risk of GDM, such as pregestational obesity, migrating from countries at higher GDM risk or after adjusting for the entire panel of confounders including employment status, prior spontaneous abortions, and education degree.

CONCLUSIONS

CHC had a modest effect on GDM risk, which became insignificant when added to basal prevailing risk factors for impaired glucose metabolism in pregnancy, such as pregestational obesity or originating from countries at high GDM risk.

Evolution of Gestational Diabetes Mellitus across Continents in 21st Century

Over the last few decades, several definitions of gestational diabetes mellitus (GDM) have been described. There is currently not enough research to show which way is the best to diagnose GDM. Opinions differ in terms of the optimal screening and diagnostic measures, in part due to the differences in the population risks, the cost-effectiveness considerations, and the lack of an evidence base to support large national screening programs. The basic method for identifying the disease is the measurement of glucose plasma levels which may be determined when fasting, two hours after a meal, or simply at any random time. The currently increasing incidence of diabetes in the whole population, the altering demographics and the presence of lifestyle changes still require better methods of screening for hyperglycemia, especially during pregnancy. The main aim of this review is to focus on the prevalence and modifications to the screening criteria for GDM across all continents in the 21st century. We would like to show the differences in the above issues and correlate them with the geographical situation. Looking at the history of diabetes, we are sure that more than one evolution in GDM diagnosis will occur, due to the development of medicine, appearance of modern technologies, and the dynamic continuation of research.

The impact of fetal sex on risk factors for gestational diabetes and related adverse pregnancy outcomes

AIMS

To investigate whether fetal sex affects the impact of classical GDM risk factors on the diagnosis of gestational diabetes (GDM) as well as on related adverse pregnancy outcomes.

METHODS

This retrospective observational study concerned 206,917 singleton live births born to 170,126 women aged 15-45 over the years 2010-2018 in Tuscany, Italy. GDM was identified by administrative data-sources in 21,613 pregnancies (10.5%) by assessing, through multiple logistic models, whether fetal sex modified the risk of GDM driven by maternal risk factors, and whether it modified the risk of adverse outcomes such as prematurity (birth ≤ 37th gestational week), large for gestational age (LGA), unplanned caesarean sections, or 5-min-Apgar-index ≤ 7 in pregnancies with GDM.

RESULTS

GDM was diagnosed in 21,613 pregnancies (10.5%). Male fetal sex predicted a higher adjusted risk of GDM: OR = 1.05(95% CI: 1.01-1.07); p < 0.0009. In pregnancies with female sex, pre-pregnancy obesity amplified the risk of GDM: OR = 1.09(95% CI: 1.01-1.19); p =  0.04. In pregnancies with GDM, carrying a female fetus increased the risk of LGA associated with pregestational obesity OR = 1.45(95% CI: 1.15-1.81); p = 0.001, and in primiparous pregnancies, it protected mothers from the risk of unplanned caesarean sections OR = 0.80(95%CI: 0.67-0.92); p = 0.001.

CONCLUSIONS

While male fetal sex is associated with rise in the risk of GDM, giving birth to a girl amplifies the excess GDM risk driven by pregestational obesity, thus increasing the risk of LGA in pregnancies with GDM. Additionally, female fetal sex in pregnancies with GDM seems to protect from the risk of unplanned caesarean sections in primiparous pregnancies.

Gestational Diabetes Mellitus in Europe: A Systematic Review and Meta-Analysis of Prevalence Studies

Background

Gestational Diabetes Mellitus (GDM) is defined as the type of hyperglycemia diagnosed for the first-time during pregnancy, presenting with intermediate glucose levels between normal levels for pregnancy and glucose levels diagnostic of diabetes in the non-pregnant state. We aimed to systematically review and meta-analyze studies of prevalence of GDM in European countries at regional and sub-regional levels, according to age, trimester, body weight, and GDM diagnostic criteria.

Methods

Systematic search was conducted in five databases to retrieve studies from 2014 to 2019 reporting the prevalence of GDM in Europe. Two authors have independently screened titles and abstracts and full text according to eligibility using Covidence software. A random-effects model was used to quantify weighted GDM prevalence estimates. The National Heart, Lung, and Blood Institute criteria was used to assess the risk of bias.

Results

From the searched databases, 133 research reports were deemed eligible and included in the meta-analysis. The research reports yielded 254 GDM-prevalence studies that tested 15,572,847 pregnant women between 2014 and 2019. The 133 research reports were from 24 countries in Northern Europe (44.4%), Southern Europe (27.1%), Western Europe (24.1%), and Eastern Europe (4.5%). The overall weighted GDM prevalence in the 24 European countries was estimated at 10.9% (95% CI: 10.0-11.8, I2 : 100%). The weighted GDM prevalence was highest in the Eastern Europe (31.5%, 95% CI: 19.8-44.6, I2 : 98.9%), followed by in Southern Europe (12.3%, 95% CI: 10.9-13.9, I2 : 99.6%), Western Europe (10.7%, 95% CI: 9.5-12.0, I2 : 99.9%), and Northern Europe (8.9%, 95% CI: 7.9-10.0, I2 : 100). GDM prevalence was 2.14-fold increased in pregnant women with maternal age ≥30 years (versus 15-29 years old), 1.47-fold if the diagnosis was made in the third trimester (versus second trimester), and 6.79- fold in obese and 2.29-fold in overweight women (versus normal weight).

Conclusions

In Europe, GDM is significant in pregnant women, around 11%, with the highest prevalence in pregnant women of Eastern European countries (31.5%). Findings have implications to guide vigilant public health awareness campaigns about the risk factors associated with developing GDM.

Systematic Review Registration

PROSPERO [https://www.crd.york.ac.uk/PROSPERO/], identifier CRD42020161857.

Awareness of gestational diabetes mellitus foetal-maternal risks: an Italian cohort study on pregnant women

Background

Gestational diabetes mellitus (GDM) incidence is increasing worldwide. It represents a major risk factor for adverse foetal-maternal outcomes. Awareness among women in regard to GDM-related risks (in particular foetus ones) has been proven to have an impact on compliance with recommendations. Therefore we aimed to evaluate the efficacy of our post-diagnosis counselling, that informs affected women of the GDM related risks for complications, in determining an adequate level of understanding.

Method

This is a cohort study involving 400 women undergoing the 24-28 weeks 75 g oral glucose tolerance test. Two hundred women diagnosed with GDM received the post-diagnosis counselling (treatment group) and two hundred women diagnosed without did not receive any counselling (control group). Both populations were surveyed with a 5 question questionnaire regarding their awareness about GDM foetal-maternal related risks. Their level of education about GDM foetal-maternal related risks, estimated according to the number of correct answers, was scored as: primary (score 0-1), secondary (score 2-3) or tertiary (score 4-5).

Results

Most of the women in the treatment group after receiving the post-diagnosis counselling have demonstrated a secondary level of education 132/200 (66%). Their mean level of awareness was higher in comparison to the control group 2.6 ± 1.8 (SD) versus 2.14 ± 1.8 (SD) p value = 0.012. In particular, they’ve demonstrated to be more aware of the risks for the foetus to become macrosomic (p = 0.004) or to die in utero (p = 0.0001). A high level of education and to have had previous pregnancies positively affected correct answers.

Conclusions

Our post-diagnosis counselling has played a role in improving women awareness about GDM foetal-maternal related risks. Future study will explore the impact of women’s level of awareness on glycaemic control.

Pregnancy outcomes and maternal characteristics in women with pregestational and gestational diabetes: a retrospective study on 206,917 singleton live births

AIMS

To examine risk of adverse pregnancy outcomes, mothers' characteristics and incidence rate over time of pregestational type 1 (T1D), type 2 (T2D) or gestational diabetes (GDM).

METHODS

The study included all singleton live births born from women aged 15-45 year, in Tuscany, Italy from 2010 to 2018. Pregnancy outcomes were retrieved by certificates of care at delivery compiled by midwives. Pregestational diabetes and GDM were identified by regional administrative databases. Time course of pregestational diabetes and GDM across last decade was assessed by Poisson analysis. Logistic regression analysis was used to calculate adjusted odds ratios (OR; 95% CI) for maternal characteristics or neonatal outcomes.

RESULTS

Among 206,917 singleton live births, GDM was diagnosed in 21,613 pregnancies (10.46%) and pregestational diabetes in 979, being T2D more prevalent than T1D (606; 0.29% vs. 373; 0.18%). Pregestational T2D incidence progressively decreased over last decade, T1D remained stable while GDM progressively rose. Pre-pregnancy obesity, preterm deliveries or cesarean sections were common characteristics of pregestational diabetes and GDM. Risk of neonatal distress and neonatal malformations was higher in pregestational T1D. Risk of prior spontaneous abortions was higher in GDM and in pregestational T2D (OR: 4.19; 3.30-5.33), mostly treated with metformin. Risk of neonatal macrosomia was increased only in pregestational diabetes.

CONCLUSIONS

In our population, pregestational T2D was more prevalent than T1D. Neonatal complications were mostly associated with pregestational T1D. Increased risk of previous spontaneous abortions was the hallmark of pregestational T2D. GDM, even if sharing adverse outcomes with pregestational T2D, was unrelated to rise in risk of neonatal macrosomia.

Incidental diagnosis of a pancreatic adenocarcinoma in a woman affected by gestational diabetes mellitus: case report and literature review

Pancreatic cancer is rarely diagnosed during pregnancy; it usually manifests with symptoms such as epigastric pain, vomiting, weight loss, and jaundice, rarely mimicking the hemolysis, elevated liver enzymes, and low platelet count syndrome. It has been postulated that there exists a correlation between the diagnosis of gestational diabetes mellitus and the occurrence of pancreatic cancer later in life. We conducted an expert literature review of the 31 available documented pancreatic cancer cases that were diagnosed during pregnancy. We also report pancreatic adenocarcinoma incidentally suspected in an asymptomatic woman affected by gestational diabetes mellitus; the woman was undergoing a fetal growth scan.

Materno-Fetal and Neonatal Complications of Diabetes in Pregnancy: A Retrospective Study

The aim of this case-control study was to evaluate maternal-fetal and neonatal clinical outcomes in a group of patients with gestational diabetes mellitus (GDM) and pregestational diabetes such as diabetes mellitus type 1 (DM1) and diabetes mellitus type 2 (DM2) and compare them with those of patients without diabetes. A total of 414 pregnant women, nulliparous and multiparous, with single pregnancy were recruited. The selected patients were divided into two groups. Among 207 patients (group cases), 183 had GDM and 24 pregestational diabetes (of which n = 17 diagnosed with DM1 and n = 7 with diagnosis of DM2). Two-hundred-seven patients with a negative pathologic history of GDM, DM1 and DM2 represented the population of controls (group control). We reported an incidence of preterm delivery of 23.2% in the group of cases, of 18.3% in the group of patients with GDM and 66.7% in the group of patients DM1/2. Fetal growth disorders, such as intrauterine growth retardation (IUGR), small for gestational age (SGA), fetal macrosomia, were detected in four fetuses out of 207 (1.93%) in the control group and 20 fetuses out of 207 in the case group (9.67%, p-value 0.001); of these 16 of 183 fetuses of the GDM group (8.74%, p-value 0.002) and 4 of 24 fetuses of the DM1/2 group (16.67%, p-value 0.005). A very strong correlation between diabetes mellitus type 1 and preeclampsia (p-value < 0.0001) was observed. Close monitoring of pregnant women with diabetes is recommended to prevent maternal-fetal and neonatal complications.

Risk and adverse outcomes of gestational diabetes in migrants: A population cohort study

AIMS

To evaluate the risk of gestational diabetes (GDM) and of neonatal/maternal complications (macrosomia, large for gestational age (LGA), cesarean sections, preterm deliveries, neonatal distress and fetal malformations) among women coming from High Migration Pressure Countries (HMPC), compared to native (Italian) mothers.

METHODS

Risks of GDM and related neonatal/maternal complications were evaluated in a cohort of 581,073 Italian compared with 105,111 HMPC women of age 15-45 yr, resident in Tuscany, Italy along years 2012-2017, delivering 122,652 singleton live births (18,596 from HMPC mothers).

RESULTS

HMPC women, compared to Italian ones, were at higher risk of GDM (OR: 1.586; 1.509-1.666;p < 0.0001), peaking for women originating from South Asia (OR:3.0.49; 2.618-3.553;p < 0.0001). GDM was associated with increased risk of preterm delivery and cesarean sections, while migrants, regardless of GDM, were burdened by a higher risk of all considered complications. The rise in all these risks, including macrosomia or LGA however, disappeared, after addition of interaction term GDM × HMPC ethnicity.

CONCLUSION

Compared to Italian mothers, HMPC women had higher risk of GDM and of all considered adverse events. The addiction of the interaction term GDM × HMPC ethnicity in the predictive model, however reversed the rise in risk of all HMPC associated adverse outcomes.

Guidelines for the screening and diagnosis of gestational diabetes in Italy from 2010 to 2019: critical issues and the potential for improvement

AIMS

In 2010, Italian health professionals rapidly implemented the one-step screening for gestational diabetes mellitus (GDM) based on a 75 g OGTT, to comply with the diagnostic criteria proposed by the International Association of Diabetes and Pregnancy Study Groups (IADPSG). The change was promoted by the two main Italian scientific societies of diabetology, Associazione Medici Diabetologi (AMD) and Società Italiana di Diabetologia (SID), and it took just a few months for the Istituto Superiore di Sanità, together with several scientific societies, to revise the criteria and include them in the National Guidelines System. Over the last 9 years, the implementation of these guidelines has shown some benefits and some drawbacks.

METHODS

In order to evaluate the critical issues arisen from the implementation of the current Italian guidelines for the diagnosis of GDM, the studies published on this topic have been reviewed. The search was performed using the following keywords: "gestational diabetes" AND "diagnostic criteria" OR screening AND Ital*. The study is an expert opinion paper, based on the relevant scientific literature published between 2010 and 2019. The databases screened for the literature review included PubMed, MEDLINE, and Scopus.

RESULTS

The implementation of the Guidelines for Screening and Diagnosis of GDM in Italy present some strengths and some weaknesses. One of the positive aspects is that high-risk women are required to perform an OGTT early in pregnancy. By contrast, there are several aspects in need of improvement: (1) In spite of the current indications, only a minority of high-risk women perform OGTT early in pregnancy; (2) several low-risk women are screened for GDM; (3) in some low-risk women affected by GDM, the diagnosis might be missed with the application of the current guidelines; (4) there is a lack of homogeneity in the risk assessment data from different regions.

CONCLUSIONS

In order to improve the current Italian GDM guidelines, some practical solutions have been suggested.

The impact of differences in plasma glucose between glucose oxidase and hexokinase methods on estimated gestational diabetes mellitus prevalence

We evaluated the extent of measurement discordance between glucose oxidase and hexokinase laboratory methods and the effect of this on estimated gestational diabetes mellitus (GDM) prevalence in a routine clinical setting. 592 consecutive urban African women were screened for GDM. Paired venous specimens were submitted to two independent calibrated laboratories that used either method to measure plasma glucose concentrations. World Health Organisation diagnostic criteria were applied. GDM prevalence determined by the glucose oxidase and hexokinase methods was 6.9% and 5.1% respectively. The overall GDM prevalence was 9%. Only 34% of GDM positive diagnoses were common to both laboratory methods. Bland Altman plots identified a bias of 0.2 mmol/l between laboratory methods. Plasma glucose concentrations measured by the glucose oxidase method were more platykurtic in distribution. Low diagnostic agreement between laboratory methods was further indicated by a Cohen’s kappa of 0.48 (p < 0.001). Reports of GDM prevalence using either the glucose oxidase or hexokinase laboratory methods may not be truly interchangeable or directly comparable.

The post-HAPO situation with gestational diabetes: the bright and dark sides

AIM

In 2010, in light of the data coming from the HAPO study, the International Association of Diabetes and Pregnancy Study Groups (IADPSG) proposed a new detection strategy and diagnostic criteria for gestational diabetes based on a one-step approach with a 75 g OGTT. This review analyzes and discusses the bright and dark sides of their application.

METHODS

The assessment of these recommendations by the international organizations involved in the care of gestational diabetes and a series of observational, retrospective and prospective studies that have been published since 2010 regarding the use of the IADPSG recommendations have been evaluated.

RESULTS

The different international associations involved in the care of pregnancy and of pregnancy complicated by diabetes have not taken an univocal position some of which have accepted them, while others have criticized them. Then, the actual application of the approach recommended by the IADPSG for detecting and diagnosing GDM varies, even at centers that reportedly accept the new diagnostic criteria.

CONCLUSION

So the challenge lies in making every effort to achieve a global standardization of the strategies for detecting, diagnosing and treating GDM.

The short-term economic burden of gestational diabetes mellitus in Italy

Background

The incidence of Gestational Diabetes Mellitus (GDM) is rising in all developed countries. This study aimed at assessing the short-term economic burden of GDM from the Italian healthcare system perspective.

Methods

A model was built over the last pregnancy trimester (i.e., from the 28th gestational week until childbirth included). The National Hospital Discharge Database (2014) was accessed to estimate delivery outcome probabilities and inpatient costs in GDM and normal pregnancies (i.e., euglycemia). International Classification of Disease-9th Revision-Clinical Modification (ICD9-CM) diagnostic codes and Diagnosis-Related Group (DRG) codes were used to identify GDM cases and different types of delivery (i.e., vaginal or cesarean) within the database. Neonatal outcomes probabilities were estimated from the literature and included macrosomia, hypoglycemia, hyperbilirubinemia, shoulder dystocia, respiratory distress, and brachial plexus injury. Additional data sources such as regional documents, official price and tariff lists, national statistics and expert opinion were used to populate the model. The average cost per case was calculated at national level to estimate the annual economic burden of GDM. One-way sensitivity analyses and Monte Carlo simulations were performed to quantify the uncertainty around base case results.

Results

The amount of pregnancies complicated by GDM in Italy was assessed at 54,783 in 2014 using a prevalence rate of 10.9%. The antenatal outpatient cost per case was estimated at €43.7 in normal pregnancies compared to €370.6 in GDM patients, which is equivalent to a weighted sum of insulin- (14%; €1034.6) and diet- (86%; €262.5) treated women’s costs. Inpatient delivery costs were assessed at €1601.6 and €1150.3 for euglycemic women and their infants, and at €1835.0 and €1407.7 for GDM women and their infants, respectively. Thus, the overall cost per case difference between GDM and normal pregnancies was equal to €817.8 (+ 29.2%), resulting in an economic burden of about €44.8 million in 2014 at national level. Probabilistic sensitivity analysis yielded a cost per case difference ranging between €464.9 and €1164.8 in 80% of simulations.

Conclusions

The economic burden of GDM in Italy is substantial even accounting for short-term medical costs only. Future research also addressing long-term consequences from a broader societal perspective is recommended.