Screening for gestational diabetes mellitus in southern Asian women

Gestational diabetes mellitus in Cameroon: prevalence, risk factors and screening strategies

Background

The burden of gestational diabetes (GDM) and the optimal screening strategies in African populations are yet to be determined. We assessed the prevalence of GDM and the performance of various screening tests in a Cameroonian population.

Methods

We carried out a cross-sectional study involving the screening of 983 women at 24-28 weeks of pregnancy for GDM using serial tests, including fasting plasma (FPG), random blood glucose (RBG), a 1-hour 50g glucose challenge test (GCT), and standard 2-hour oral glucose tolerance test (OGTT). GDM was defined using the World Health Organization (WHO 1999), International Association of Diabetes and Pregnancy Special Group (IADPSG 2010), and National Institute for Health Care Excellence (NICE 2015) criteria. GDM correlates were assessed using logistic regressions, and c-statistics were used to assess the performance of screening strategies.

Findings

GDM prevalence was 5·9%, 17·7%, and 11·0% using WHO, IADPSG, and NICE criteria, respectively. Previous stillbirth [odds ratio: 3·14, 95%CI: 1·27-7·76)] was the main correlate of GDM. The optimal cut-points to diagnose WHO-defined GDM were 5·9 mmol/L for RPG (c-statistic 0·62) and 7·1 mmol/L for 1-hour 50g GCT (c-statistic 0·76). The same cut-off value for RPG was applicable for IADPSG-diagnosed GDM while the threshold was 6·5 mmol/L (c-statistic 0·61) for NICE-diagnosed GDM. The optimal cut-off of 1-hour 50g GCT was similar for IADPSG and NICE-diagnosed GDM. WHO-defined GDM was always confirmed by another diagnosis strategy while IADPSG and GCT independently identified at least 66·9 and 41·0% of the cases.

Interpretation

GDM is common among Cameroonian women. Effective detection of GDM in under-resourced settings may require simpler algorithms including the initial use of FPG, which could substantially increase screening yield.

Accuracy of screening tests for gestational diabetes mellitus in Southeast Asia: A systematic review of diagnostic test accuracy studies

BACKGROUND

To investigate the accuracy of screening tests for gestational diabetes mellitus (GDM) in Southeast Asian pregnant women.

METHODS

We searched PubMed (MEDLINE), Web of Science, Cochrane Library, ClinicalTrials.gov, Google Scholar, and Google for relevant articles published in English up to November 2018 using search terms related to GDM, screening tests for GDM and diagnostic performance. The studies were independently screened and selected by both authors. The methodological quality of the included studies was independently assessed by quality assessment of diagnostic accuracy studies 2. A hierarchical summary receiver operating characteristic (HSROC) model was created to estimate the HSROC curve. The summary sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated in a meta-analysis using bivariate random-effects model.

RESULTS

A total of 19 studies were included in which the 100 g oral glucose tolerance test (OGTT) and 75 g OGTT were the two common reference standards for diagnosis of GDM. Most points of diagnostic performance in the HSROC 50 g GCT curve compared with the 100 g OGTT reference standard were clustered in the upper left-hand quadrant. The pooled sensitivity and specificity of the 50 g GCT were 79% (95% confidence interval [CI] 64%-89%) and 74% (95% CI 59%-85%), respectively. For the 75 g OGTT reference standard, the non-fasting 2-hour plasma glucose showed quite similar sensitivity the 50 g GCT compared with the 100 g OGTT reference standard. The pooled sensitivities and specificities of the fasting plasma glucose and hemoglobin A1c were 81% (95% CI 76%-86%) and 70% (95% CI 67%-72%), and 80% (95% CI 66%-90%) and 69% (95% CI 58%-78%), respectively.

CONCLUSION

Our findings indicate that the 50 g GCT using the threshold of 140 mg/dL is a good screening test for identifying GDM at 24 to 28 weeks' gestational age for both high-risk and universal screening strategies in Southeast Asian countries. The non-fasting 2-hour PG, fasting plasma glucose or hemoglobin A1c are alternative choices for screening.

Gestational Diabetes Mellitus Screening and Diagnosis

An ideal screening test for gestational diabetes should be capable of identifying not only women with the disease but also the women with a high risk of developing gestational diabetes mellitus (GDM). Screening and diagnosis are the main steps leading to the way of management. There is a lack of consensus among healthcare professionals regarding the screening methods worldwide. Different study groups advocate a variety of screening methods with the support of evidence-based comprehensive data. Some of the organizations suggest screening for high risk or all pregnant women, while others prefer to offer definitive testing without screening. Glycemic thresholds are also not standardized to decide GDM among different guidelines. Prevalence rates of GDM vary between populations and with the choice of glucose thresholds for both screening and definitive tests. One-step or two-step methods have been used for GDM diagnosis. However, screening includes selecting patients with historical risk factors, 50 g 1-h glucose challenge test, fasting plasma glucose, random plasma glucose, and hemoglobin A1c with different cutoffs. In this chapter, screening and diagnosis methods of GDM accepted by different study groups will be discussed which will be followed by the evaluation of different glycemic thresholds. Then the advantages and disadvantages of used methods will be explained and the chapter will finish with an evaluation of the current international guidelines.

Is Risk Factor-based Screening Good Enough to Detect Gestational Diabetes Mellitus in High-Risk Pregnant Women? A Sri Lankan Experience

Background:

There is a long lasting dilemma over the ideal screening and diagnostic method in gestational diabetes mellitus (GDM). Even though universal screening is commonly practiced, selective screening based on risk factors is also practiced in some center. The aim of this study is to evaluate the most appropriate method to screen GDM in high-risk pregnant women in Sri Lanka.

Methods:

This study was a clinic-based, cross-sectional study conducted in a tertiary referral center, Sri Lanka. All women underwent 75 g oral glucose tolerance test at 24–28 weeks of gestation. Diagnosis of GDM was made according to the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) and World Health Organization (WHO) criteria.

Results:

With universal screening using IADPSG criteria, 23.2% (105/452) were found to have GDM and with risk factor-based screening 20.1% (91/452) were detected to have GDM. The prevalence of GDM dropped to 18.1% when GDM was diagnosed using the WHO criteria with universal screening approach. It was further dropped to 15.7% when the WHO criteria were used along with risk factors-based screening approach.

Conclusions:

The IADPSG criteria labeled considerably higher number of women as having GDM compared to the WHO criteria. With regards to the screening methods, the risk-based screening had a lower detection rate of GDM; however, it reduced the necessity of screening of women by around 20%.

Gestational diabetes mellitus: Screening with fasting plasma glucose

Fasting plasma glucose (FPG) as a screening test for gestational diabetes mellitus (GDM) has had a checkered history. During the last three decades, a few initial anecdotal reports have given way to the recent well-conducted studies. This review: (1) traces the history; (2) weighs the advantages and disadvantages; (3) addresses the significance in early pregnancy; (4) underscores the benefits after delivery; and (5) emphasizes the cost savings of using the FPG in the screening of GDM. It also highlights the utility of fasting capillary glucose and stresses the value of the FPG in circumventing the cumbersome oral glucose tolerance test. An understanding of all the caveats is crucial to be able to use the FPG for investigating glucose intolerance in pregnancy. Thus, all health professionals can use the patient-friendly FPG to simplify the onerous algorithms available for the screening and diagnosis of GDM - thereby helping each and every pregnant woman.

The relationship between post-prandial plasma glucose and post-challenge plasma glucose in Japanese population

The relationship between post-prandial plasma glucose (PPG) and post-challenge plasma glucose (PCG) within individuals was investigated in Japanese population. The oral glucose tolerance test (OGTT) and measurements of PPG 2h after ingestion of a standardized rice-based meal (PPG2h), were performed in 4471 middle-aged Japanese subjects (2774 men and 1697 women, 50.7+/-8.5 years). There was a loose correlation between PPG2h and PCG2h (r=0.327, p<0.001). The diabetes group (n=170) showed the highest PPG2h, followed by the IGT group (n=786) and the NGT group (n=3414) (p<0.05). At the cutoff point of 140 mg/dl (7.8 mmol/l) for PPG2h, specificities were 94.9% for IGT plus diabetes and 92.9% for diabetes, but sensitivities were as low as 23.2% for IGT plus diabetes and 44.7% for diabetes. The correlation of PPG2h with PCG2h was stronger in the obese group (BMI>or=25 kg/m2) than in the lean group (BMI<20 kg/m2). We conclude that the correlation between PPG2h and PCG2h was significant but not very tight. In evaluating PPG2h, if the cutoff point of 140 mg/dl (7.8 mmol/l) for PCG2h is extrapolated, the majority of subjects with dysglycemia could be overlooked.

Fasting plasma glucose as a screening test for gestational diabetes mellitus

Although debated, most preeminent expert panels recommend routine screening for gestational diabetes mellitus (GDM). Among the many tests that have been used and evaluated for the screening of GDM, the fasting plasma glucose (FPG) remains very appealing. It is easy to administer, well tolerated, inexpensive, reproducible and patient friendly. However attractive, the FPG has given varied results in different populations and its use as a screening test for GDM remains uncertain. This review will objectively assess the available studies to find the real value of FPG as a screening test for GDM.