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Title: An evaluation of the screening approaches for gestational diabetes mellitus
Author: Fang, Qing
ISNI:       0000 0004 6348 7186
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2016
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Background: Gestational diabetes mellitus (GDM) is defined as any degree of glucose intolerance that occurs or is first recognised during pregnancy. The prevalence of GDM is 1-28% globally and 11% in China. Although GDM can cause severe maternal and neonatal outcomes, there is no consensus worldwide as to whether universal or selective screening of expectant mothers should be recommended. In 2010, The International Association of Diabetes and Pregnancy Study Groups (IADPSG) recommended that all pregnant women should be screened via a one-step universal screening approach for GDM, using a 75g oral glucose tolerance test (OGTT) with reduced thresholds. Despite ongoing debate over the efficacy and use of the IADPSG approach, China was the first country to adopt the new screening approach. A number of observational studies have shown that the new IADSPG approach is clinically more effective. However, reservations exist as to the associated increase in health costs and inconvenience to pregnant women. Aim: To assess and explore the best screening approach for GDM both globally and in China. Methods: The research involved three projects. Project I (Chapter 3) was a systematic review of the effectiveness and cost-effectiveness of universal versus selective screening for GDM, which followed a standard systematic review procedure for Diagnostic Test Accuracy studies. Project II (Chapter 4) was a Q methodology study to investigate the pregnant women’s attitudes towards and experience of the IADPSG one-step screening approach for GDM in China. A total of 30 pregnant women who visited the hospital for antenatal care in 2014 were recruited to participate in the study. The Q methodology study was undertaken using the FlashQ software and were analysed using the PQMethod software. Project III (Chapter 5) was a case-control study to establish and assess a risk score algorithm in order to improve the IADPSG approach for GDM screening in China. Medical records of 550 pregnant women (272 GDM cases and 278 controls) who had given birth in the year 2013 at the Chengdu First People’s Hospital were retrospectively collected and analysed. Univariable analysis and multiple logistic regression analysis were used to identify GDM risk factors and to formulate the risk score algorithm. A Receiver Operating Characteristic (ROC) curve was employed to assess the effectiveness of the risk score algorithm for GDM screening. Results: The systematic review (Chapter 3) included 28 effectiveness studies, four cost studies and one cost-effectiveness study. Seven out of the 28 effectiveness studies and the cost-effectiveness study favoured selective screening. The Q methodology study (Chapter 4) suggested that the participants agreed as to the importance and necessity of the IADPSG one-step GDM screening for all pregnant women. However, the non-GDM women felt somewhat burdened in undertaking the fasting and 2-hour oral Glucose Tolerance Test (OGTT) for GDM under the IADPSG approach. The participants also desired more information on GDM and OGTT both before and after the test. The case-control study (Chapter 5) identified age, height, body mass index (BMI), family history of diabetes, waist circumference, previous deliveries and blood pressure before 24th week of gestation to be risk factors for GDM in the Chinese population. Subsequently, a risk score algorithm was established, whereby the use of the risk score to select high-risk women for screening could help to exclude nearly half (45%) of non-GDM women from the OGTT while still diagnosing 80% of the GDM cases. Conclusion: Universal screening for GDM is recommended for areas where GDM prevalence is relatively high and where economic constraints circumscribing implementation of the approach do not exist. For areas where GDM prevalence is low, it is recommended that current practice, whether it is universal or selective screening, should be retained until more robust evidence emerges. The IADPSG one-step universal screening was viewed positively in terms of importance and necessity by participants of the study, and they felt that GDM screening is necessary to be undergone by every pregnant woman. At the same time, the non-GDM women also felt strongly that the two-hour OGTT requiring 3 blood samples over the test period was inconvenient and burdensome. Alternatively, the use of a risk score-based selective IADPSG approach was observed to be conducive to the exemption of nearly half (45%) of non-GDM women from the OGTT test while still diagnosing 80% of the GDM cases in China. A future validation cohort from other parts of China is required to affirm the effectiveness of this risk scoring algorithm.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: RG Gynecology and obstetrics