Comparison of Accuracy Measures of Two Screening Tests for Gestational Diabetes Mellitus

Abstract

OBJECTIVE -To compare the accuracy measures of the random glucose test and the 50-g glucose challenge test as screening tests for gestational diabetes mellitus (GDM).RESEARCH DESIGN AND METHODS -In this prospective cohort study, pregnant women without preexisting diabetes in two perinatal centers in the Netherlands underwent a random glucose test and a 50-g glucose challenge test between 24 and 28 weeks of gestation. If one of the screening tests exceeded predefined threshold values, the 75-g oral glucose tolerance test (OGTT) was performed within 1 week. Furthermore, the OGTT was performed in a random sample of women in whom both screening tests were normal. GDM was considered present when the OGTT (reference test) exceeded predefined threshold values. Receiver operating characteristic (ROC) analysis was used to evaluate the performance of the two screening tests. The results were corrected for verification bias.RESULTS -We included 1,301 women. The OGTT was performed in 322 women. After correction for verification bias, the random glucose test showed an area under the ROC curve of 0.69 (95% CI 0.61-0.78), whereas the glucose challenge test had an area under the curve of 0.88 (0.83-0.93). There was a significant difference in area under the curve of the two tests of 0.19 (0.11-0.27) in favor of the 50-g glucose challenge test.CONCLUSIONS -In screening for GDM, the 50-g glucose challenge test is more useful than the random glucose test. Diabetes Care 30:2779-2784, 2007G estational diabetes mellitus (GDM) is estimated to occur in 2-9% of all pregnancies (1-5). It is defined as carbohydrate intolerance with onset or first recognition during pregnancy and is associated with increased rates of adverse pregnancy outcomes, such as macrosomia; shoulder dystocia; birth-related trauma, such as fractures and nerve palsies; neonatal hypoglycemia; and jaundice. In addition, women with GDM are at substantially higher risk to develop diabetes in later life (1,6 -8). Results from a randomized controlled trial show that treatment of GDM by means of dietary advice, blood glucose monitoring, and insulin therapy, if required, reduces the rate of serious perinatal complications without increasing the rate of caesarean delivery (1). Based on these results, identification through screening and subsequent treatment of women with GDM appears beneficial. However, consensus on the optimal policy for screening is lacking. The American Diabetes Association recommends screening based on risk factors for GDM (age Ͼ25 years, obese, close relative with diabetes, history of GDM or a previous macrosomic infant, or specific ethnicity) followed by the 50-g 1-h oral glucose challenge test as a screening test (9 -11). Other methods of screening that are regularly used are (repeated) random glucose testing and fasting glucose measurement. It is indefinite which test is the most accurate in testing women for GDM.The diversity in screening methods may result in unidentified cases of GDM and preventable neonatal and maternal morbidity. Establishment of ...

Overweight in Infancy: Which Pre- and Perinatal Factors Determine Overweight Persistence or Reduction A Birth Cohort Followed for 11 Years

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Estimating the risk of gestational diabetes mellitus: a clinical prediction model based on patient characteristics and medical history

“…Details of this procedure have been described elsewhere. 19 The original study was performed in two perinatal centres (Isala Clinics in Zwolle and the University Medical Centre in Utrecht). For the development of the prediction model, we used data from one centre (University Medical Centre in Utrecht).…”

Bayesian Estimation for Performance Measures of Two Diagnostic Tests in the Presence of Verification Bias

“…In the context in which two tests are used against a gold standard under verification bias, Van Leeuwen et al (2007) compared the accuracy measures of the random glucose test and the 50-g glucose challenge test as screening tests for gestational diabetes mellitus, where the 75-g oral glucose tolerance test was used as a reference test. In this study, the reference test was not performed in all patients.…”