BackgroundThe best strategy to identify women with gestational diabetes mellitus (GDM) is unclear.Objectives To perform a systematic review to calculate summary estimates of the sensitivity and specificity of the 50-g glucose challenge test for GDM.Search strategy Systematic search of MEDLINE, EMBASE and Web of Science.Selection criteria Articles that compared the 50-g glucose challenge test with the oral glucose tolerance test (OGTT, with a 75-or 100-g reference standard) before 32 weeks of gestation.Data collection and analysis Summary estimates of sensitivity and specificity, with 95% confidence intervals and summary receiver operating characteristic curves, were calculated using bivariate random-effects models. Two reviewers independently selected articles that compared the 50 g glucose challenge test to the oral glucose tolerance test (OGTT, 75 or 100 gram, reference standard) before 32 weeks of gestation.Main results Twenty-six studies were included (13 564 women). Studies that included women with risk factors showed a pooled sensitivity of the 50-g glucose challenge test of 0.74 (95% CI 0.62-0.87), a pooled specificity of 0.77 (95% CI 0.66-0.89) (threshold value of 7.8 mmol/l), a derived positive likelihood ratio (LR) of 3.2 (95% CI 2.0-5.2) and a negative LR of 0.34 (95% CI 0.22-0.53). In studies with consecutive recruitment, the pooled sensitivity was 0.74 (95% CI 0.62-0.87) for a specificity of 0.85 (95% CI 0.80-0.91), with a derived positive LR of 4.9 (95% CI 3.5-7.0) and negative LR of 0.31 (95% CI 0.20-0.47). Increasing the threshold for disease (OGTT result) increased the sensitivity of the challenge test, and decreased the specificity.Author's conclusions The 50-g glucose challenge test is acceptable to screen for GDM, but cannot replace the OGTT. Further possibilities of combining the 50-g glucose challenge test with other screening strategies should be explored.

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 ...

Glucose challenge test for detecting gestational diabetes mellitus: a systematic review Sir, The sensitivity and specificity of screening tests are crucial to adequately detect, and thus efficiently prevent and treat, gestational diabetes mellitus (GDM). The fascinating report by van Leeuwen et al. 1 was a meta-analysis on the 50-g glucose challenge test (GCT), spanning 26 papers. The oral glucose tolerance test (OGTT), following the ingestion of 75 or 100 g of glucose, was used as the reference/diagnostic test for the meta-analysis, which found similar results among studies including women with risk factors and studies with consecutive recruitment: a pooled sensitivity of 0.74 and 0.74, and a pooled specificity of 0.77 and 0.85, respectively. Interestingly, GCT displayed only modest accuracy for GDM screening, with a positive likelihood ratio (LR) of 3.2 and 4.9, and negative LR of 0.34 and 0.32, respectively. As expected, a higher threshold for a positive OGTT increased the sensitivity and decreased the specificity of the GCT.Despite its relatively weak sensitivity and specificity values, the authors concluded that GCT is nevertheless acceptable for screening, but can't replace the OGTT. This conclusion is in agreement with the recent guidelines of the International Association of Diabetes and Pregnancy Study Groups (IADPSG) and the American Diabetes Association (ADA). Both associations recommend OGTT as a one-step screening and diagnosis combination. This limits the scope of the meta-analysis reported by van Leeuwen et al., but the degree of adherence to IADPSG/ADA guidelines has yet to be established.Other limitations are linked to the inherent drawbacks of GCT and OGTT, relating mainly to the length of time required to process blood samples in order to measure blood glucose (BG), as well as the actual time of day when women are tested. It is widely recognised that the nature of a sample (serum/plasma), its storage temperature, the time elapsed between sampling and centrifugation (in-tube glycolysis), and the use of a glycolysis inhibitor are all factors that can alter BG values. The impact of these factors was recently addressed in a study of 60 pregnant women. When tubes were processed systematically and centrifugation performed 5 minutes after blood collection, plasma BG values increased by 10 mg/l, uncovering fifteen cases of diabetes that were previously overlooked when the regular routine was used. 2Another key issue for screening accuracy is linked to the actual time of day when testing is performed. The literature supports a circadian variation of BG in pregnant women, with higher values for GCT and OGTT performed in the afternoon, observed in studies performed in relatively small cohorts.3,4 These all but forgotten results suggested that GCT cut-off values should be adjusted for morning versus afternoon testing. Unfortunately, no further recommendation has ever been issued regarding the best time of day for testing.The bottom line is that GDM may all too often be overlooked for reasons easily circu...

OA&CHX and COMBI-group showed a clinically relevant improvement after the treatment phase in terms of dental plaque and gingival bleeding levels. At the 4-month clinical assessment, there was no longer a significant difference between groups.