Department of Obstetrics and Gynaecology, Jessop Wing, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield S10 2SF, UK.
Eur J Obstet Gynecol Reprod Biol. 2011 Dec;159(2):329-32. doi: 10.1016/j.ejogrb.2011.09.015. Epub 2011 Oct 2.
To study the outcomes of two-stage GDM screening of morbidly obese women in our obstetric unit and to evaluate the diagnostic performance of 20-week oral glucose tolerance test (OGTT) values in predicting or excluding late onset GDM.
A retrospective study in which 190 pregnant women with BMI ≥40 had two-stage screening: a 75g OGTT is performed at 20 weeks and repeated at 28 weeks if the 20-week OGTT was normal. Receiver operating characteristic (ROC) curves for 20-week OGTT values were constructed in order to obtain an optimal cut-off value of fasting and/or 2-h glucose at 20 weeks from which GDM could be predicted or excluded at 28 weeks. Sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were determined for each of the fasting and 2-h post-load glucose values at 20 weeks.
Forty six (24%) women were diagnosed with GDM. Thirty-two (70%) were diagnosed at 20 weeks and 14 (30%) at 28 weeks. The 2-h cut-off value of ≥6mmol/l at the 20-week OGTT had a negative likelihood ratio of 0.12 to predict GDM at 28 weeks. The low negative likelihood ratio reduces the probability of detecting GDM at 28 weeks from 9% (pre-test probability) to 1% (post-test probability).
Nearly 70% of the women were diagnosed with GDM at 20 weeks, which gives an early opportunity to treat maternal hyperglycaemia with consequent health benefits. A 2-h cut-off glucose value of 6mmol/l at 20 weeks OGTT has a low negative likelihood ratio which virtually excludes GDM at 28 weeks. Hence women with a 2h value of <6mmol/l at 20 weeks can avoid a repeat 28 week OGTT test.
研究我院妇产科肥胖孕妇行两阶段妊娠期糖尿病（GDM）筛查的结局，并评估 20 周口服葡萄糖耐量试验（OGTT）值在预测或排除晚发型 GDM 中的诊断性能。
回顾性研究，190 例 BMI≥40 的孕妇行两阶段筛查：20 周时行 75g OGTT，如果 20 周 OGTT 正常，则在 28 周时重复。为了获得 20 周时空腹和/或 2 小时血糖的最佳截断值，以预测或排除 28 周时的 GDM，构建了 20 周 OGTT 值的受试者工作特征（ROC）曲线。确定了每个 20 周时空腹和负荷后 2 小时血糖值的灵敏度、特异性、阳性似然比和阴性似然比。
46（24%）例孕妇被诊断为 GDM。32（70%）例在 20 周时诊断，14（30%）例在 28 周时诊断。20 周 OGTT 时 2 小时血糖值≥6mmol/L 的截断值预测 28 周 GDM 的阴性似然比为 0.12。低阴性似然比使 28 周时检测到 GDM 的概率从 9%（术前概率）降至 1%（术后概率）。
近 70%的孕妇在 20 周时被诊断为 GDM，这为治疗孕妇高血糖提供了早期机会，从而带来了健康益处。20 周 OGTT 时 2 小时血糖值 6mmol/L 的截断值具有较低的阴性似然比，实际上排除了 28 周时的 GDM。因此，20 周时 2 小时值<6mmol/L 的女性可以避免重复 28 周 OGTT 检查。
