A 2 hour versus the 3 hour 100 g glucose tolerance test for diagnosing gestational diabetes mellitus

AIM: To determine how the omission of the third hour glucose measurement of the 100 g oral glucose tolerance test (GTT) affects the diagnosis of gestational diabetes mellitus (GDM). METHODS: Retrospective chart review of 876 women delivered in a tertiary care hospital in Israel during a three-year period, who underwent a 100 g 3 hour oral GTT following an abnormal 50 g glucose screen. GDM was diagnosed according to the "criterion standard" accepted in the Fourth International Workshop Conference on GDM. The results of the 100 g 3 hour oral GTT were then retrospectively re-evaluated by omission of the third hour plasma glucose measurement from the "criterion standard". RESULTS: GDM was diagnosed in 28.4% of the study. patients, while the omission of the third hour glucose measurement resulted in a 26.4% diagnosis of GDM. The perinatal data of the 18-omitted cases suggests that their exclusion from the GDM group would not have altered substantially the perinatal outcome of the study cohort. CONCLUSIONS: A 100 g 2 hour oral GTT is a simple and economic alternative to the 100 g 3 hour oral GTT.     

口服葡萄糖耐量试验中空腹血糖水平在妊娠期糖尿病诊断中的作用

目的 探讨妊娠24～28周间口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)中空腹血糖值在诊断妊娠期糖尿病(gestational diabetes mellitus,GDM)中的作用. 方法 对2010年1月1日至12月31日间,于首都医科大学附属北京妇产医院产前检查,妊娠早期空腹血糖正常(＜7.0 mmol/L),妊娠24～28周50 g葡萄糖负荷试验≥7.8 mmol/L并行75 g OGTT的6516例孕妇的OGTT结果进行分组分析.采用卡方检验,了解按OGTT空腹血糖水平分组后GDM的诊断情况. 结果 按国际糖尿病与妊娠研究组(International Association of Diabetes and Pregnancy Study Groups,IADPSG)的GDM诊断标准,单纯依据OGTT空腹血糖升高(≥5.1 mmol/L)可诊断15.0％(980/6516)的GDM患者,剔除这部分患者后,余OGTT空腹血糖＜5.1 mmol/L的5536例孕妇纳入分组分析.以OGTT中空腹血糖值每升高0.1 mmol/L为1个分界进行第1次分组,结果显示,随着空腹血糖水平的升高,GDM的诊断率逐渐增加(X2=282.175,P=0.000).按照空腹血糖在4.0～4.8 mmol/L间每升高0.2 mmol/L为1个分界进行第2次分组分析,显示随着空腹血糖水平的升高,各组GDM诊断率仍呈现升高趋势(X2=274.364,P=0.000).两种分组结果均显示,当OGTT中空腹血糖水平＜4.2 mmol/L(1226/5536,占22.1％)时,GDM诊断率为3.6％(44/1226),可以考虑对该部分患者暂时不行OGTT检测;当OGTT中空腹血糖水平≥4.8 mmol/L时,GDM诊断率明显增加,为26.2％(298/1138),故应提高警惕. 结论 妊娠24～28周行OGTT前建议先行空腹血糖筛查,空腹血糖≤4.2 mmol/L的低危孕妇可免于OGTT检测.     

妊娠糖代谢异常孕妇葡萄糖耐量试验结果评价

目的　分析妊娠期糖代谢异常孕妇口服葡萄糖耐量试验 (oralglucosetolerancetest ,OGTT)的特点 ,探讨OGTT 3h血糖检测 ,在妊娠糖尿病 (gestationaldiabetesmellitus ,GDM)和妊娠糖耐量受损 (gestationalimpairedglucosetest ,GIGT)诊断中的价值。　 方法　回顾性收集、分析我院1989年 1月至 2 0 0 2年 12月 6 4 7例GDM和 2 0 0 0年 1月至 2 0 0 2年 12月 2 33例GIGT孕妇的OGTT血糖特点 ,以及各点血糖在糖代谢异常孕妇中的诊断价值。　结果　 (1) 6 4 7例GDM孕妇中 ,112例因空腹血糖明显异常被确诊为GDM ;5 35例进行了OGTT ,4 9.2 % (2 6 3/5 35 )的孕妇空腹血糖异常 ;90 .1% (482 /5 35 )的孕妇 1h血糖异常 ;6 4 .7% (35 9/ 5 35 )的孕妇 2h血糖异常 ;仅 2 1.3% (114 / 5 35 )的孕妇 3h血糖达到异常 ,其中 ,4 9.1% (5 6 / 114 )伴有OGTT其它三项血糖异常 ,34.2 % (39/114 )伴有OGTT另外两项异常 ,19例伴有另外一项异常 ,即省略OGTT 3h血糖检测 ,2 .9% (19/6 4 7)的GDM被漏诊为GIGT。 (2 ) 2 33例GIGT中 ,只有 1.72 % (4/2 33)依靠OGTT 3h血糖异常得出诊断。(3)GDM孕妇空腹血糖达异常 (≥ 5 .8mmol/L)时 ,5 9.7%需要胰岛素治疗 ,高于空腹血糖 <5 .8mmol/L需要胰岛素治疗者 (41.6 % ) ,P <0 .0 1;5 0g葡萄     

Effect of fetal hyperinsulinism on oral glucose tolerance test results in patients with gestational diabetes mellitus

OBJECTIVE: This study was undertaken to evaluate the impact of the fetoplacental glucose steal phenomenon on the results of oral glucose tolerance testing in pregnancies complicated by gestational diabetes mellitus with fetal hyperinsulinism. STUDY DESIGN: This was an analysis of the cases of 34 patients with two consecutive abnormal oral glucose tolerance test results and amniotic fluid insulin measurement before institution of insulin therapy. Patients were divided into groups on the basis of normal versus elevated amniotic fluid insulin concentrations. RESULTS: Oral glucose tolerance tests were done at a mean (+/-SD) of 24.9 +/- 5.7 and 30.7 +/- 3.2 weeks' gestation, and amniotic fluid insulin measurements were done at 31.1 +/- 3.2 weeks' gestation. In 13 women with gestational diabetes mellitus with normal amniotic fluid insulin concentration, maternal postload blood glucose levels at 1 hour increased by 12 mg/dL (168 vs 180 mg/dL; 9.3 vs 10.0 mmol/L; P = .0006) during the course of 6 weeks. In contrast, in 21 women with gestational diabetes mellitus with elevated amniotic fluid insulin levels (>7 microU/mL; >42 pmol/L), 1-hour postload blood glucose levels decreased by 22 mg/dL (201 vs 179 mg/dL; 11.2 vs 9.9 mmol/L; P = .002) during the same period. The higher the amniotic fluid insulin level, the larger the decrease (R = 0.504; P =.02). Although low amniotic fluid insulin levels were correlated significantly with 1-hour glucose levels of the first and second oral glucose tolerance tests, high insulin levels were no longer correlated with the second oral glucose tolerance test. CONCLUSION: Exaggerated fetal glucose siphoning may provide misleading oral glucose tolerance test results in pregnancies complicated by fetal hyperinsulinism by blunting maternal postload glucose peaks. Consequently, oral glucose tolerance test results in a pregnancy complicated by gestational diabetes mellitus with a fetus that already has hyperinsulinemia may erroneously be considered normal.     

对8 665例孕妇行妊娠期糖尿病筛查的临床研究

目的探讨50 g葡萄糖负荷试验 (GCT) 筛查妊娠期糖尿病( GDM) 的阈值、适宜孕周,孕妇年龄和体重因素对GDM发生的影响.方法采用回顾性研究的方法,对1995年1月至2001年3月在北京大学第一医院妇产科行GCT的8 665例孕妇的临床资料进行分析.结果 (1)8 665例孕妇 GCT 1 h平均血糖水平为(6.8±1.7) mmol/L,以7.8 mmol/L为切点,GCT异常率为25.2%,GDM漏诊率为5.3%(17/321);以7.2 mmol/L为切点,GCT异常率为36.5%,GDM漏诊率为2.8 %(9/321);以8.3 mmol/L为切点,GDM漏诊率为15.9%(51/321). (2)GCT 1 h血糖≥11.2 mmol/L者中,GDM发生率为55.8%(92/165),其中62.0%(57/92)根据空腹血糖水平可以做出诊断.(3)孕24周以后,不同孕周间GCT异常率无差异.(4)GCT异常率和GDM发生率不同年龄组比较,差异有极显著性(P<0.01),25岁以下无GDM高危因素的孕妇GDM发生率为0.3%,显著低于年龄≥25岁的孕妇.(5)孕26～28周时孕妇的平均体重指数(BMI)为(24.9±2.9) kg/m2(±s),当BMI≥27.8时,GCT异常率和GDM发生率均显著增高.结论 (1)GCT筛查GDM以7.8 mmol/L为切点是合理的; GCT 1 h血糖≥11.2 mmol/L 时,应先行空腹血糖检查确诊是否为GDM.(2)孕24周后尽早行GCT是恰当的,但对于有明显高危因素者应在孕24周前行GCT.(3)孕妇年龄和体重与GDM的发生密切相关,25岁以下无高危因素者可以不行GDM筛查.     

Occurrence of gestational diabetes mellitus and the value of different screening indicators for the oral glucose tolerance test

BACKGROUND: The objective of the present study was to determine prevalence of gestational diabetes mellitus (GDM) in terms of impaired glucose tolerance (IGT) and diabetes mellitus (DM), and the value of traditional anamnestic risk factors for predicting outcome of the oral glucose tolerance test (OGTT). METHODS: A prospective population-based study in a defined geographic area in Sweden. All pregnant nondiabetic women (n = 4918) attending maternal health care from July 1994 to June 1996 were offered a 75g OGTT in gestational weeks 28-32. Traditional anamnestic risk factors, as well as results of the OGTT in terms of fasting-B-glucose and 2h-B-glucose, were registered. RESULTS: 3616 (73.5%) women agreed to perform the OGTT. Sixty-one (1.7%) of those had GDM [47 (1.3%) had impaired glucose tolerance and 14 (0.4%) had diabetes mellitus]. 15.8% fulfilled traditional risk factor criteria. Traditional anamnestic risk factors as an indicator to perform an OGTT identified 29/61 GDM women and 9/14 women with DM. Among primiparas, 4/21 with gestational diabetes mellitus were detected. CONCLUSION: Using traditional risk factors as an indicator to perform an OGTT gives a low sensitivity to detect GDM and even DM especially among primiparas.     

Use of oral glucose tolerance test in early pregnancy to predict late-onset gestational diabetes mellitus in high-risk women

AIM: To evaluate if any single plasma glucose level from the four values of the normal 100-g oral glucose tolerance test (OGTT) in early pregnancy (< or =20 weeks of gestation) could predict gestational diabetes mellitus (GDM) diagnosed from a second OGTT in late pregnancy (28-32 weeks). METHODS: Glucose levels of pregnant women at high-risk for GDM, who had had a normal early OGTT, and who underwent the second test in late pregnancy, were studied. Each of the four plasma glucose values of the early OGTT was determined for sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The receiver operating characteristic curves of these four OGTT values were then constructed to find the optimal value to predict late-onset GDM. RESULTS: Of 193 pregnant women who had had a normal early OGTT, 154 also had a normal OGTT in late pregnancy while 39 had an abnormal test and were diagnosed with GDM. Among the four glucose values of the early OGTT, the 1-h value yielded the best diagnostic performance to predict late-onset GDM. The sensitivity, specificity, PPV, NPV, and area under the curve achieved from its optimal cutoff level of > or =155 mg/dL (8.6 mmol/L) were 89.7%, 64.3%, 38.9%, 96.1%, and 0.77, respectively. CONCLUSIONS: A 1-h glucose value > or =155 mg/dL at the early OGTT yielded the best diagnostic performance. However, the low specificity and PPV rendered it suboptimal to predict late-onset GDM. Nevertheless, a considerable number of high-risk women could avoid the second OGTT in late pregnancy due to its high sensitivity and NPV.     

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.     

Fasting capillary glucose as a screening test for gestational diabetes mellitus

Objective  To evaluate fasting capillary glucose as a screening test for gestational diabetes mellitus (GDM) compared with traditional risk factors and repeated random capillary glucose measurements.
Design  Cross-sectional, population-based study.
Setting  Maternal Health Care Clinics in Örebro County, Sweden.
Population  An unselected population of women without diabetes.
Methods  Fasting capillary glucose levels were measured at gestational weeks 28–32. Random capillary glucose levels were measured four to six times during pregnancy. Traditional risk factors for GDM were registered. GDM was diagnosed using a 75-g oral glucose tolerance test.
Main outcome measures  Sensitivity, specificity, likelihood ratios.
Results  In 55 of 3616 women participating in the study, GDM was diagnosed before 34 weeks of gestation. For fasting capillary glucose cutoff values between 4.0 and 5.0 mmol/l, sensitivity was in the range between 87 and 47% and specificity between 51 and 96%. Using a combined screening model of traditional risk factors with fasting capillary glucose at various cutoff values increased the sensitivity only slightly compared with using fasting capillary glucose alone.
Conclusion  In this Swedish, unselected, low-risk population, fasting capillary glucose measurements were found to be an acceptable and useful screening test for GDM.     

Risk factors for gestational diabetes mellitus and results of glucose tolerance tests

The authors made an effort to verify the connection between the presence of risk factors for GDM and results of screening and diagnostic tests. Study group consisted 302 patients. Gestational diabetes was more frequently diagnosed when an excessive maternal weight and family history of diabetes occurred. Among women with gestational diabetes recognised on the basis of the tests results (screening or diagnostic), 1/3 of patients had no evidence of any risk factor. There is no correlation between the number of risk factors and the occurrence of gestational diabetes. The risk factors were present in half of the investigated patients.     

Effect of advancing pregnancy on the glucose tolerance test and on the 50-g oral glucose load screening test for gestational diabetes

To determine the validity of the 50-g, one-hour glucose screening test for gestational diabetes in relation to the duration of pregnancy, 101 patients from a high-risk population had the screening test in the first trimester and glucose tolerance tests (GTT) in the second and third trimesters. The sensitivity (88%) and specificity (82%) of the screening test were similar to values reported when the test is performed later in pregnancy. However, immediate follow-up GTTs in the second trimester revealed only 25% instead of 88% of the gestational diabetic patients uncovered by the positive screening tests. Guidelines for screening for gestational diabetes should include follow-up with a third-trimester GTT on all patients who have positive screening tests even in the presence of normal follow-up second trimester GTTs.     

孕期口服葡萄糖耐量试验结果中血糖水平较低者的围产儿结局

目的 探讨孕期口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)结果中血糖水平偏低孕妇的围产儿结局特点.方法 统计OGTT结果了解空腹、服糖后1 h、2 h、3 h的血糖百分位数分布.血糖水平小于第5百分位者为血糖水平较低组,小于第1百分位者为血糖水平极低组,比较血糖水平较低组、血糖水平极低组和血糖水平不低组孕妇的围产儿结局. 结果 空腹血糖水平与新生儿体重和身长分别呈正相关(r=0.16,P＜0.01;r=0.081,P＜0.05).空腹血糖极低组孕妇分娩的新生儿平均出生体重明显低于其余孕妇[(2817±764)g和(3439±487)g,t=3.344,P＜0.01];其小于胎龄儿分娩率亦高于血糖水平不低组(3/7和3.4%,y2=22.78,P＜0.01);其出生体重＜3000 g的新生儿分娩率明显高于其余孕妇(5/7和14.73%,P＜0.01).服糖后2h血糖水平较低组孕妇分娩的新生儿平均出生身长(49.03±1.68)cm,显著低于血糖值不低组(49.48±1.65cm,P＜0.05). 结论 OGTT结果 中血糖水平偏低的孕妇分娩的新生儿体重低、身长短、小于胎龄儿分娩率高.     

Family history of diabetes mellitus and oral glucose tolerance testing criteria

A review of 185 obstetrical patients, having a family history of diabetes mellitus without medical history of glucose intolerance in the non-pregnant state was conducted. A 3-hour 100-g oral glucose tolerance test was performed on all patients between 20 and 34 weeks of gestation. According to O'Sullivan's criteria for glucose tolerance testing, normal glucose tolerance occurred in 89.7%, while Class A diabetes was identified in 10.3% of patients tested. 3.8% of the study population fulfilled the O'Sullivan criteria for abnormal glucose intolerance and required insulin treatment during pregnancy. The Division of Perinatal Medicine at Duke University has traditionally defined the abnormal glucose tolerance test at glucose values lower than O'Sullivan's internationally accepted criteria. An intermediate group, having abnormal glucose values according to the Duke criteria, was classified as "Carbohydrate Intolerance", comprised 32.4% of the patients tested and were managed identically to O'Sullivan Class A Diabetes. Analysis or perinatal outcome, including macrosomia, birth trauma and neonatal morbidity, revealed that Carbohydrate Intolerance patients fulfilling O'Sullivan criteria, being similar to patients with 'normal' GTT test results. Patients having a family history of diabetes mellitus, appeared as a group to be at increased risk for macrosomia, fetal distress and cesarean delivery, compared with the general population.     

孕妇血清瘦素水平测定对妊娠期糖耐量异常的预测价值

目的　探讨孕妇血清瘦素水平测定对妊娠期糖耐量异常有无预测价值。方法　采用葡萄糖负荷试验法对 583例孕妇行妊娠期糖尿病筛查,根据筛查结果分为糖耐量正常组及糖耐量异常组(包括妊娠期糖耐量低减和妊娠期糖尿病)孕妇。同时检测两组孕妇不同孕周的血清瘦素水平。结果　(1)糖耐量正常组 507例孕妇血清瘦素水平由孕 24周的 (7.0±1.8)μg/L逐渐缓慢上升,至孕 34~35周时上升最为明显,形成峰值为(9.4±2.1)μg/L,之后略有下降。(2)糖耐量异常组 76例(妊娠期糖耐量低减 61例、妊娠期糖尿病 15例 )孕妇血清瘦素水平波动在 ( 11.3±3.1 )μg/L至(14.5±4.3)μg/L之间,不同孕周间的血清瘦素水平比较,差异无统计学意义 (P>0.05)。(3)糖耐量异常组孕妇平均血清瘦素水平为(12.5±3.5)μg/L,显著高于糖耐量正常组的 (8.5±2.6 )μg/L,且在任何孕周,糖耐量异常组孕妇血清瘦素水平均比糖耐量正常组显著升高,两组比较,差异有统计学意义(P<0.05)。(4) 15例妊娠期糖尿病孕妇中,有 10例血清瘦素水平超过 14.0μg/L。当瘦素水平≥17.0μg/L时, 64.7%的孕妇有不同程度的糖耐量异常。瘦素水平与妊娠期糖耐量低减和妊娠期糖尿病的患病率呈正相关。结论　血清瘦素水平与妊娠期糖耐量异常有相关性, 血清瘦素水平升高对妊娠期     

Accuracy of the random glucose test as screening test for gestational diabetes mellitus: a systematic review

Objective

Although not formally supported by guidelines, random glucose testing (RGT) is frequently used to screen for gestational diabetes mellitus (GDM). Results on test accuracy are inconclusive. The aim of this study was to systematically review the literature and calculate summary estimates of accuracy measures of RGT as screening test for GDM.

Study design

Systematic review to identify studies comparing RGT to oral glucose tolerance testing before 32 weeks of pregnancy. A systematic search without language restrictions was performed in MEDLINE (1950 till April 2008) and EMBASE (1980 to April 2008). Study selection and data extraction were performed by two independent reviewers. Outcome measures were summary estimates of test accuracy of RGT.

Results

Six studies were included, reporting on 3537 women. Due to the small number of studies and heterogeneity, no summary estimates of test accuracy were calculated. Reported sensitivities and specificities of individual studies varied. For 100% sensitivity, specificity was around 40%. For sensitivity of 60% specificity was at most 80%. When specificity approached 100%, sensitivity dropped to 20-30%.

Conclusion

Available evidence on the accuracy of RGT to test for GDM is limited. Based on studies in our systematic review, we consider single random glucose measurement inadequate to screen for GDM.