title: The clinical usefulness of glucose tolerance testing in gestational diabetes to predict early postpartum diabetes mellitus.
abstract: We examined the clinical usefulness of antepartum clinical characteristics, along with measures of glucose tolerance, in Dutch multiethnic women with gestational diabetes mellitus (GDM) for their ability to predict type 2 diabetes within 6 months of delivery (early postpartum diabetes). The present study comprised a cross-sectional 5-year investigation (1998-2003) of a consecutive series of 168 women with GDM identified by a two-stage protocol at 16-33 weeks of gestation. The following data were collected for all women: age and gestational age at entry into the study; prepregnancy body mass index (BMI); ethnicity; obstetric and clinical history, including the onset of early postpartum diabetes; pregnancy outcome; level of fasting C-peptide; and glycemic parameters of 50-g 1-h glucose challenge test and 100-g 3-h oral glucose tolerance test (diagnostic OGTT). We used receiver operating characteristic (ROC) curve analysis to test the clinical usefulness of the glycemic parameters. A total of 11 women (6.5%) developed early postpartum diabetes. Apart from family history of diabetes (p = 0.052), anthropometric, maternal, and neonatal clinical parameters showed no association with early postpartum diabetes in univariate analyses. The level of fasting glucose, and both the glucose challenge test and diagnostic OGTT post-load glucose levels and glucose areas were associated with early postpartum diabetes. ROC curve analysis identifiedall three glucose challenge-test parameters, including fasting glucose concentration, as poor diagnostic tests, with a positive predictive value of approximately 22%, whereas the positive predictive value associated with the area under the diagnostic OGTT curve increased progressively over monitoring time from 20.6% to 100%. Using a 3-h OGTT glucose area threshold of 35.7 mmol.h/L resulted in 100% sensitivity and 100% specificity, identifying the 11 women who developed early postpartum diabetes. In summary, we can conclude from the present analysis that early postpartum diabetes is rare in GDM women (6.5%), and that the clinical usefulness of the total area under the diagnostic 3-h OGTT is superior to all other glycemic parameters for detecting early postpartum diabetes.
authors.affiliation: Department of Clinical Chemistry and Hematology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands. robw01@xs4all.nl
authors.forename: Rob N M
authors.initials: RN
authors.lastname: Weijers
authors.forename: Dik J
authors.initials: DJ
authors.lastname: Bekedam
authors.forename: Henk M J
authors.initials: HM
authors.lastname: Goldschmidt
authors.forename: Yvo M
authors.initials: YM
authors.lastname: Smulders
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D015331:Cohort Studies; D016640:Diabetes, Gestational / Q000097:blood / Q000175:diagnosis*; D005006:Ethnicity; D005260:Female; D005865:Gestational Age; D005951:Glucose Tolerance Test / Q000379:methods*; D006801:Humans; D008875:Middle Aged; D009426:Netherlands; D049590:Postpartum Period / Q000097:blood; D011247:Pregnancy; D012372:ROC Curve; D013997:Time Factors
chemical_list: D001786:Blood Glucose