Diabetes Care, Vol 21, Issue 8 1246-1249, Copyright © 1998 by American Diabetes Association
Fasting plasma glucose is a useful test for the detection of gestational diabetes. Brazilian Study of Gestational Diabetes (EBDG) Working Group
AJ Reichelt, ER Spichler, L Branchtein, LB Nucci, LJ Franco and MI Schmidt
Hospital de Clinicas de Porto Alegre, Sao Paulo, Brazil. aajacob@netmarket.com.br
OBJECTIVE: To evaluate fasting plasma glucose as a screening test for
states of gestational diabetes. RESEARCH DESIGN AND METHODS: Baseline data
of a cohort conducted in general prenatal care units in Brazil, enrolling
5,579 women aged > or = 20 years with gestational ages of 24-28 weeks at
the time of testing and no previous diagnosis of diabetes. A standardized
2-h 75-g oral glucose tolerance test was performed in 5,010 women.
Gestational diabetes and its subcategories--diabetes and impaired glucose
tolerance--were defined according to the 1994 World Health Organization
panel recommendations. We evaluated screening properties of calculated
sensitivity and specificity for fasting plasma glucose with receiver
operator characteristic curves. RESULTS: For detection of the subcategory
diabetes, a fasting plasma glucose of 89 mg/dl jointly maximizes
sensitivity (88%) and specificity (78%), identifying 22% of the women as
test-positive. For detection of impaired glucose tolerance, a value of 85
mg/dl jointly maximizes sensitivity and specificity (68%), identifying as
test-positive 35% of the women. Lowering the cut point to 81 mg/dl
increases sensitivity to 81%, but decreases specificity to 54%, labeling as
test-positive 49% of the women. CONCLUSIONS: Fasting plasma glucose is a
useful test for the screening of both subcategories of gestational
diabetes, a threshold of 85 mg/dl being an acceptable option. Effective
screening for the subcategory diabetes can be achieved using a cut point of
89 mg/dl. If greater emphasis is placed on the detection of impaired
glucose tolerance, a lower value, 81 mg/dl, may be needed.