Cut-off value of serum glucose in 1 hour-50 grams glucose challenge test for screening of gestational diabetes in a Bangladeshi population

INTRODUCTION:  Gestational diabetes is now emerging as one of the serious issues in reproductive health which affects health of both the mother and child. To define the cut-off levels of serum glucose during glucose challenge test (GCT), which shows best conformity to the more confirmatory OGTT as per WHO Guideline.

METHODS:  A total of 224 Bangladeshi women who underwent a glucose challenge test (GCT) were prospectively investigated. GCT was performed between 24 to 28 weeks of gestation. Each subject received a 50 grams oral glucose load without regard to the fasting or fed state, followed by determination of 1 hour venous plasma glucose level. Women demonstrating GCT exceeding 130 mg/dl ( >7.2mmol/l) received a 75 grams, 2 hour oral glucose tolerance test to determine whether or not they had gestational diabetes mellitus (GDM).

RESULTS:  Twenty three (10.3%) women were diagnosed to have GDM. The receiver-operator characteristics curve identified a GCT finding above 174 mg/dl as the cut-off value for detecting GDM, which showed sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 35%, 90%, 80% and 68% respectively.

CONCLUSIONS:  Based on PPV and NPV, our data suggest that 1 hour-50 grams GCT is a feasible and acceptable screening test and a cut-off value of 174 mg/dl, as the post-challenge serum glucose, may be appropriate for screening GDM in Bangladeshi population by this test.