Gestational Diabetes Mellitus (GDM): Relationship Between Higher Cutoff Values for 100 g Oral Glucose Tolerance Test (OGTT) and Insulin Requirement During Pregnancy.

Objectives To study if there is any relationship about higher cutoff values for 100 g oral glucose tolerance test and the need for insulin in women diagnosed with gestational diabetes. Materials and Methods This is a retrospective population-based study of 201 women diagnosed with Gestational Diabetes Mellitus (GDM) between January 2012 and June 2014 in the area of Oviedo, Asturias, Spain. According to diagnostic criteria recommended by GEDE, NDDG, gestational diabetes is diagnosed if two or more plasma glucose levels meet or exceed the following threshold: fasting glucose of 105 mg/dl, 1-h 190 mg/dl, 2-h 165 mg/dl, or 3-h 145 mg/dl. We aim to know if there is any relationship between higher cutoffs and insulin requirement. Results 36 out of 201 patients (17.91%) needed insulin to achieve the targets of blood glucose control. There were no differences in mean maternal age and birthweights. Fasting blood glucose levels were significantly higher in women with further need for insulin than those who only needed diet and exercise (p < 0.001). Also, blood glucose levels 2 h after the oral glucose intake were statistically different between the two groups (p 0.032). AUC for fasting glucose value was the highest according to ROC curve. Conclusions Fasting cutoff vales for 100 g oral glucose tolerance test are consistently higher in women diagnosed with Gestational Diabetes that further needed insulin to achieve adequate blood glucose control. The positive predictive value of fasting glucose value 105 mg/dl on OGTT was 81.1%, whereas for the cut-off 95 mg/dl it was 54.0%.