CORRESPONDENCE BETWEEN FIRST TRIMESTER FASTING GLICEMIA AND ORAL GLUCOSE TOLERANCE TEST IN GESTATIONAL DIABETES DIAGNOSIS

Abstract Aim: to evaluate the correspondence between first trimester fasting glycemia and the results of the oral glucose tolerance test (OGTT) in diagnosing gestational diabetes (GDM). Methods: medical records of all consecutive women who had a diagnostic OGTT according the IADPSG in the last year have retrospectively reviewed. First trimester glucose fasting value ≥ 92 mg/dl recommended as diagnostic too was verified then for each patients of this cohort. Moreover a ROC curve and a multiple logistic regression models were constructed to calculate the predictive capability of this cut-off in diagnosing GDM. Results: in our population of 738 eligible pregnant women a prevalence of 11.9% of GDM was revealed by OGTT. Then when we retrospectively considered the first trimester glucose fasting value for each patient we had 29 more patients who should be diagnosed because a glycemia ≥ 92 mg/dl but without a confirmatory OGTT. If we don’t consider diagnostic but only predictive the value for fasting we have an AUC of 0.614 (95% CI ) and an aOR of 14 ( 95% CI ) in this group respect the reference group (< 75 mg/dl). Conclusions: there is no complete correspondence in diagnosing GDM between the first trimester glucose fasting value and the results of the 2h – 75 g OGTT performed at the early of the third trimester. However, although no diagnostic, the fasting value ≥ 92 mg/dl may be considered a risk factor for GDM with an high predictive capability.