Alternative method to oral glucose loading test: HbA1c and fructosamine

Diabetes can progress with serious complications during pregnancy. Hence, every women must be screened with oral glucose load test for diabetes during pregnancy and perform OGTT if needed. However, some womens are unable to perform these tests because of sociocultural misbeliefs or their inability to tolerate the test. In this prospective study, we tried to obtain certain plasma HbA1c and fructosamine level for diabetes screening during pregnancy. We compared the healthy group with the GDM group and we found significant difference between the two groups in HbA1c levels, but not for fructosamine levels. For this reason, we focused more on HbA1c levels and BMIs of pregnant womens. 82 healty pregnant, 41 GDM patients who applied to Gazi University Hospital between January 2017 and September 2020 are included in this study. When the cut-off point of HbA1c is 4,85%, we obtain a screening test with 75,6% sensitivity, 58,5% specificity and area under the curve in ROC curve analysis is 0,754. If we apply this test only obese patients (BMI> 30) at OGTT visits, the sensitivity of the screening test increases to 84%, the specificity increases to 61% and the area under the curve in the ROC Curve analysis increases to 0,804. In this study, the number of obese patients during OGTT visits corresponds to 33% of the total patient number. Considering the superiority of oral glucose loading and tolerance tests over the screening test performed with plasma HbA1c value, screening with HbA1c value stands out as a method that should be applied as last option. OGTT still continues to be the standard diagnostic method. Also the oral glucose challenge test is superior to the HbA1c screening test.