Screening for Gestational Diabetes Mellitus by Measuring Glycated Hemoglobin Can Reduce the Use of the Glucose Challenge Test

Abstract

Background: Physiological changes during pregnancy, such as dilutional anemia and a reduced half-life of red blood cells, have prevented the use of glycated Hb (HbA1c) as a biomarker for gestational diabetes mellitus (GDM). Nevertheless, increasing evidence supports the use of HbA1c in GDM diagnostic strategies.We studied HbA1c as a biomarker of GDM and its possible use as a screening test to avoid the use of the glucose challenge test (GCT).Methods: This case-control study involved 607 pregnant women between the 24th and 28th week of gestation. HbA1c level was determined, and GDM was diagnosed according to the National Diabetes Data Group criteria. The area under the ROC curve (AUC) was determined; two low and two high cut-off points were established to rule out GDM and classify high-risk pregnant women, respectively. For each cut-off, sensitivity (S), specificity (SP), and total number and percentage of GCTs avoided were determined. Results:The AUC for HbA1c diagnostic performance was 0.68 (95% confidence interval 0.57-0.79). Using 4.6% HbA1c (27 mmol/mol) as the lower cut-off (S = 100%), 14% of participants could avoid the GCT. Using 5.5% HbA1c (36 mmol/mol) as the upper cut-off (SP = 94.5%), 6% of participants would be considered at high risk.Conclusions: HbA1c can be used as a screening test prior to the GCT, thereby reducing the need for the GCT among pregnant women at a low risk of GDM.

Reliability of glycosylated hemoglobin in the diagnosis of gestational diabetes mellitus

“…The current study has shown a poor reliability of HbA1c for the diagnosis of GDM (AUC = 0.62). This finding was similar to the previous studies findings 10,16‐19 which reported that HbA1c values cannot replace OGTT for the diagnosis of GDM. On the other hand, several previous studies have shown a high efficiency with a good/excellent reliability of HbA1c for the diagnosis of GDM in which the AUC values ranged from 0.805 to 0.937 12,14,21 .…”

“…Recent studies have reported various levels of reliability/accuracy of HbA1c in diagnosing GDM. While some studies have shown a poor reliability, 10,16‐18 others have shown a good or excellent reliability of HbA1c in diagnosing GDM 12,14,19‐21 …”

An update on gestational hyperglycemia diagnosis during the COVID-19 pandemic

“…In a meta-analysis of studies using different diagnostic criteria for GD, HbA1c ≥ 5.7% had a mean sensitivity of 24.7% and a specificity of 95.5% for the diagnosis of GD 17 . With regard to the NDDG criteria, Maesa et al reported a sensitivity of 25.9% for a cut-off point of ≥ 5.5% 18 . This is why guides such as the Canadian guide propose a combined strategy of HbA1c and random glycemia, while the Royal College of Obstetricians and Gynaecologists propose HbA1c and basal glycemia or random glycemia 2 .…”

Actualización urgente: alternativa temporal para el diagnóstico de hiper-glucemia gestacional y el seguimiento de estas mujeres y aquellas con diabetes pregestacional durante la pandemia COVID-19. Consenso del Grupo Español de Diabetes y Embarazo (GEDE) de la Sociedad Española de Diabetes (SED) y la Sociedad Española de Ginecología y Obstetricia (SEGO)

“…En un metaanálisis en estudios que utilizaban diferentes criterios diagnósticos de DG, una HbA1c ≥ 5,7% tenía una sensibilidad promedio del 24,7% y una especificidad del 95,5% para el diagnóstico de DG 17 . En relación con criterios NDDG, Maesa et al refieren una sensibilidad del 25,9% para un punto de corte ≥ 5,5% 18 . Por esto guías como la canadiense proponen una estrategia combinada de HbA1c y glucemia al azar y el Royal College of Obstetricians and Gynaecologists de HbA1c y glucemia basal o al azar 2 .…”