Mid‐trimester glycosylated hemoglobin levels (HbA1c) and its correlation with oral glucose tolerance test (World Health Organization 1999)

Abstract

Aim The aim of the present study was to assess the role of hemoglobin A1c (HbA1c) in screening of gestational diabetes mellitus (GDM) and to compare its efficacy with 75 g oral glucose tolerance test (OGTT) (World Health Organization [WHO]) screening criteria. Methods A prospective observational study was performed on a total of 260 women attending antenatal outpatient department of our hospital at 24–28 weeks of gestation. All women underwent 75‐g OGTT testing, and WHO 1999 criteria was used for diagnosis of GDM. Also, a HbA1c test was performed for the same women. Results Prevalence of GDM was found to be 19.6% by OGTT. Mean HbA1c values in GDM was significantly higher than non‐GDM. HbA1c correlated well with both fasting and 2 h postprandial levels but there was better correlation with 2‐h postprandial level. Conclusion The incidence of gestational diabetes is rising in South‐East Asian countries, especially in India. HBA1c could be a potential screening test for GDM.

Reliability of glycosylated hemoglobin in the diagnosis of gestational diabetes mellitus

“…In the current study, the median HbA1c level was significantly higher in women with GDM compared with women who had no GDM (4.8% vs 4.6%, P = .001). These findings are in agreement with the previous studies which reported a significantly higher HbA1c values in women with GDM compared with HbA1c values in women without GDM 10‐14 …”

“…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 . Interestingly, in a recent meta‐analysis enrolling 6406 pregnant women in eight studies, a good level of diagnostic accuracy (AUC = 0.825) of HbA1c for the diagnosis of GDM has been reported 20 …”

“…A previous study suggested the use of HbA1c at 5.95% as a cutoff point to confirm the diagnosis of GDM in women in India (28.6% and 97.2% for sensitivity and specificity, respectively) 26 . Recently, Dubey et al 14 have shown that by using a WHO 75 g OGTT criteria for the diagnosis of GDM, HbA1c at a cutoff ≥ 5.45% has the higher sensitivity (84.3%) and specificity (81.8%). Various levels of sensitivity and specificity (50.3% and 83.7%; 24.7% and 95.5% for the cutoffs of 5.4% and 5.7%, respectively) of HbA1 for the diagnosis GDM have been reported in the recent meta‐analysis 20 .…”

“…Moreover, HbA1c measurement if it is performed in early pregnancy could be of value in diagnosing preexisting diabetes 7‐9 . A number of studies have demonstrated elevated levels of HbA1c in women with GDM 10‐14 . Moreover, elevated levels of HbA1c during pregnancy were associated with adverse neonatal outcome 4,15 .…”

“…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 …”