Diagnostic Accuracy of HbA1c as Early Prenatal Screening Tool in Gestational Diabetes Mellitus Taking OGTT as Gold Standard

Abstract

Objective: To assess the diagnostic accuracy of glycated hemoglobin (HbA1c) as early prenatal screening tool in GDM taking oral glucose tolerance test (OGTT) as gold standard.

Methodology: This Cross-sectional study was done at Obstetrics & Gynecology department, CMH Kharian from January 2023 to July 2023. A total of 214 Patients fulfilling the inclusion criteria from gynecology department of CMH Kharian were enrolled in the study after getting permission from ethical committee. HbA1c was done on booking visit and GDM was recorded if it was ?6%. All patients were called for follow up at 24 weeks of gestation for OGTT to diagnose whether these patients have developed GDM or not.

Results: The mean age of all subjects was 27.29±4.61 years. According to HbA1c, 73(34.11%) females had ? 6% and 141(65.89%) females had HbA1C < 6%. According to OGTT, 65(30.37%) cases were positive for GDM.   On comparing diagnostic accuracy, 61 cases were positive on both diagnostic methods whereas 137 females were negative on both modalities. 12 females were positive on HbA1c and were negative on OGGT while 4 were positive on OGGT but negative on HbA1c.  The sensitivity, specificity, PPV, NPV, and diagnostic accuracy was 93.85%, 91.95%, 83.56%, 97.16% and 92.52% respectively. 

Conclusion: Through the findings of this study, it was concluded that HbA1C has high diagnostic accuracy.  It can be used to identify such patients in early trimester. So, females with high HbA1C (?6%) should be enrolled for interventional strategies for better maternal & perinatal outcomes.