Screening and Diagnosis of Gestational Diabetes Mellitus Using 75-g Oral Glucose Tolerance Test Following the WHO, ADA, and IADPSG Criteria

Aim: We aim to compare the World Health Organization (WHO), American Diabetes Association (ADA), and the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria to diagnose gestational diabetes mellitus in Metro Manila, Philippines.Materials and methods: We used a retrospective cohort study design and reviewed 75-g oral glucose tolerance test results of 919 pregnant women at selected hospital-based and free-standing laboratories in Metro Manila. We used three criteria for diagnosing GDM namely, WHO (fasting: 7.0 mmol/L; 2-hour value: 11.1 mmol/L), ADA (fasting: 5.28 mmol/L; 1-hour: 10 mmol/L; 8.61 mmol/L), or IADPSG (fasting: 5.11 mmol/L; 1 hour: 10 mmol/L; 2-hour value: 8.5 mmol/L) and computed and compared their diagnostic sensitivity, diagnostic specificity, positive predictive value (PPV) and negative predictive value (NPV).Results: Following the WHO criteria, we found 48 GDM patients; using ADA criteria, 150 have GDM; and using IADPSG criteria, 269 women have GDM. Applying the IADPSG criteria to the population would increase the rate of GDM from 5.22% (WHO) to 16.32% (ADA) to 29.27%. Giving the highest prevalence rate, we used IADPSG criteria as the standard to compute for diagnostic sensitivity, diagnostic specificity, NPV and PPV. Results showed that the diagnostic sensitivity of OGTT using ADA criteria is 55.97%, which is higher than using the WHO criteria (17.91%). ADA criteria also has a higher NPV of 84.66% as compared with WHO criteria NPV of 74.74%. In terms of diagnostic specificity, both ADA and WHO criteria have 100% specificity.Conclusions: The use of IADPSG criteria instead of ADA and WHO criteria would result in a considerable increase in the prevalence rate of GDM, which would lessen cases of misdiagnosis. Further, standardizing the criteria for diagnosis will prevent pregnancy complications due to GDM. A single global criterion for the diagnosis of GDM is a must to strengthen its diagnosis and protect both the mother and the baby from complications.