Insulin requiring Gestational Diabetes: Risk factors and correlation with postpartum diabetes and prediabetes.

Objective: A2 gestational diabetes mellitus (A2GDM) is a more severe form of GDM that requires additional medical intervention, such as insulin or oral antidiabetic drug (OAD). The present study explored the determinants of A2GDM and analyzed the associated risk of post-partum diabetes or prediabetes.

Methods: This retrospective study included 247 pregnant women, diagnosed with GDM and followed up until delivery at the Obstetric Medicine Clinic of King Abdulaziz University Hospital, Jeddah, Saudi Arabia, between January 2014 and January 2018. Women with personal history of diabetes or prediabetes were excluded. Collected data included patient's age, body mass index, personal history of thyroid dysfunction and GDM, HbA1c level at diagnosis, management of GDM (diet only, insulin, or OAD), and postpartum metabolic assessment.

Results: The prevalence of A2GDM was 29.6%, of which 21.5% were insulin-requiring and 8.1% were OAD-requiring cases. The risk of A2GDM was independently associated with a positive history of GDM (OR=3.19, 95% CI = 1.41-7.20) and HbA1c >7% (OR=8.66, 95%CI = 2.15- 34.94); the model explained 20% of the variance of A2GDM. The postpartum assessment showed that 10.1% have developed prediabetes, while no one developed overt diabetes. Postpartum prediabetes was independently predicted by age category ≥45 years (OR=39.94, 95%CI = 4.62-345.06), history of GDM (OR=0.18, 95%CI = 0.03 - 0.97), and A2GDM (OR=6.96, 95%CI = 1.91-25.42).

Conclusion: Approximately one-third of GDM patients in our institution require insulin or OAD for glycemic control and are at high risk of developing prediabetes postpartum. Adherence to and effectiveness of medical nutrition therapy should be further explored among GDM patients to improve their glycemic control and both maternal and fetal prognosis.