Gestational Diabetes Mellitus: Clinical Predictors and Long-Term Risk of Developing Type 2 Diabetes

TLDR

The study aimed to quantify the long‑term risk of type 2 diabetes after gestational diabetes and identify maternal and neonatal predictors of later diabetes. A retrospective cohort of 5,470 GDM patients and 783 controls was followed with survival analysis from 1971 to 2003. GDM patients had a 9.6‑fold higher long‑term diabetes risk, with a 25.8 % cumulative incidence at 15 years; insulin use, Asian ethnicity, and elevated 1‑hour glucose were strong predictors, underscoring the need for extended monitoring of these women.

Abstract

OBJECTIVE—We sought to determine the long-term risk of type 2 diabetes following a pregnancy complicated by gestational diabetes mellitus (GDM) and assess what maternal antepartum, postpartum, and neonatal factors are predictive of later development of type 2 diabetes. RESEARCH DESIGN AND METHODS—This was a retrospective cohort study using survival analysis on 5,470 GDM patients and 783 control subjects who presented for postnatal follow-up at the Mercy Hospital for Women between 1971 and 2003. RESULTS—Risk of developing diabetes increased with time of follow-up for both groups and was 9.6 times greater for patients with GDM. The cumulative risk of developing type 2 diabetes for the GDM patients was 25.8% at 15 years postdiagnosis. Predictive factors for the development of type 2 diabetes were use of insulin (hazard ratio 3.5), Asian origin compared with Caucasian (2.1), and 1-h blood glucose (1.3 for every 1 mmol increase above 10.1 mmol). BMI was associated with an increased risk of developing type 2 diabetes but did not meet the assumption of proportional hazards required for valid inference when using Cox proportional hazards. CONCLUSIONS—While specific predictive factors for the later development of type 2 diabetes can be identified in the index pregnancy, women with a history of GDM, as a group, are worthy of long-term follow-up to ameliorate their excess cardiovascular risk.