USA: Gestational Glucose Intolerance and Future Diabetes Risk

A recent study published in Diabetes Care has identified gestational glucose intolerance (GGI) as a risk factor for future diabetes. Gestational glucose intolerance is an abnormal initial gestational diabetes mellitus (GDM) screening test without a GDM diagnosis.

Pregnant women are universally screened for gestational diabetes. Gestational glucose intolerance is not a recognized risk factor for diabetes. Daryl J. Selen, Diabetes Unit, Massachusetts General Hospital, Boston, MA, and colleagues investigated an association between GGI and diabetes after pregnancy.

Study Overview

To address the question, "Is gestational glucose intolerance a risk factor for future diabetes?" the researchers' team conducted a retrospective cohort study of individuals followed for prenatal and primary care. GGI is an abnormal screening glucose-loading test result at more than 24 weeks gestation with an OGTT (oral glucose tolerance test) that did not meet the criteria for gestational diabetes. Incident diabetes was the study's primary outcome. To compare the risk of incident diabetes in patients with GGI and normal glucose tolerance, they used Cox proportional hazards models with time-varying exposures and covariates.

Study Findings

• From 16,836 individuals, there were 2,943 pregnancies with gestational glucose intolerance, 20,359 with normal glucose tolerance, and 909 with gestational diabetes.
• After a median of 8.4 years of follow-up, 428 people developed diabetes.
• People with gestational glucose intolerance had increased diabetes risk compared to those with normal glucose tolerance in pregnancy (adjusted hazard ratio [aHR] 2.01).
• Diabetes risk increased with the number of abnormal OGTT values (zero, aHR 1.54; one, aHR 2.97; GDM, aHR 8.26 for each compared with normal glucose tolerance).
• The fraction of cases of diabetes ten years after delivery attributable to GGI and GDM was 8.5% and 28.1%, respectively.

"Gestational glucose intolerance confers an increased risk of future diabetes," the authors wrote. "Routinely available clinical data identify an unrecognized group in which enhanced diabetes screening and prevention may be beneficial."

Reference

Daryl J. Selen, Tanayott Thaweethai, Carolin C.M. Schulte, Sarah Hsu, Wei He, Kaitlyn James, Anjali Kaimal, James B. Meigs, Camille E. Powe; Gestational Glucose Intolerance and Risk of Future Diabetes. Diabetes Care 2022; dc221390. https://doi.org/10.2337/dc22-1390