One elevated oral glucose tolerance test value in pregnancy increases the risk for future diabetes mellitus type 2.

PURPOSE

Women with only one elevated 100 g OGTT value are not considered as having gestational diabetes mellitus (GDM) and therefore there are no recommendations to address this population as a risk group for type 2 diabetes mellitus (T2DM). We aimed to elucidate whether one elevated OGTT value increases the risk for T2DM.

METHODS

A retrospective population-based cohort study of women with a first diagnosis of GDM who delivered between 1991 and 2011 was conducted. Women were divided according to GDM diagnosis criteria into three groups: (1) at least two elevated values of Carpenter and Coustan criteria (C&C; N = 209), (2) At least two elevated values of the National Diabetes Data Group (NDDG) criteria (NDDG2; N = 290) and (3) only one elevated value of the NDDG criteria (NDDG1; N = 226). A fourth group comprising women without GDM was included (control; N = 352). The primary outcome was the development of T2DM.

RESULTS

The mean follow-up was 12.4 ± 5.3 years and the mean age at follow-up was 43.0 ± 5.7 years. The rate of T2DM in the control, C&C, NDDG1 and NDDG2 groups were 5%, 18%, 19% and 31%, respectively. All GDM diagnoses were independent risk factors for T2DM in multivariable Cox regression when compared to controls, adjusted hazard ratio and 95% CI: C&C 7.8 [95% CI 3.7-16.4], NDDG1 5.5 [2.6-11.6], and NDDG2 10.5 [5.2-21.4]. Additional independent risk factors were parity, fasting and 1-h post-glucose load of the OGTT and insulin use.

CONCLUSIONS

Women with one elevated OGTT value using the NDDG criteria are at increased risk for T2DM. Further studies are needed to decide whether those women should be considered a focus group for long-term surveillance and T2DM prevention interventions.