The prevalence of abnormal glucose tolerance up to 5 years after an index pregnancy complicated by gestational diabetes defined using International Association of Diabetes and Pregnancy Study Groups criteria

Abstract

Introduction Gestational diabetes (GDM) is associated with an increased future risk of type 2 diabetes, but the risk among women diagnosed with the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria is unknown. Therefore, we wished to determine the prevalence of abnormal glucose tolerance, metabolic syndrome, and insulin resistance in women with previous IADPSG-defined GDM. Methods We invited women with previous IADPSG-defined GDM up to 5 years post-partum for retesting with OGTT and HbA1c. A control group known to have normal glucose tolerance (NGT) at the same time also attended. Results were analysed using descriptive statistics, logistic regression, linear regression, decision tree analysis, and multidimensional scaling methods. Results 270 women with previous GDM and 388 women with NGT in pregnancy attended (mean of 2.6 and 3.3 years follow-up respectively). 25.9% percent of women with previous GDM and 3.6% of women with previous NGT had AGT. Fasting and 2-hour glucose on pregnancy OGTT, gestational week diagnosed, family history, and BMI, were associated with AGT at retesting. The predictive power of the models was suboptimal. 25.3% percent of women with previous GDM and 6.6% with previous NGT had metabolic syndrome, while the prevalence of insulin resistance (HOMA2-IR>1.8) was 33.6% in women with previous GDM vs. 9.1% in those with NGT. Combining HbA1c ¿ 39 mmol/mol with FPG of ¿ 5.6 mmol/L yielded a sensitivity of 90% and specificity of 84% for detection of AGT. Conclusions IADPSG criteria for GDM identify a cohort at significant risk of metabolic disturbance up to 5 years post-partum. Identification of women at highest risk using routine clinical variables is not a useful strategy. Follow-up should be as frequent as for those meeting older GDM criteria. Combining HbA1c and FPG to detect AGT may be useful for longer-term follow-up