Catherine Crowe

ATLANTIC DIP: simplifying the follow-up of women with previous gestational diabetes

OBJECTIVE Previous gestational diabetes (GDM) is associated with a significant lifetime risk of type 2 diabetes. In this study, we assessed the performance of HbA1c and fasting plasma glucose (FPG) measurements against that of 75 g oral glucose tolerance testing (OGTT) for the follow-up screening of women with previous GDM. METHODS Two hundred and sixty-six women with previous GDM underwent the follow-up testing (mean of 2.6 years (s.d. 1.0) post-index pregnancy) using HbA1c (100%), and 75 g OGTT (89%) or FPG (11%). American Diabetes Association (ADA) criteria for abnormal glucose tolerance were used. DESIGN, COHORT STUDY, AND RESULTS The ADA HbA1c high-risk cut-off of 39 mmol/mol yielded sensitivity of 45% (95% CI 32, 59), specificity of 84% (95% CI 78, 88), negative predictive value (NPV) of 87% (95% CI 82, 91) and positive predictive value (PPV) of 39% (95% CI 27, 52) for detecting abnormal glucose tolerance. ADA high-risk criterion for FPG of 5.6 mmol/l showed sensitivity of 80% (95% CI 66, 89), specificity of 100% (95% CI 98, 100), NPV of 96% (95% CI 92, 98) and PPV of 100% (95% CI 91, 100). Combining HbA1c ≥39 mmol/mol with FPG ≥5.6 mmol/l yielded sensitivity of 90% (95% CI 78, 96), specificity of 84% (95% CI 78, 88), NPV of 97% (95% CI 94, 99) and PPV of 56% (95% CI 45, 66). CONCLUSIONS Combining test cut-offs of 5.6 mmol/l and HbA1c 39 mmol/mol identifies 90% of women with abnormal glucose tolerance post-GDM (mean 2.6 years (s.d.1.0) post-index pregnancy). Applying this follow-up strategy will reduce the number of OGTT tests required by 70%, will be more convenient for women and their practitioners, and is likely to lead to increased uptake of long-term retesting by these women whose risk for type 2 diabetes is substantially increased.

Abnormal glucose tolerance post-gestational diabetes mellitus as defined by the International Association of Diabetes and Pregnancy Study Groups criteria

OBJECTIVE An increase in gestational diabetes mellitus (GDM) prevalence has been demonstrated across many countries with adoption of the International Association of the Diabetes and Pregnancy Study Groups (IADPSG) diagnostic criteria. Here, we determine the cumulative incidence of abnormal glucose tolerance among women with previous GDM, and identify clinical risk factors predicting this. DESIGN Two hundred and seventy women with previous IADPSG-defined GDM were prospectively followed up for 5years (mean 2.6) post-index pregnancy, and compared with 388 women with normal glucose tolerance (NGT) in pregnancy. METHODS Cumulative incidence of abnormal glucose tolerance (using American Diabetes Association criteria for impaired fasting glucose, impaired glucose tolerance and diabetes) was determined using the Kaplan-Meier method of survival analysis. Cox regression models were constructed to test for factors predicting abnormal glucose tolerance. RESULTS Twenty-six percent of women with previous GDM had abnormal glucose tolerance vs 4% with NGT, with the log-rank test demonstrating significantly different survival curves (P<0.001). Women meeting IADPSG, but not the World Health Organization (WHO) 1999 criteria, had a lower cumulative incidence than women meeting both sets of criteria, both in the early post-partum period (4.2% vs 21.7%, P<0.001) and at longer-term follow-up (13.7% vs 32.6%, P<0.001). Predictive factors were glucose levels on the pregnancy oral glucose tolerance test, family history of diabetes, gestational week at testing, and BMI at follow-up. CONCLUSIONS The proportion of women developing abnormal glucose tolerance remains high among those with IADPSG-defined GDM. This demonstrates the need for continued close follow-up, although the optimal frequency and method needs further study.

The prevalence of metabolic syndrome up to 5 years post-partum in patients with a history of gestational diabetes mellitus

Metabolic syndrome (MetS) is associated with cardiovascular mortality and increased risk of type 2 diabetes.

ATLANTIC DIP: The prevalence of pre-diabetes/type 2 diabetes in an Irish population with gestational diabetes mellitus 1-5 years post index pregnancy

The ATLANTIC-DIP (diabetes in pregnancy) programme showed 18% of women with gestational diabetes mellitus (GDM) screened with a 75g oral glucose tolerance test (OGTT) 12 weeks post-partum demonstrated glucose intolerance. However, long-term data on progression to type 2 diabetes (T2DM) post gestational diabetes (GDM) in an Irish population is lacking.

Validation of a diabetes risk score in identifying patients at risk of progression to abnormal glucose tolerance post partum

FINDRISC (Finnish Diabetes Risk Score) is a risk assessment tool widely used for the prediction of the development of type 2 diabetes (T2DM), combining a questionnaire with simple anthropometric measurements to identify patients at risk of developing diabetes, with increasing score (0-26) signifying increased risk. A cut off score of 9 has previously been proposed (with drug-treated DM as the endpoint) with a positive predictive value (PPV) of 0.12 and negative predictive value (NPV) of 0.99, area under receiver operating characteristic curve (AuROC)=0.80. It has been well validated in the general population.