Systematic review and meta-analysis.
Gestational diabetes mellitus (GDM) is glucose intolerance with onset or first diagnosis during the second or third trimester of pregnancy, which is clearly not either pre-existing type 1 or type 2 diabetes mellitus (T2DM). A previous diagnosis of GDM is an established risk factor for developing T2DM in later life, a fact that highlights the importance of postpartum screening to identify those at higher risk of progression and introduce strategies for disease prevention. Despite the magnitude of the risk, attendance for postpartum screening is suboptimal, as reported by studies from European countries, the United States, and Canada. An overall lack of awareness of the need for screening and the increased risk for future T2DM in this patient group is apparent. Healthcare providers lack familiarity with, and adherence to, guidelines and are uncertain as to whether the responsibility for screening these women lies with primary or secondary care. Meanwhile, the prevalence of T2DM is rising globally, with individuals diagnosed with the disease being at higher risk of all cause mortality.
Previous systematic reviews have highlighted the increased risk of developing T2DM after GDM. Kim et al, in 2002, identified a cumulative incidence of T2DM of between 2.6% to over 70% in studies with a total follow-up ranging from six weeks to 28 years; this incidence was highest in the first five postpartum years. In 2009, Bellamy et al showed a sevenfold higher risk of T2DM in patients with GDM in comparison with healthy controls (relative risk 7.43, 95% confidence interval 4.79 to 11.51). A further systematic review evaluated the rate of compliance with screening, and the prevalence of T2DM in Asian women, reporting incidences of between 2.8% and 58% in women with previous GDM.
Over recent decades, the demography of pregnant women has changed, with an increase in the rate of women giving birth at a more advanced age, and obesity rates also rising. Both these factors have led to a rise in the prevalence of GDM, establishing the disease as an imminent concern globally. From a public health perspective, this increased prevalence of GDM could contribute to the rising global health burden of obesity and T2DM. To deal with this problem, research has focused on improving the quality and effectiveness of screening and diagnosis of GDM. In addition to changes in the guidelines for GDM, changes have also occurred in the diagnostic criteria for T2DM, in an effort to identify populations at a higher risk. Thus there is a need to evaluate more recent evidence on the risk of progression to T2DM in women with previous GDM compared with those with a normoglycaemic pregnancy, investigating outcomes in ethnically diverse populations, and over a longer follow-up period.
Pancreatic disorders and therapy