Researchers examined the association between a history of gestational diabetes and the risk of developing type 2 diabetes and cardiovascular disease postpartum.
Gestational diabetes (GDM) is a well-documented risk factor for developing type 2 diabetes later in life and carries up to a 70% lifetime risk. However, little is known about the association between gestational diabetes and cardiovascular disease. Only a few studies have previously investigated this association, all of which reported an increased risk of cardiovascular events in women with a history of gestational diabetes. Current guidelines only make recommendations on diabetes screening and lifestyle changes postpartum for women diagnosed with gestational diabetes, however, no recommendations are made with regard to cardiovascular risk factors.
Researchers in the United Kingdom examined the risk of cardiovascular disease in women with a history of gestational diabetes and published their findings in PLOS Medicine. The retrospective cohort study used a large UK primary care database to compare cardiovascular outcomes in women diagnosed with gestational diabetes and pregnant women without gestational diabetes, as the control group, matched by age and pregnancy timeline. The researchers assessed the participants for a clinical diagnosis of coronary artery disease and cerebrovascular disease (stroke or transient ischemic attack) as primary outcomes and incidence of type 2 diabetes and hypertension as secondary outcomes.
Gestational Diabetes Linked to Heart Disease
After adjusting for risk factors and possible confounders, their analysis showed that women diagnosed with gestational diabetes were over 20 times more likely to develop type 2 diabetes later on in life. These women also had a two times greater risk of developing hypertension and were two and a half times more likely to develop coronary artery disease. However, no increased risk was identified for cerebrovascular disease. Over the 25-year period, the researchers reviewed from 1990 to 2016, the incidence of type 2 diabetes, hypertension, and coronary artery disease was persistently higher in women with gestational diabetes compared to control women.
More Screening Necessary
Also of note in the study’s findings were the poor postpartum screening rates for type 2 diabetes and cardiovascular risk factors in women diagnosed with gestational diabetes. The researchers found that only slightly more than half of women with gestational diabetes had a glycemic measurement performed in their first year postpartum, which decreased to less than 40% in the second and third year postpartum. A quarter of the women did not have any glycemic measurement done at all in the first three years following delivery. Similarly, blood pressure, BMI, and smoking status were only measured in approximately 50% or less of women with gestational diabetes in their first year postpartum, which then declined in subsequent years.
Overall, results indicate that a history of gestational diabetes not only puts women at risk of type 2 diabetes but for cardiovascular diseases as well. This finding also aligns with prior studies that showed a similar association. The study was limited by a lack of complete baseline characteristics, such as ethnicity or order of pregnancies, which therefore limited more in-depth analysis of these factors that could affect outcomes. Further, not all women with gestational diabetes may have been captured as only those documented in primary medical records were analyzed and selective documentation of more severe gestational diabetes may have led to an overestimation of the effect size.
However, this study was the first UK and largest population-based study of women with gestational diabetes to examine cardiovascular disease incidence. The study proposes that current guidelines should be reviewed to include screening recommendations on managing cardiovascular risk factors in this subgroup of at-risk women who may benefit from targeted prevention and interventions.
Written by Maggie Leung, PharmD
Reference: Daly, B., Toulis, K. A., Thomas, N., Gokhale, K., Martin, J., Webber, J., . . . Nirantharakumar, K. (2018). Increased risk of ischemic heart disease, hypertension, and type 2 diabetes in women with previous gestational diabetes mellitus, a target group in general practice for preventive interventions: A population-based cohort study. PLOS Medicine, 15(1). doi:10.1371/journal.pmed.1002488