Spotlight on gestational diabetes and CVD

Having gestational diabetes, or even elevated glucose levels during pregnancy, may be associated with increased risk of metabolic syndrome and cardiovascular disease (CVD) later, according to three recent studies.

Multiple recent studies analyzed the association between gestational diabetes and cardiovascular disease (CVD) risk after pregnancy.

First, an observational study in China, published by Diabetes Research and Clinical Practice on March 21, compared rates of metabolic syndrome among 1,263 women who had gestational diabetes mellitus (GDM) and 705 who hadn't developed it. Over a mean 3.53 years of follow-up, between 244 and 256 cases of metabolic syndrome (depending on the criteria used) were identified in the study population. Women with GDM were more than three times as likely to develop metabolic syndrome as those without (adjusted odds ratios, 3.66 [95% CI, 2.02 to 6.63] and 3.90 [95% CI, 2.13 to 7.14] with two criteria) and had higher adjusted odds of central obesity, hypertriglyceridemia, and hypertension individually. Risk of metabolic syndrome with GDM was relatively higher with older age during pregnancy and in normal-weight women versus overweight women. The study's findings show a higher risk of metabolic syndrome tied to GDM than has been reported previously, according to the authors. “Early lifestyle interventions might help prevent type 2 diabetes and metabolic syndrome in both overweight and normal weight women with GDM,” they concluded.

Another study, conducted in Canada and published by The Lancet Diabetes and Endocrinology on March 27, looked at the association between oral glucose challenge results during pregnancy and later development of CVD (defined as hospitalization for myocardial infarction, acute coronary syndrome, stroke, coronary artery bypass grafting, percutaneous coronary intervention, or carotid endarterectomy). It included 259,164 women who gave birth in 2007 to 2015 and were followed for a median of 3.9 years. Every 1-mmol/L increment in a patient's glucose challenge result was associated with a 13% increase in the adjusted odds of CVD (hazard ratio [HR], 1.13; 95% CI, 1.04 to 1.22). The association persisted when women with GDM were excluded, and the study found that even women with a challenge result between 7.2 and 7.7 mmol/L (130 to 139 mg/dL) had increased risk compared to those with a result of 7.1 mmol/L (128 mg/dL) or less (HR, 1.65, 95% CI, 0.99 to 2.76). The results show that the one-hour glucose challenge test “is a continuous variable that was associated with future risk of cardiovascular disease in both the general obstetrical population and women without gestational diabetes” and so might provide clinical value as a tool for risk stratification after pregnancy, the authors said.

Finally, a meta-analysis, published by Diabetologia on March 7, combined observational studies evaluating the association between GDM and subsequent CVD. Pooling nine studies with more than 5 million women, it found that women with GDM had almost twice the risk of future cardiovascular events (relative risk [RR], 1.98; 95% CI, 1.57 to 2.50). The association persisted when women who developed type 2 diabetes were excluded (RR, 1.56; 95% CI, 1.04 to 2.32). GDM was also associated with significantly increased risk of cardiovascular events in the first decade postpartum (RR, 2.31; 95% CI, 1.57 to 3.39). Based on these and other research findings, glucose testing during pregnancy appears to identify existing metabolic disorders, the authors said. “Thus, the diagnosis of GDM should be recognised as providing a unique window into a woman's future risk of CVD, and hence an opportunity for early risk modification and possibly prevention of the leading cause of mortality in women,” they wrote.