Glucose screening during pregnancy can predict future cardiovascular (CV) risk in women with and without gestational diabetes, according to study results published in The Lancet Diabetes & Endocrinology. CV risk was found to be higher with abnormal glucose screening tests, but there was also increased CV risk in women with glucose concentrations at the upper end of the normal range.
Previous studies have shown gestational diabetes is a risk factor for CV morbidity. The study investigators hypothesized that glucose screening during pregnancy can predict CV disease in women who do not have gestational diabetes. The goal of their study was to investigate the association between glucose challenge test results during pregnancy and future CV risk in the general obstetrical population and women without gestational diabetes.
The retrospective population-based cohort study used administrative databases from the Ministry of Health and Long-Term Care of Ontario, Canada. The study enrolled all women in the Ontario database who had a 50-g oral glucose challenge test during pregnancy at between 24 and 28 weeks’ gestation and who delivered between July 2007 and December 2015.
Gestational diabetes was defined as 1-hour post-challenge plasma glucose concentration ≥11.1 mmol/L or a result between 7.8 and 11.0 mmol/L with a record of a diabetes diagnosis on the delivery hospital record. The participants were divided into 6 equal groups based on the glucose screening test results: ≤4.8 mmol/L; 4.9 to 5.5 mmol/L; 5.6 to 6.2 mmol/L; 6.3 to 6.9 mmol/L; 7.0 to 7.9 mmol/L; and ≥8.0 mmol/L.
The primary study outcome was CV disease, including hospitalization for myocardial infarction, acute coronary syndrome, stroke, coronary artery bypass grafting, percutaneous coronary intervention, or carotid endarterectomy. Follow-up continued from the index pregnancy until CV event, death, migration, or September 30, 2017.
Of 259,164 women who underwent a screening glucose challenge in pregnancy, gestational diabetes was documented in 13,609 women (5.3%).
Over a median follow-up of almost 4 years, 138 CV disease events were recorded in the study population. There was a positive association between 1-hour post-challenge glucose concentration and the likelihood of a CV event; each 1 mmol/L increase in glucose concentration was associated with a 13% higher risk for CV disease (adjusted hazard ratio [HR], 1.13; 95% CI, 1.04-1.23; P =.003). The association remained significant even after the exclusion of twin and multiple gestation pregnancies (HR, 1.13; 95% CI, 1.04-1.23; P =.004).
In the group of women without gestational diabetes, CV risk was higher in patients with an abnormal glucose screening test (≥7.8 mmol/L), but there was also increased CV risk in patients with a glucose concentration at the upper end of the normal range (7.2-7.7 mmol/L) compared with ≤7.1 mmol/L (HR, 1.94; 95% CI, 1.29-2.92; and HR, 1.65; 95% CI, 0.99-2.76, respectively; overall P =.003).
The study had several limitations, including a lack of information regarding CV risk factors, such as lipid concentration, blood pressure measurements, body mass index, family history, or lifestyle factors and the relatively short follow-up period.
“[G]lucose screening of pregnant women that is done in current obstetrical practices offers the capacity to identify future risk [for CV disease] in both those with gestational diabetes and those who are classified clinically as not having gestational diabetes,” concluded the researchers.
Retnakaran R, Shah BR. Glucose screening in pregnancy and future risk ofcardiovascular disease in women: a retrospective, population-based cohort study [published online March 27, 2019]. Lancet Diabetes Endocrinol. doi:10.1016/S2213-8587(19)30077-4