Increased cardiovascular risk found in women with glucose concentrations at the upper end of the normal range during pregnancy.
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.
In studies to date, gestational diabetes has consistently been associated with an increased future risk of cardiovascular disease, irrespective of the antepartum screening protocol or diagnostic criteria by which gestational diabetes is diagnosed. 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 investigators reasoned that the resultant heterogeneity in the severity of dysglycemia in women with gestational diabetes suggests that the relationship between gestational glycemia and subsequent cardiovascular disease probably extends into the non-diagnostic range. So, they hypothesized that glucose screening in pregnancy would identify future risk of cardiovascular disease in women who did not have 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 ≥200mg/dl(11.1 mmol/L) or a result between 140mg/dL.and 195mg/dL.(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 to: ≤86mg/dL to 89mg/dL.(4.8 – 4.9 mmol/L;) to 100mg/dL.(5.5 mmol/L) 100-115mg/dL.(5.6 to 6.2 mmol/L); 115-125mg/dL.(6.3 to 6.9 mmol/L) 126-143mg/dL.(7.0 to 7.9 mmol/L); and ≥145mg/dL(8.0 mmol/L.)
The primary outcome was cardiovascular disease (a composite of hospitalization for myocardial infarction, acute coronary syndrome, stroke, coronary artery bypass grafting, percutaneous coronary intervention, or carotid endarterectomy). All women were followed up from the index pregnancy until cardiovascular disease event, death, migration, or Sept 30, 2017, whichever came first.
259,164 women were identified as eligible for this study: 13,609 who had gestational diabetes, and 245,555 women without gestational diabetes. The women were followed up over a median 3·9 years (IQR 2·8–5·6) for the development of cardiovascular disease. Each 1 mmol/L increment in the glucose challenge test result was associated with a 13% higher risk of cardiovascular disease (after adjustment for age, ethnicity, income, and rurality, adjusted hazard ratio [HR] 1·13, 95% CI 1·04–1·22). This relationship persisted after excluding women with gestational diabetes (1·14, 1·01–1·28). In women without gestational diabetes, those with an abnormal glucose challenge test result (140mg/dL.)(≥7·8 mmol/L) and those with a result between 130mg./dL. and 140mg/dL.(( 7·2 and 7·7 mmol/L) had an increased risk of cardiovascular disease (HR 1·94, 95% CI 1·29–2·92; and 1·65, 0·99–2·76, respectively), compared with those with a result of 128mg/dL.(7·1 mmol/L) or less (overall p=0·003).
In the group of women without gestational diabetes, CV risk was higher in patients with an abnormal glucose screening test 140mg/dL. (≥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
“Glucose 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.
- Glucose screening during pregnancy can help identify future cardiovascular risk among women with and without gestational diabetes.
- Each 1 mmol/L increment in the glucose challenge test result was associated with a 13% higher risk of cardiovascular disease
- The relationship between gestational glycaemia and subsequent risk of cardiovascular disease extends into the normoglycemic range.
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