The current blood glucose screening test used for all pregnant women in Ontario could predict future heart disease

27/03/2019

A test that is currently used on all pregnant women in Ontario provides predictive information on their future risk of developing cardiovascular disease in the years after giving birth, according to a new study by researchers at ICES and Mount Sinai Hospital part of Sinai Health System.

In the past decade, studies from several countries (Canada, US, UK, Sweden, France and Israel) have consistently reported that women who have gestational diabetes mellitus (GDM) have an elevated risk of developing cardiovascular disease (including myocardial infarction, acute coronary syndrome, stroke, coronary artery bypass grafting, percutaneous coronary intervention or carotid endarterectomy) in the years after giving birth, regardless of the screening test used to diagnose gestational diabetes.

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In the study published today in The Lancet Diabetes & Endocrinology, the researchers found that the current glucose screening test, used in pregnancy to diagnose gestational diabetes, can identify future risk of heart disease in women who do not have gestational diabetes but do have mildly elevated blood glucose levels.

“The glucose screening of pregnant women that is performed in current obstetrical practice offers the previously-unrecognized capacity to identify future risk of cardiovascular disease in both those with gestational diabetes and those who are otherwise classified clinically as normal, despite elevated readings,” says Dr. Baiju Shah, an author of the study, an endocrinologist with Sunnybrook Health Sciences Centre and a senior scientist at ICES.

The researchers evaluated all women in Ontario who had a glucose challenge test in pregnancy with a delivery between July 2007 and December 2015. The study included 12,307 women who had gestational diabetes and 246,857 women without. The women were followed for nearly four years after delivery for the development of cardiovascular disease. There were 138 cardiovascular events in the entire study.

The researchers found that each one mmol/L increment in blood glucose on this test is associated with a 13 per cent higher risk of cardiovascular disease in the following years in both the general obstetrical population and in women who do not have gestational diabetes. Among women who do not have gestational diabetes, those with either abnormal results or even a result in the upper end of the normal range on this test comprise clinically-identifiable patient populations at higher cardiovascular risk than their peers.

“Our findings show that a screening test that is already being performed in clinical practice has the capacity to identify future risk of cardiovascular disease in women at an early point in the development of the disease, offering unique insight into health risks well beyond pregnancy,” says Dr. Ravi Retnakaran, an author of the study and an endocrinologist with Leadership Sinai Centre for Diabetes at Mount Sinai Hospital and an investigator with the Lunenfeld-Tanenbaum Research Institute.

Author block: Ravi Retnakaran and Baiju R Shah.

The report “Glucose screening in pregnancy and future risk of cardiovascular disease in women: a retrospective, population-based cohort study,” is published in the March 27 issue of The Lancet Diabetes & Endocrinology.

ICES is an independent, non-profit research institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. In October 2018, the institute formerly known as the Institute for Clinical Evaluative Sciences formally adopted the initialism ICES as its official name. For the latest ICES news, follow us on Twitter: @ICESOntario

About the Lunenfeld-Tanenbaum Research Institute: The Lunenfeld-Tanenbaum Research Institute, part of Sinai Health System, is a leading biomedical research centre, ranking amongst the top biomedical research institutes in the world. Established in 1985, the institute is profoundly advancing understanding of human biology in health and disease. Many of the breakthroughs that began as fundamental research have resulted in new and better ways to prevent, diagnose and treat prevalent conditions. The institute is affiliated with the University of Toronto and is focused on women's and infants' health, cancer biology, stem cell biology, neurobiology, diabetes, arthritis, health systems research, population health services and solutions, and systems biology. www.lunenfeld.ca.