Concomitant Gestational Diabetes and Hypertensive Disorder Increase Long-term Postpartum CVD Risk

Women who experience both gestational diabetes (GD) and gestational hypertensive disorder (GHTD) during pregnancy may be at 2 times greater absolute risk of future cardiovascular disease (CVD) than women who do not develop either condition. Further, according to a team of Canadian researchers, the risk for CVD linked to having the combination of conditions can become more pronounced over time than the risk observed among women having either condition alone.

“The combination of GHTD and GD may represent a more severe form of maladaptive pregnancy changes that substantially contribute to future CVD," write study authors. The extent of CVD risk observed when the conditions occur together has practical clinical implications, they add, underscoring the importance of systematic detection of GHTD and GD during pregnancy to help predict and reduce the risk of future CVD.

The investigators, led by led by Baiju R. Shah, MD, PhD, associate professor at the Institute for Clinical Evaluative Studies in Toronto cite a growing body of evidence showing that each condition alone developed during a woman’s pregnancy increases the risk of CVD, and then they point to a paucity of research on the joint influence which they hope their study will augment. 

“The combination of GHTD and GD may represent a more severe form of maladaptive pregnancy changes that substantially contribute to future CVD."

Shah and colleagues conducted a population-based cohort study using data from administrative health care databases maintained by the Ministry of Health and Long-Term Care of Ontario. Using access to records of all women in Ontario with a GHTD and/or GD diagnosis and a live birth singleton delivery between July 1, 2007, and March 31, 2018, investigators identified 866 295 stud participants.

Diagnostic codes were used to identify eligible participants and exclusion criteria eliminated potential participants with pregravid diabetes, hypertension, or CVD.

The team’s primary outcome of interest was incident CVD, a composite of hospitalization for myocardial infarction, acute coronary syndrome, stroke, coronary artery bypass grafting, percutaneous coronary intervention, or carotid endarterectomy. Associations were assessed using Cox regression models, with adjustment for relevant cardiometabolic risk factors.

FINDINGS

Among the final 866 295 participants, the mean age was 30 (SD, 5.6) years. Overall, 4.9% had isolated GHTD, 6.1% had isolated GD, and 0.6% had both conditions. Over a follow-up period of 12.8 years (7 million person-years) investigators report there were 1999 CVD events. Of those 867 occurred during the first 5 years postpartum and 1162 events occurred after the first 5 years postpartum.

Women with GD and GHTD were older, less likely to have a premature delivery and prior GHTD, but more likely to have developed postpartum diabetes, and postpartum hypertension.

First 5 years

During the first 5 years after delivery, the team found no association between co-occurrence of GHTD and GD (aHR, 1.42 [95% CI, 0.78-2.58] p=.25) or GD alone (aHR, 0.80 [95% CI, 0.60-1.06]) and incident CVD.

Compared with no GHTD or GD during this time period, however, investigators did observe an association between isolated GHTD and risk of incident CVD (aHR, 1.90 [95% CI, 1.51-2.35]). Also, after full adjustment for confounding variables including postpartum hypertension and postpartum diabetes, isolated GHTD was associated with a greater risk for incident CVD than isolated GD (aHR, 2.32; 95% CI, 1.62-3.30; P < .001) in a direct comparison.

After 5 years

When the research team assessed CVD risk after the initial 5 years following index birth, they found that isolated GHTD (aHR, 1.41 [95% CI, 1.12-1.76]) and co-occurrence of GHTD and GD (aHR, 2.43 [95% CI, 1.60-3.67] p<.001) were each associated with a higher risk of incident CVD vs no GHTD and no GD.

Shah and colleagues observed no association between isolated GD and incident CVD.

The investigators say that to their knowledge this is the largest study to examine the joint association of GHTD and GD with postpartum CVD and that the findings corroborate those of a prior smaller study although that one did not comprehensively control for confounding.

In conclusion they write: “This cohort study found that over time, co-occurrence of GD and GHTD was associated with a much greater postpartum CVD risk than the individual conditions. The systematic identification of both GHTD and GD in obstetrical practice offers an opportunity for a more effective CVD prevention among young women of childbearing age.”

Reference: Tcheugui JBE, Guan J, Fu L, et al. Association of concomitant gestational hypertensive disorders and gestational diabetes with cardiovascular disease. JAMA Netwk Open. 2022;5:e2243618. doi:10.1001/jamanetworkopen.2022.43618