Association between gestational diabetes and cardiovascular disease within 24 months postpartum

Cardiovascular disease is the leading cause of death among women in the United States. It is well established that gestational diabetes mellitus is associated with an overall lifetime increased risk of cardiometabolic disease, even among those without intercurrent type 2 diabetes. However, the association between gestational diabetes mellitus and short-term risk of cardiovascular disease is unclear. Establishing short-term risks of cardiovascular disease for patients with gestational diabetes mellitus has significant potential to inform early screening and targeted intervention strategies to reduce premature cardiovascular morbidity among women.

This study aimed to compare the risk of cardiovascular disease diagnosis in the first 24 months postpartum between patients with and without gestational diabetes mellitus.

Our longitudinal population-based study included pregnant individuals with deliveries from 2007 to 2019 in the Maine Health Data Organization's All Payer Claims Database. We excluded records with gestational age <20 weeks, non-Maine residence, multifetal gestation, no insurance in the month of delivery or the 3 months before pregnancy, an implausibly short interval until next pregnancy (<60 days), pregestational diabetes mellitus, and any prepregnancy diagnosis of the cardiovascular conditions being examined postpartum. Gestational diabetes mellitus and cardiovascular disease (heart failure, ischemic heart disease, arrhythmia/cardiac arrest, cardiomyopathy, cerebrovascular disease/stroke, and new chronic hypertension) were identified by International Classification of Diseases 9/10 diagnosis codes. Cox proportional hazards models were used to estimate hazard ratios, adjusting for potential confounding factors. We assessed whether the association between gestational diabetes mellitus and chronic hypertension was mediated by intercurrent diabetes mellitus.

Among the 84,746 pregnancies examined, the cumulative risk of cardiovascular disease within 24 months postpartum for those with vs without gestational diabetes mellitus was 0.13% vs 0.20% for heart failure, 0.16% vs 0.14% for ischemic heart disease, 0.60% vs 0.44% for cerebrovascular disease/stroke, 0.22% vs 0.16% for arrhythmia/cardiac arrest, 0.20% vs 0.20% for cardiomyopathy, and 4.19% vs 1.83% for new chronic hypertension. After adjusting for potential confounders, those with gestational diabetes had an increased risk of new chronic hypertension (adjusted hazard ratio, 1.56; 95% confidence interval, 1.32-1.86) within the first 24 months postpartum compared with those without gestational diabetes. There was no association between gestational diabetes and ischemic heart disease (adjusted hazard ratio, 0.75; 95% confidence interval, 0.34-1.65), cerebrovascular disease/stroke (adjusted hazard ratio, 1.13; 95% confidence interval, 0.78-1.66), arrhythmia/cardiac arrest (adjusted hazard ratio, 1.16; 95% confidence interval, 0.59-2.29), or cardiomyopathy (adjusted hazard ratio, 0.75; 95% confidence interval, 0.40-1.41) within the first 24 months postpartum. Those with gestational diabetes appeared to have a decreased risk of heart failure within 24 months postpartum (adjusted hazard ratio, 0.45; 95% confidence interval, 0.21-0.98). Our mediation analyses estimated that 28% of the effect of gestational diabetes on new chronic hypertension was mediated through intercurrent diabetes mellitus.

Patients with gestational diabetes mellitus have a significantly increased risk of new chronic hypertension as early as 24 months postpartum. Most of this effect was not due to the development of diabetes mellitus. Our findings suggest that all women with gestational diabetes need careful monitoring and screening for new chronic hypertension in the first 2 years postpartum.