Gestational Diabetes and Incident Heart Failure: A Cohort Study

OBJECTIVE: To assess whether gestational diabetes mellitus (GDM) is associated with an increased risk of heart failure (HF). RESEARCH DESIGN AND METHODS: We conducted a population-based cohort study using information from the Ministry of Health and Long-Term Care of Ontario (Canada) health care administrative databases. We identified all women in Ontario with a GDM diagnosis with a live birth singleton delivery between 1 July 2007 and 31 March 2018. Women with diabetes or HF before pregnancy were excluded. GDM was defined based on laboratory test results and diagnosis coding. The primary outcome was incident HF hospitalization over a period extending from the index pregnancy until 31 March 2019. The secondary outcome was prevalent peripartum cardiomyopathy at index pregnancy. Estimates of association were adjusted for relevant cardiometabolic risk factors. RESULTS: Among 906,319 eligible women (mean age 30 years SD 5.6, 50,193 with GDM 5.5%), there were 763 HF events over a median follow-up period of 7 years. GDM was associated with a higher risk of incident HF (adjusted hazard ratio aHR 1.62 95% CI 1.28, 2.05) compared with no GDM. This association remained significant after accounting for chronic kidney disease, postpartum diabetes, hypertension, and coronary artery disease (aHR 1.39 95% CI 1.09, 1.79). GDM increased the odds of peripartum cardiomyopathy (adjusted odds ratio 1.83 95% CI 1.45, 2.33). CONCLUSIONS: In a large observational study, GDM was associated with an increased risk of HF. Consequently, diabetes screening during pregnancy is suggested to identify women at risk for HF.