Endometriosis and long-term cardiovascular risk: a nationwide Danish study

BACKGROUND AND AIMS: Endometriosis, a systemic gynecological disease affecting 10% of women in reproductive age, shares pathophysiological characteristics with cardiovascular disease. However, data on the relationship between endometriosis and cardiovascular outcomes are scarce, prompting this study to address the knowledge-gap. METHODS: Using Danish nationwide registries, women diagnosed with endometriosis (1977-2021) were identified and matched with controls in a 1:4 ratio based on year of birth. The primary outcome was a composite of acute myocardial infarction and ischemic stroke. The secondary outcomes were arrhythmias, heart failure, and mortality. RESULTS: In total, 60,508 women with endometriosis and 242,032 matched controls were included (median age 37.3 years). Women with endometriosis were more comorbid and used more medications than controls. The incidence rates of the composite outcomes were 3.2 (95% confidence interval CI 3.2-3.3) and 2.7 (95% CI 2.7-2.8) per 1000 person-years among women with and without endometriosis, respectively. Women with endometriosis had a significantly higher associated rate of the composite outcome compared with controls (unadjusted hazard ratio HR 1.18 95% CI 1.14-1.23, adjusted HR 1.15 95% CI 1.11-1.20). Likewise, women with endometriosis were also at significantly increased associated risk of arrhythmias (unadjusted HR 1.24 95% CI 1.20-1.28, adjusted HR 1.21 95% CI 1.17-1.25) and heart failure (unadjusted HR 1.16 95% CI 1.09-1.22, adjusted HR 1.11 95% CI 1.05-1.18) but at decreased risk of mortality (unadjusted HR 0.95 95% CI 0.92-0.97, adjusted HR 0.93 95% CI 0.91-0.96). CONCLUSIONS: Women with endometriosis have a higher associated long-term risk of cardiovascular outcomes compared with controls. Despite subtle absolute risk-differences, the high prevalence of endometriosis underscores the importance of these findings.