Background: Recent studies have shown that patients with endometriosis have an increased risk of coronary artery disease. Inflammatory diseases that increase the risk of coronary artery disease have also been shown to worsen outcomes. We sought to evaluate the effect of co-occurring endometriosis among women with myocardial infarction (MI) on stroke, length of stay (LOS) and in-hospital mortality.

Methods: Data was obtained from the Healthcare Cost and Utilization Project’s Nationwide Inpatient Sample (NIS). We studied women ages 18 and above hospitalized for MI between 2007 and 2011. Admissions for endometriosis, MI and outcomes data were extracted using ICD-9 CM codes. We estimated weighted frequencies and proportions for all patients admitted for MI, co-occurring endometriosis and for all covariates. We then performed bivariate parametric tests of association as appropriate. In order to evaluate the independent effect of co-occurring endometriosis and MI on stroke, LOS and in-hospital mortality, we constructed multivariate regression models.

Results: We found a total of 420,940 hospital admissions for myocardial infarction. Out of these, 80 had co-occurring endometriosis. Women with these co-occurring conditions were more likely to be white (67.5%) and privately insured (53.8%). In adjusted models, compared to those without, women with co-occurring endometriosis and MI did not have a significantly higher risk of stroke (aOR=1.10, 95% CI: 0.27- 4.56) or prolonged LOS (aOR=1.29, 95% CI: 0.45 - 3.04). Risk was not found to be increased for in-hospital mortality (aOR=0.71, 95% CI: 0.26 - 1.95).

Conclusion: Our study shows that co-occurring endometriosis among women with MI was not significantly associated with worse in-hospital outcomes. Larger, prospective, studies with longer follow-up time after discharge are needed to further evaluate this association.