Heart failure (HF) patients diagnosed with breast cancer (BC) may have a higher risk of death, and different HFpresentation and treatment than patients without BC.

Methods and results:A total of 14 998 women with incident HF (iHF) or prevalent HF (pHF) enrolled in the Swedish HF Registrywithin and after 1 month since HF diagnosis, respectively, between 2008 and 2013. Patients were linked withthe National Patient-, Cancer-, and Cause-of-Death Registry. Two hundred and ninety-four iHF and 338 pHFpatients with BC were age-matched to 1470 iHF and 1690 pHF patients without BC. Comorbidity and treatmentcharacteristics were compared using the v2 tests for categories. Cox proportional hazard models assessedthe hazard ratio (HR) and 95% confidence intervals (95% CIs) of all-cause and cardiovascular mortality amongHF patients with and without BC. In the pHF group, BC patients had less often myocardial infarction (21.6% vs.28.6%, P < 0.01) and received less often aspirin (47.6% vs. 55.1%, P = 0.01), coronary revascularization (11.8% vs.16.2%, P < 0.01), or device therapy (0.9% vs. 3.0%, P = 0.03). After median follow-up of 2 years, risk of all-causemortality (iHF: HR = 1.04, 95% CI = 0.83–1.29 and pHF: HR = 0.94, 95% CI = 0.79–1.12), cardiovascular mortality(iHF: HR = 0.94, 95% CI = 0.71–1.24 and pHF: HR = 0.89, 95% CI = 0.71–1.10), and HF mortality (iHF: HR = 0.80,95% CI = 0.34–1.90 and pHF: HR = 0.75, 95% CI = 0.43–1.29) were similar for patients with and without BC inthe iHF and pHF groups.

Conclusion: Risk of all-cause and cardiovascular mortality in HF patients did not differ by BC status. Differences in pre-existingmyocardial infarction and HF treatment among pHF patients with and without BC may suggest differences in pathogenesis of HF.