Women who were diagnosed with breast cancer were associated with increased risk for atrial fibrillation (AF) and, in the setting of breast cancer, AF was associated with increased cardiovascular (CV) mortality at 1 year. These findings were presented during the American Heart Association (AHA) Scientific Sessions, held virtually from November 13 to 15, 2021.

The relationship between breast cancer and AF remains poorly understood. In order to better assess this relationship, researchers examined the Surveillance, Epidemiology, and End Results-Medicare database for women aged 66 years or more with a new, primary diagnosis of breast cancer between 2007 and 2014. A control cohort of women without breast cancer were propensity matched 1:1. Researchers also assessed the 1-year incidence of AF and CV mortality.

A total of 85,423 women with breast cancer were identified, among whom 11.0% were diagnosed with AF prior to being diagnosed with breast cancer (incidence rate, 3.3%; 95% CI, 3.0%-3.5%).


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AF diagnoses tended to occur during the first 2 months after a breast cancer diagnosis at a monthly rate of 0.6%.

Stratified by subgroups, AF occurred more often among Black women than White women (58.8 vs 49.9 per 1000 person-years [py] in 2014). Compared with American Joint Committee on Cancer (AJCC) stage I, risk was increased among stage II (adjusted hazard ratio [aHR], 1.51; 95% CI, 1.37-1.65), stage III (aHR, 2.63; 95% CI, 2.35-2.94), and stage IV (aHR, 4.21; 95% CI, 4.04-5.48).

Both women who had AF prior to breast cancer diagnosis (aHR, 1.70; 95% CI, 1.26-2.29) and were diagnosed after having cancer (aHR, 3.51; 95% CI, 1.69-7.32) were at increased risk for 1-year CV mortality compared with the control cohort.

These data suggested that breast cancer increased risk for AF and that AF associated with elevated CV mortality among the breast cancer population. The incidence of AF was positively related with breast cancer stage.

This study was limited by its retrospective design, and these findings should be confirmed among an independent cohort.

Disclosure: Multiple authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.

Reference

Guha A, Fradley M, Dent SF, et al. Atrial fibrillation in breast cancer patients: incidence, prevalence, risk factors, and mortality: longitudinal Seer-Medicare analysis. Presented at: AHA Scientific Sessions 2021. Abstract 184.