The Association of Malignancy With Stroke and Bleeding in Atrial Fibrillation: A Population-Based Cohort Study.

in JACC. CardioOncology by Malak El-Rayes, Mohamed Adam, Jiming Fang, Xuesong Wang, Irene Jeong, Peter C Austin, Andrew C T Ha, Michael G Fradley, Thomas A Boyle, Eitan Amir, Paaladinesh Thavendiranathan, Husam Abdel-Qadir

TLDR

  • The study investigates the association between malignancy and stroke and bleeding risk in patients with atrial fibrillation, showing that malignancy is associated with a higher hazard of bleeding but not stroke.
  • The findings suggest that malignancy should not lower the threshold for anticoagulation in AF patients.
  • Future research is needed to explore the underlying mechanisms and individual patient characteristics.

Abstract

It is undetermined if malignancy independently increases stroke risk in atrial fibrillation (AF). This study sought to determine the association of malignancy with stroke and bleeding in AF. Population-based cohort study using administrative datasets of people aged ≥66 years with newly diagnosed AF. People diagnosed with malignancy within 5 years before AF diagnosis were matched to cancer-free control subjects on age, sex, AF diagnosis details, CHADS-VASc score, and ATRIA bleeding score. Outcomes included hospitalizations for stroke and hospitalization/emergency visits for bleeding. Cause-specific regression was used to determine the HR for malignancy after adjusting for time-varying anticoagulation status. Analyses were repeated for specific subgroups of cancer patients (with matched control subjects). Among 199,710 AF patients, 24,991 (12.5%) people had prior malignancy. Malignancy was associated with more inpatient diagnoses of AF (vs outpatient) and less anticoagulation. We matched 43,802 people with AF (21,901 with malignancy, mean age 78.1 years; 59.5% male). After adjusting for anticoagulation status, malignancy had a similar hazard of stroke (HR: 1.01; 95% CI: 0.88-1.15) but higher hazard of bleeding (HR: 1.45; 95% CI: 1.37-1.53) compared with cancer-free control subjects in the matched sample. Analyses of cancer subgroups with comparison to matched control subjects mostly showed consistent results, except for: 1) increased hazard of stroke in lung cancer; and 2) lack of increased bleeding hazard in breast cancer and lymphoma. People with AF and malignancy generally had similar hazards of stroke but higher hazards of bleeding compared with cancer-free control subjects, suggesting that malignancy should not lower the threshold for anticoagulation in AF.

Overview

  • The study aims to investigate the association between malignancy and stroke and bleeding risk in patients with atrial fibrillation (AF).
  • The study used a population-based cohort design, analyzing administrative datasets of patients aged ≥66 years with newly diagnosed AF.
  • The primary objective is to determine if malignancy independently increases stroke risk in AF, and if so, whether it should affect anticoagulation decisions.

Comparative Analysis & Findings

  • The study found that malignancy was associated with a higher hazard of bleeding (HR: 1.45; 95% CI: 1.37-1.53) compared to cancer-free control subjects.
  • However, the hazard of stroke was similar between patients with AF and malignancy compared to cancer-free control subjects (HR: 1.01; 95% CI: 0.88-1.15).
  • Analyses of specific cancer subgroups showed variations in results, with increased hazard of stroke in lung cancer and no increased bleeding hazard in breast cancer and lymphoma.

Implications and Future Directions

  • The study suggests that malignancy should not lower the threshold for anticoagulation in AF patients.
  • Further research is needed to explore the underlying mechanisms driving the differences in stroke and bleeding risk observed among various cancer subgroups.
  • The study highlights the importance of considering individual patient characteristics and cancer types when making anticoagulation decisions in patients with AF and malignancy.
Read Full Article