Background: Atrial fibrillation (AF) is associated with an increased
risk of heart failure, death and thromboembolism. AF is prevalent in patients
with cancer. Although current guidelines suggest the application of oral
anticoagulants (OACs) for thromboembolic event prevention in high-risk AF
patients, owing to the high thromboembolic and bleeding risks of active-cancer
patients, there is no consensus on the use of OACs in such a population.
Therefore, we conducted this retrospective cohort study to investigate the
applicability of the CHADS-VASc score and to evaluate the efficacy
and safety outcomes of OAC therapy in active-cancer patients with AF.
Methods: This retrospective cohort study enrolled patients diagnosed
with cancer at National Cheng Kung University Hospital between November 2012 and
August 2019. The primary outcomes included all-cause mortality, thromboembolic
events (stroke/transient ischemic attack and systemic emboli), acute myocardial
infarction (AMI), hospitalization for HF and major bleeding events.
Results: We enrolled 2429 patients with active cancer. Among these
patients, 1060 patients (43.6%) had AF. After 1:2 propensity score matching, 690
cancer patients with AF were enrolled for the final analysis, grouped as follows:
225 patients taking OACs and 465 patients without OAC treatment. The OAC-treated
group had lower all-cause mortality than the patients without OAC treatment
(all-cause mortality rate in OAC treatment vs. non-OAC treatment: 24.4%
vs. 37.4%, hazard ratio 0.58 [95% confidence interval (CI)
0.43–0.78], p 0.001). However, there was no difference in
thromboembolic events, myocardial infarction or heart failure hospitalization
between the OAC-treated and non-OAC-treated groups. Importantly, the risk of
major bleeding composition (i.e., major gastrointestinal bleeding and
intracranial hemorrhage) was similar between these two groups. Moreover, the
CHADS-VASc score could not predict thromboembolic events in the
enrolled active-cancer patients with AF (OR 1.23, 95% CI 0.98–1.56).
Conclusions: OAC treatment may significantly reduce the risk of death,
without safety concerns, in active-cancer patients with AF. OAC treatment may not
prevent thromboembolic events in patients with active cancer and AF. However, we
found that OAC treatment is associated with improved prognosis without increasing
the risks of major bleeding, despite several limitations in this study. Further
studies are required to determine the optimal use of anticoagulation therapy in
this high-risk population.