Direct Oral Anticoagulants in Atrial Fibrillation Patients With Concomitant Hyperthyroidism

OBJECTIVE: Patients with hyperthyroidism were excluded from the randomized clinical trials of direct oral anticoagulants (DOACs) for stroke prevention in patients with nonvalvular atrial fibrillation (NVAF). METHODS: We performed a nationwide retrospective cohort study using data from the Taiwan National Health Insurance Research Database. We enrolled 3213 and 1181 NVAF patients with hyperthyroidism who were taking DOACs and warfarin, respectively, from June 1, 2012 to December 31, 2017. We also enrolled 53 591 and 16 564 NVAF patients without hyperthyroidism, taking DOACs and warfarin, respectively. We used propensity score stabilized weights (PSSWs) to balance covariates across the study groups. We also used 1:4 matching on both taking DOACs, with (n = 3213) and without hyperthyroidism (n = 12 852); and both taking warfarin, with (n = 1181) and without hyperthyroidism (n = 4724). RESULTS: After PSSW, DOAC had a comparable risk of ischemic stroke/systemic embolism (IS/SE) and a lower risk of major bleeding (hazard ratio HR 0.65; 95% confidential interval CI, 0.44-0.96; P = 0.0295) than warfarin among patients with hyperthyroidism. There were comparable risks of IS/SE and major bleeding between those patients with and without hyperthyroidism. However, among patients taking warfarin, those with hyperthyroidism had a lower risk of IS/SE than those without hyperthyroidism (HR 0.61; 95% CI, 0.43-0.86; P = 0.0050). CONCLUSION: Among NVAF Asian patients with concomitant hyperthyroidism, DOACs may be an effective and safer alternative to warfarin. Thromboprophylaxis with DOACs may be considered for such patients, and it is important to validate this finding in further prospective study.