Effectiveness and safety of non-vitamin-K antagonist oral anticoagulants versus warfarin in atrial fibrillation patients with thrombocytopenia

Patients with thrombocytopenia were excluded from major clinical trials that investigated non-vitamin-K antagonist oral anticoagulants (NOACs) for stroke prevention in atrial fibrillation (AF). The aim of this study was to evaluate the effectiveness and safety of NOAC versus warfarin in AF patients with thrombocytopenia. From 2010 to 2017, a cohort study based on electronic medical records of a multi-center healthcare provider in Taiwan and included 8239 anticoagulated AF patients (age 77.0 +/- 7.3years, 48.0% female). Patients were divided into two subgroups: 7872 patients with a normal platelet count and 367 patients (4.4%) with thrombocytopenia, which was defined as a platelet count less than 100x10(3)/mu L. We performed Cox proportional hazard analyses to compare the risks of ischemic stroke or systemic embolism (IS/SE), major bleeding, and death between NOAC and warfarin therapies in patients with a normal platelet count and those with thrombocytopenia, respectively. In patients with a normal platelet count, NOAC therapy (n=4904) was associated with a significantly lower risk of major bleeding, with no difference in the risk of IS/SE or death when compared with warfarin therapy (n=2968). In patients with thrombocytopenia, NOAC therapy (n=181) was associated with a lower tendency for major bleeding (aHR 0.45, 95% CI 0.16-1.14) with no significant difference in IS/SE (aHR 0.94, 95% CI 0.29-2.91) or death (aHR 0.95, 95% CI 0.46-1.95) when compared with warfarin therapy (n=186). NOAC therapy is a reasonable choice for stroke prevention in AF patients with thrombocytopenia.