Independent data about the safety and efficacy of rivaroxaban for prevention of stroke/embolism are needed: Author reply

We appreciate the comments of Stollberger et al .1 regarding our publication on the persistence with rivaroxaban therapy in the Dresden NOAC registry.2 A number of issues were addressed in their letter, some of which are directly related to our publication while others are more related to an overall concern regarding the safety of non-VKA oral anticoagulants (NOACs) such as rivaroxaban. Unfortunately, word count restrictions do not allow discussing the latter issues in detail here, especially since some of these issues were discussed with Stollberger et al. previously.3,4 More or less directly related to our manuscript are the following questions: ‘ How did the authors ascertain that the patients were indeed taking the drug? Whereas adherence to VKA is easily monitored by measuring the international normalized ratio (INR), a readily available test for rivaroxaban effect is not available. Were serum concentrations of rivaroxaban obtained among the participants of the registry? ’ First of all, Stollberger et al. need to understand that our publication related to persistence (=the …