Direct oral anticoagulant blood level monitoring in daily practice

Introduction: Routine monitoring is not required in direct oral anticoagulant (DOAC) treatment, yet it is frequently performed. Guidance on the interpretation and management of DOAC level measurements is lacking and it is key to investigate which patients would benefit from monitoring. Our aims were to investigate why DOAC levels are requested and if they lead to changes in anticoagulant management. Methods: We retrospectively collected all clinically requested DOAC levels from 2012 until 2019 in two Dutch academic hospitals. Clinical data with regard to the first DOAC level of every patient was collected by chart review. Primary outcomes were settings, indications and changes in anticoagulant management of DOAC level measurement. In addition, we compared demographic and clinical characteristics in patients with and without changes in anticoagulant management. Results: In total, we included 604 DOAC levels. The majority was requested in an outpatient setting by the department of internal medicine. In 270 (45%) cases we identified a patient specific indication, with evaluation of DOAC accumulation being the most frequently requested. Of all 604 DOAC levels, 159 (26%) were followed by changes in anticoagulation management. The large majority of changes occurred in patients that had a patient specific indication. Patients who underwent changes were older and had more comorbidity than patients who did not (n ​= ​445). Conclusion: Almost half of the DOAC levels with a specific indication for monitoring were followed by a change in anticoagulant management. Future studies should investigate the relation between DOAC levels, the changes in anticoagulant management and clinical outcomes.