Identification and management of noncompliance in atrial fibrillation patients receiving dabigatran: The role of a drug monitor

Background Noncompliant patients might be at risk of thromboembolism because of the short half-life and rapid offset of dabigatran etexilate. The assessment and management of dabigatran noncompliance should be optimized. Methods and Results A total of 150 nonvalvular atrial fibrillation patients receiving dabigatran were prospectively enrolled and followed for drug compliance and persistence. Noncompliance was identified by questionnaires and interviews. The hemoclot thrombin inhibitor (HTI) assay was used for monitoring the plasma dabigatran levels. Sixteen patients were noncompliant (10.7%). None of the clinical characteristics were significantly relevant to noncompliance after multivariate analysis. The dabigatran plasma level based on HTI was the only independent predictor of noncompliance (odds ratio: 0.97 per ng/mL, P = 0.003). The prothrombin time (PT), international normalized ratio of PT (INR [PT]), and activated partial thromboplastin time did not differ between compliant and noncompliant patients. During the follow-up, the persistent prescription of dabigatran was noted in 75% of noncompliant patients without improvement in compliance. The drug discontinuation rate was higher in the noncompliant than compliant patients (6.7% vs. 25%, P = 0.035). None of the patients in either group received warfarin after discontinuing dabigatran. Conclusions The assessment and management of dabigatran noncompliance is generally ignored in clinical practice. The measurement of dabigatran plasma levels by HTI could be a reliable and simple method to identify noncompliant patients.