Protocol for dabigatran follow-up and monitoring at RHJVAMC was developed by clinical and supervisory pharmacy staff, to align with national VA guidance. When a provider determines a patient is a candidate for dabigatran, an outpatient consultation is entered for the clinical pharmacy specialist to review the appropriateness of the patient selection for therapy. If the patient is eligible for therapy, the pharmacist contacts the patient to set up an initial visit to confirm selection and to provide the first dabigatran prescription and counseling. For assessments, with specific emphasis on adherence and AE monitoring, the patient is contacted 2 weeks, 1 month, 3 months, and every 6 months after the initial appointment.
Although most of the literature supports pharmacist-managed anticoagulation for patients who receive warfarin, DOACs have become more integrated into practice and more evaluated. Evidence supports pharmacists' interventions on evaluation of patient education and dosing, but there is conflicting evidence regarding pharmacists' impact on adherence after 3 months of therapy. 9,10 In a larger VA study of the impact of dabigatran adherence on patient-centered outcomes, patients were mostly nonadherent to prescribed dosing. 11 These studies support the need for improved adherence in patients prescribed DOACs and the need for further investigation of pharmacists' roles in improving patient outcomes.
Methods
This single-center, retrospective anticoagulant-use evaluation covered 2 study periods between November 1, 2011 and October 31, 2013. Study approval was obtained from the institutional review board of the Medical University of South Carolina and the research and development committee of RHJVAMC. The study population consisted of veterans who had a diagnosis of AF and received at least 3 outpatient prescription fills of a 30-day supply of dabigatran at RHJVAMC during either or both of the study periods. Patients were excluded if they were pregnant or planning to become pregnant or were incarcerated at any time during the study period. Dabigatran was selected because it was the first DOAC added to the local VA formulary before the start of this study.
Patients who met the inclusion criteria were separated into 2 groups based on the dates of their prescription fills. The precentralization group included patients treated by primary care pharmacists from November 1, 2011 to October 31, 2012; the postcentralization group included patients treated by anticoagulation clinical pharmacy specialists from November 1, 2012 to October 31, 2013. In each group, patients were followed for 1 year during their respective study period. For analysis, patients were included in both study periods if they received at least 3 fills of dabigatran during each period.
Medication possession ratio (MPR), which was used to measure the primary endpoint of adherence, is defined as the proportion of days a patient had dabigatran. The MPR denominator is the total number of days between the first and last prescription refill dates within the 52-week study period; the numerator is calculated by summing the days' supply for all but the last filling of the medication during each respective period. Nonadherence was defined as an MPR < 0.8 (or 80%), which has been used to define poor adherence in the literature. 12 The authors calculated all patients' mean MPRs and compared them to determine statistical significance by repeated-measures linear regression. Descriptive statistics on proportion of patients in each study group with MPR < 0.8 were examined. Last, the authors performed a comparative subanalysis of median MPRs to determine whether there was an adherence difference between patients initially started on dabigatran at RHJVAMC and patients who were started on dabigatran before receiving it at RHJVAMC.