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Time to Monitor Direct Oral Anticoagulants (DOACs) in Anticoagulation Clinics

Posted by gulseth.michael on September 25, 2018 at 3:45 PM

by Shelby Rabenberg, Pharm D Student Pharmacist

Edited by Michael P. Gulseth, Pharm. D., BCPS, FASHP


The scope of anticoagulation therapy is slowly changing due to the emergence of direct oral anticoagulants (DOACs). DOACs eliminate several problems that are seen with warfarin including need for frequent INR monitoring, dietary considerations and pre-operative bridging. Even though routine anticoagulation effect monitoring of DOACs is deemed as unnecessary, there are still risks that must be considered and monitored. Extended monitoring and adherence efforts are warranted with DOACs given the new problems that they present, such as drug-drug interactions, renal and hepatic dosing considerations, body weight, age and adherence. This has prompted some anticoagulation management clinics to broaden their scope to include DOAC management in addition to warfarin management.


There have been two studies conducted that demonstrate adherence patterns with the use of DOACs, specifically dabigatran. The first study was conducted to describe the relationship between adherence, pharmacist care and overall outcomes of patients that were prescribed dabigatran at a VA health facility.1 This study evaluated whether dabigatran monitoring within the first months by a pharmacist would optimize adherence and stroke outcomes in patients with atrial fibrillation. A retrospective, preimplementation-postimplementation study that monitored adherence and outcomes in dabigatran patients that were managed by anticoagulation clinic pharmacists (ACC) or received usual care. The average medication possession ratio (MPR) across each group over three months was the primary endpoint. Acceptable adherence was defined as an MPR of > 80%. Secondary endpoints included bleeding, stroke and VTE. Overall, the ACC patients were more likely to have reached the primary endpoint compared to the usual care patients (25% vs 10% p=NS). The mean MPR values were 93.1% in the ACC group and 88.3% in the usual care group, but this was not statistically significant. In regards to the secondary outcomes, none of the three events occurred in either group. Overall, this study demonstrated that VA patients treated with dabigatran that were followed by an anticoagulation clinic pharmacist did not differ from dabigatran patients receiving usual care. The patients did not differ in regards to secondary outcome events.


The second study evaluated specific modifiable site-level factors that were associated with improved dabigatran adherence.2 This study was mixed with retrospective quantitative and cross-sectional qualitative data. The study involved 67 Veterans Health Administration sites that had twenty or more patients that filled dabigatran prescriptions between 2010 and 2012 for nonvalvular atrial fibrillation. A total of 47 pharmacists from 41 sites participated in the study. Specific practices performed at each site included pharmacist guided patient education, adverse event and adherence monitoring, and appropriate patient selection. The primary outcome of this study was adherence to dabigatran. This was measured as the proportion of days covered (PDC), which is a ratio of days supplied by prescription to follow-up duration. The goal PDC was at least 80%. The results of this study showed that the median adherence proportion of dabigatran patients was about 74% with an interquartile range of 66%-88%, indicating a wide variation in proportion of adherent patients. The adherence rates across sites varied by an odds ratio of 1.57. Appropriate patient selection was performed at 31 sites, while pharmacist guided education was done at 30 sites and pharmacist monitoring was done at 28 sites. Patient selection (RR, 1.14; 95% CI, 1.05-1.25) and pharmacist guided monitoring (RR, 1.25; 95% CI, 1.11–1.41) were associated with better patient adherence. Longer duration of monitoring and collaborating with the prescriber in caring for nonadherence patients were also associated with increased adherence. Overall, the results of this study demonstrate the importance pharmacist guided management of DOACs.


Taken together, these studies appear to DOAC patient who were monitored by anticoagulation pharmacists had better adherence. Many aspects that should go into the DOAC management much like what is done with warfarin patients. Certain aspects of the clinic visits should include evaluating the risk versus benefits of anticoagulation and determining whether the use of a DOAC is appropriate, obtaining and assessing relevant baseline lab values and weight, conducting medication reconciliations, assessing and evaluating drug-drug interactions, proving patient education regarding adherence, bleeding and other specific DOAC adverse effects. In order to produce a successful monitoring clinic, there should be nine essential domains to maintain high-quality monitoring. These domains include qualified personnel, supervision, care management and coordination, documentation, patient education, patient selection and assessment, laboratory monitoring, initiation of therapy and maintenance of therapy. Because of the increasing use of DOACs, clinicians practicing in anticoagulation clinics should consider incorporating DOAC management into their practice. Engaging patients in a shared decision-making process to identify the most appropriate anticoagulant and ensuring safe long-term management are essential for high-quality, patient-centered anticoagulant care.3,4


References


1. Lee PY, Han SY, Miyahara RK. Adherence and outcomes of patients treated with dabigatran: pharmacist-managed anticoagulation clinic versus usual care. American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists. Jul 1 2013;70(13):1154-1161.

2. Shore S, Ho PM, Lambert-Kerzner A, et al. Site-level variation in and practices associated with dabigatran adherence. Jama. Apr 14 2015;313(14):1443-1450.

3. Barnes GD, Kurtz B. Direct oral anticoagulants: unique properties and practical approaches to management. Heart. Oct 15 2016;102(20):1620-1626.

4. Mohammad I, Korkis B, Garwood CL. Incorporating Comprehensive Management of Direct Oral Anticoagulants into Anticoagulation Clinics. Pharmacotherapy. Oct 2017;37(10):1284-1297.

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