Impact of a Pharmacist-Managed Anticoagulation Clinic on Clinical Events

Abstract

Background:

We established an anticoagulation management service (AMS), managed by pharmacists, using a core group of physicians as consultants. Its goals were to improve patient care and to offset physician workload. The purpose of this study was to assess the impact of the AMS on hemorrhagic and thromboembolic events.

Methods:

We evaluated consecutive patients who were referred between April 2001 and December 2003 with events that included all presentations to emergency departments or hospitalizations. An adjudication committee comprising 3 physicians defined these events by using a priori-defined criteria as follows: hemorrhagic, thromboembolic, or non-anticoagulant—related. To classify the contribution of AMS staff to anticoagulant-related events, we used a 5-point Likert-type scale. The likelihood of each event having contributed to the patient's long-term disability or death was identified as not at all, somewhat, quite a lot or completely.

Results:

Over a mean of 10.1 months' follow-up, a total of 28 (13.4%) of the 209 events in 388 patients were anticoagulant-related. Of the 20 hemorrhagic events (6.1% per patient-year), AMS contribution was rated unlikely in 90%, neutral in 1 case of postoperative psoas muscle hematoma and likely in a case of hematuria. Of the 8 thromboembolic events (2.4% per patient-year), 6 (75%) were rated as an unlikely contribution, while 1 case was neutral, due to a lack of patient willingness to increase the warfarin dose that had an extension of deep venous thrombosis (DVT). The other, a patient who presented with pulmonary embolism, was rated as likely, owing to the lack of bridging with subtherapeutic INRs. The contribution of these events to long-term death or disability was rated not at all in 82%, quite a lot in 11% and completely in 7%.

Conclusion:

Overall, the AMS appeared to achieve reasonable rates of anticoagulant-related events in this patient population, evidenced by an overall event rate of 64.0% per patient-year. These data support a role for a specialized AMS to meticulously manage complicated patient populations.