Clinical and safety impact of an inpatient pharmacist-directed anticoagulation service

J Hosp Med. 2011 Jul-Aug;6(6):322-8. doi: 10.1002/jhm.910.


Background: Warfarin is implicated in approximately 30% of reported anticoagulant-related errors. In order to improve anticoagulation management and safety, our institution implemented an inpatient Pharmacist-Directed Anticoagulation Service (PDAS).

Objective: To evaluate the impact of this service on both transition of care and safety of patients receiving warfarin anticoagulation.

Design: Cluster randomized trial.

Setting: Large, urban teaching hospital and level 1 trauma center.

Patients: All patients receiving warfarin on two medical and two cardiology units.

Intervention: A PDAS provided dosing, monitoring, and coordination of transition from the inpatient-to-outpatient setting.

Measurements: Endpoints were assessed during hospitalization and 30 days after discharge. Transition of care was considered effective if compliance with all of the transition of care metrics occurred. The transition of care metrics included: appropriate enrollment in the anticoagulation clinic, documented inpatient-to-outpatient provider contact, documented inpatient provider-to-anticoagulation clinic communication and patient follow-up with the anticoagulation clinic within five days of discharge. Safety was measured by the composite endpoint of thromboembolism, major bleeding, or international normalized ratio (INR) ≥5.

Results: This study included 500 patients. Transition of care metric compliance occurred in 73% more patients in the PDAS group (P < 0.001). There was also a 32% reduction in the composite safety endpoint in the PDAS group (P = 0.103). This finding was driven by a reduction in rate of INR ≥5 (P = 0.076).

Conclusions: Implementation of a PDAS provides a net improvement in quality of care for the patient taking warfarin in the inpatient setting.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Anticoagulants / therapeutic use*
  • Cluster Analysis
  • Female
  • Hospitals, Teaching
  • Hospitals, Urban
  • Humans
  • Inpatients*
  • Leadership*
  • Male
  • Medication Errors / prevention & control
  • Middle Aged
  • Patient Safety
  • Pharmacists*
  • Pharmacy Service, Hospital
  • Professional Role


  • Anticoagulants