Evaluation of Differences in Percentage of International Normalized Ratios in Range Between Pharmacist-Led and Physician-Led Anticoagulation Management Services

Abstract

Background: The safety and efficacy of warfarin depend on maintaining the international normalized ratio (INR) in an established range. Objective: The purpose was to determine whether a coordinated pharmacist-led approach improved percentage of INRs in therapeutic range in comparison to a physician-led anticoagulation management service (AMS). Methods: A retrospective chart review was conducted for patients at a multisite primary care organization. INR data for patients receiving warfarin management by a physician were collected from December 1, 2009 to May 31, 2010. These were compared to INR results from December 1, 2010 to May 31, 2011, during which patients received warfarin management from a pharmacist. The primary end points were percentage of INRs within a goal range of 2.0 to 3.0 and an expanded goal range of 1.8 to 3.2 for the physician-led group versus the pharmacist-led group. Results: The percentage of INR results within the goal range (2.0-3.0) was greater among patients in the pharmacist-led group (n = .130) than the physician-led group (n = 96; 57.5% vs 50.0%, respectively; P = .0004). The percentage of INR results <1.5 (7.3% vs 5.1%) and >3.5 (11.4% vs 7.1%) was also statistically significant in favor of the pharmacist-led AMS, with P values of .03 and .0004, respectively. Conclusion: A pharmacist-led AMS improved the percentage of INRs in range, with significantly less out-of-range results.