Download Full Text (579 KB)

Document Type





Warfarin, an oral anticoagulant, is a “high-risk” medication with narrow therapeutic range and risks for serious complications if not carefully managed. Therapeutic effect is determined using a blood test called the International Normalized Ratio (INR). Evidence shows a higher percentage of Time in Therapeutic Range (TTR) decreases the risk of adverse events including bleeding, hemorrhagic stroke, and death. An optimal TTR is 60 – 70% or higher. Improving TTR by 2.5 - 5% could significantly impact outcomes.

It was hypothesized that an algorithm based approach to Warfarin management by a consistent team of RN’s would improve TTR and outcomes.

To test this, TTR for a group of patients enrolled in an RN Managed Anticoagulation Program was compared with TTR for two groups of non-enrolled patients. The RNs received training on warfarin management and application of the dosing algorithm, providers placed orders to enroll patients in the RN Managed Program and TTR was monitored post-enrollment.

The results showed an overall improvement in TTR in both groups.

Group One: Pre-enrollment Q4 2018 Average TTR = 59.07%, Enrollment Q1 & Q2 2019, Post-enrollment Q3 2019 through Q2 2020 Average TTR = 65.58% - an increase of 6.51%

Group Two: Pre-enrollment Q1 2019 Average TTR = 57.47%, Enrollment Q2 & Q3 2019, Post-enrollment Q4 2019 through Q2 2020 Average TTR = 67.47% - an increase of 10%

It is concluded that a systematic, algorithm based approach to warfarin management by a consistent team of RNs significantly improved TTR and improved outcomes for these patients.

Publication Date



Beth Ormsby, MS RN IV; Stacee Marvin, RN; Viktoria Leblanc, BS, RN IV; Ashley Harris, RN III

Rochester Regional Health, Ambulatory Care

RN Managed Warfarin Therapy Improves Patient Outcomes