Managing patients on warfarin therapy is known to be a challenging task in the outpatient setting. One of the methods used to improve warfarin therapy in the outpatient setting and increase patient compliance and time in therapeutic range (TTR) has been to refer the patient to an anticoagulation clinic. Anticoagulation clinics are used to achieve a higher TTR by using a protocol to standardize the management of warfarin therapy. This study looks into whether the implementation of a protocol to manage warfarin therapy and electronic medical records (EMR) to record the management have any effect on the patients’ TTR. 


A retrospective study was completed on patients being managed on warfarin therapy and were a part of an anticoagulation clinic. A chart review was done on ninety-one patients. All INR results were collected on the patients prior to and after the interventions were implemented and included their therapeutic range. The number of days until the INR became therapeutic and the dosage of warfarin required for patients to remain in the therapeutic range were also collected. Chi-square tests were done to analyze the data to determine whether the interventions improved patients’ TTR.


Prior to EMR implementation 62.76% of tests were found to be within therapeutic range; after EMR implementation 58.96% of tests were found to be within therapeutic range with a p-value of 0.0604. Prior to the protocol implementation, 65.41% of tests were within therapeutic range compared to 59.75% of tests within therapeutic range after protocol implementation with a p-value of 0.0409. 


Our results showed EMR implementation did not have any effect on the TTR for patients on warfarin therapy. Furthermore, when a protocol was implemented to standardize warfarin therapy and management in the anticoagulation clinic setting, study results revealed the TTR decreased with the standardized protocol with a p-value found to be statistically significant. In conclusion, the data suggests the management of warfarin therapy should be done on an individual patient case-by-case basis rather than a standardized approach to increase TTR.


No relevant conflicts of interest to declare.

Author notes


Asterisk with author names denotes non-ASH members.

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