Date of Award


Degree Type

Evidence-Based Project Report

Degree Name

Doctor of Nursing Practice (DNP)



First Advisor

Theresa A. Kessler


It is estimated that three million people in the United States are on oral anticoagulation therapy (warfarin). Populations studied have been found in therapeutic range 64% of the time (Pernod, Labarere, & Bosson, 2008). The low percentage of therapeutic range is attributable to (a) adherence, (b) monitoring infrequency, (c) Vitamin K antagonists, and (d) the effects of aging and comorbidities. The purpose of this evidence-based practice (EBP) project was to examine whether an educational intervention would improve the knowledge of patients receiving warfarin therapy. Roy’s model for patient adaptation and the Stetler Model for EBP were used as frameworks for the project. A pretest/posttest design was used over a 2-week period that included 38 patients aged 42 through 90 (M = 74.7, SD = 10.1). An educational intervention done by the project manager using a booklet, video, and food models on warfarin therapy was completed after the pretest. Patients’ INR (International Normalized Ratio) values were tracked at pretest, posttest, and every two weeks for twelve weeks. A paired sample t test found a statistically significant difference between the pre- and posttest scores. The mean pretest score was 11.11; SD = 2.35 compared to the posttest mean score of 12.48; SD = 1.45; (t (37) = - 4.215, p < .001). No significant difference from pretest INR to posttest INR was found (t (26) = -2.002, p > .056). A Cochran’s Q test showed INR results from 4 to 12 weeks were not statistically significant (x²(4) = 4, p > .406). Results demonstrated that an educational intervention improved patient knowledge, but the intervention did not improve the patients’ INR values over two weeks, or over the four to 12 week time frame. There were no trends over time, other than to support the literature of a low percentage of the population in therapeutic range. Replication of this EBP project has been patterned by the project manager’s institution.