Hemorrhagic Events Lead to an Increase in International Normalized Ratio in Warfarin Patients
dc.contributor.advisor | Ford, Marjorie | en |
dc.contributor.author | Perona, Stephen | |
dc.date.accessioned | 2017-06-01T20:02:18Z | |
dc.date.available | 2017-06-01T20:02:18Z | |
dc.date.issued | 2010 | |
dc.identifier.uri | http://hdl.handle.net/10150/623790 | |
dc.description | Class of 2010 Abstract | en |
dc.description.abstract | OBJECTIVES: The purpose of this study was to demonstrate that an increase in INR is associated with a hemorrhagic event in patients taking the oral anticoagulant warfarin. METHODS: A retrospective review of data from 18 patients previously stable on warfarin therapy with an elevation in INR at the time of a hemorrhagic event. Patients were receiving warfarin treatment in the anticoagulation clinic at the Southern Arizona VA Healthcare system from April 2008 to December 2009. Primary outcome measures included a comparison of INR, warfarin dose, and hematocrit at baseline, within 7 days of the event, and during follow-‐up. RESULTS: A significant increase in INR was observed from baseline to the event (2.5 +/-‐ 0.36 vs 6.2 +/-‐ 3.2; p = 0.0002) but differences in INR during all periods of follow-‐up did not differ from baseline (p = 0.35 – 0.99). When compared with baseline, differences in warfarin dose reached statistical significance when all 12 weeks of follow-‐up were included (34.4 +/-‐ 13.8 mg vs 32.4+/-‐ 15.5 mg; p = 0.01) but were not significant when only the last 8 weeks (p = 0.06) or 4 weeks (p = 0.16) were included. Hematocrit values decreased significantly following hemorrhage (39.8 +/-‐ 3.63 vs 33.5 +/-‐ 5.72; p = 0.0002) before trending toward baseline (39.85 +/-‐ 3.63 vs 37.13 +/-‐ 4.72; p = 0.007). CONCLUSIONS: Hemorrhagic events were associated with an increased INR in previously stable warfarin patients. The mean weekly warfarin dose required to maintain a therapeutic INR returned to baseline within 8 weeks of the hemorrhagic event. | |
dc.language.iso | en_US | en |
dc.publisher | The University of Arizona. | en |
dc.rights | Copyright © is held by the author. | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | |
dc.subject | International Normalized Ratio | en |
dc.subject | Hemorrhagic Events | en |
dc.subject | Warfarin | en |
dc.subject.mesh | International Normalized Ratio | en |
dc.subject.mesh | Hemorrhage | en |
dc.subject.mesh | Anticoagulants | en |
dc.subject.mesh | Warfarin | en |
dc.title | Hemorrhagic Events Lead to an Increase in International Normalized Ratio in Warfarin Patients | en_US |
dc.type | text | en |
dc.type | Electronic Report | en |
dc.contributor.department | College of Pharmacy, The University of Arizona | en |
dc.description.collectioninformation | This item is part of the Pharmacy Student Research Projects collection, made available by the College of Pharmacy and the University Libraries at the University of Arizona. For more information about items in this collection, please contact Jennifer Martin, Librarian and Clinical Instructor, Pharmacy Practice and Science, jenmartin@email.arizona.edu. | en |
html.description.abstract | OBJECTIVES: The purpose of this study was to demonstrate that an increase in INR is associated with a hemorrhagic event in patients taking the oral anticoagulant warfarin. METHODS: A retrospective review of data from 18 patients previously stable on warfarin therapy with an elevation in INR at the time of a hemorrhagic event. Patients were receiving warfarin treatment in the anticoagulation clinic at the Southern Arizona VA Healthcare system from April 2008 to December 2009. Primary outcome measures included a comparison of INR, warfarin dose, and hematocrit at baseline, within 7 days of the event, and during follow-‐up. RESULTS: A significant increase in INR was observed from baseline to the event (2.5 +/-‐ 0.36 vs 6.2 +/-‐ 3.2; p = 0.0002) but differences in INR during all periods of follow-‐up did not differ from baseline (p = 0.35 – 0.99). When compared with baseline, differences in warfarin dose reached statistical significance when all 12 weeks of follow-‐up were included (34.4 +/-‐ 13.8 mg vs 32.4+/-‐ 15.5 mg; p = 0.01) but were not significant when only the last 8 weeks (p = 0.06) or 4 weeks (p = 0.16) were included. Hematocrit values decreased significantly following hemorrhage (39.8 +/-‐ 3.63 vs 33.5 +/-‐ 5.72; p = 0.0002) before trending toward baseline (39.85 +/-‐ 3.63 vs 37.13 +/-‐ 4.72; p = 0.007). CONCLUSIONS: Hemorrhagic events were associated with an increased INR in previously stable warfarin patients. The mean weekly warfarin dose required to maintain a therapeutic INR returned to baseline within 8 weeks of the hemorrhagic event. |