Class of 2010 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.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/623790 |
| Date | January 2010 |
| Creators | Perona, Stephen |
| Contributors | Ford, Marjorie, College of Pharmacy, The University of Arizona |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Electronic Report |
| Rights | Copyright © is held by the author. |
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