Using highly variable warfarin dosing to identify patients at risk for adverse events
<p>Abstract</p> <p>Background</p> <p>Patients who receive highly variable doses of warfarin may be at risk for poor anticoagulation control and adverse events. However, we lack a system to identify patients with the highest dose variability. Our objectives were to devel...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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BMC
2011-10-01
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| Series: | Thrombosis Journal |
| Subjects: | |
| Online Access: | http://www.thrombosisjournal.com/content/9/1/14 |
| _version_ | 1818472940025413632 |
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| author | Henault Lori E Ozonoff Al Evans Mary Marrast Lyndonna Rose Adam J |
| author_facet | Henault Lori E Ozonoff Al Evans Mary Marrast Lyndonna Rose Adam J |
| author_sort | Henault Lori E |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Patients who receive highly variable doses of warfarin may be at risk for poor anticoagulation control and adverse events. However, we lack a system to identify patients with the highest dose variability. Our objectives were to develop a scoring system to identify patients with high dose variability, and to validate this new measure by demonstrating that patients so identified have poor anticoagulation control and higher rates of adverse events (criterion validity).</p> <p>Methods</p> <p>We used a database of over 4, 000 patients who received oral anticoagulation in community practice between 2000-2002. We reviewed the charts of 168 patients with large warfarin dose variation and agreed on 18 risk factor definitions for high dose variability. We identified 109 patients with the highest dose variability (cases), as measured by coefficient of variation (CoV, SD/mean). We matched each case to two controls with low dose variability. Then, we examined all 327 charts, blinded to case/control status, to identify the presence or absence of the 18 risk factors for dose variability. We performed a multivariable analysis to identify independent predictors of high CoV. We also compared anticoagulation control, as measured by percent time in therapeutic range (TTR), and rates of adverse events between groups.</p> <p>Results</p> <p>CoV corresponded with other measures of anticoagulation control. TTR was 53% among cases and 79% among controls (p < 0.001). CoV also predicted adverse events. Six cases experienced a major hemorrhage versus 1 control (p < 0.001) and 3 cases had a thromboembolic event versus 0 control patients (p = 0.04). Independent predictors of high dose variability included hospitalization (OR = 21.3), decreased oral intake (OR = 12.2), use of systemic steroids (OR = 6.1), acetaminophen (OR = 4.0) and antibiotics (OR = 2.7; p < 0.05 for all).</p> <p>Conclusion</p> <p>CoV can be used to identify patients at risk for poor anticoagulation control and adverse events. This new measure has the potential to identify patients at high risk before they suffer adverse events.</p> |
| first_indexed | 2024-04-14T04:15:46Z |
| format | Article |
| id | doaj.art-dfb63bfafbe54bbb9112dda6ed863c14 |
| institution | Directory Open Access Journal |
| issn | 1477-9560 |
| language | English |
| last_indexed | 2024-04-14T04:15:46Z |
| publishDate | 2011-10-01 |
| publisher | BMC |
| record_format | Article |
| series | Thrombosis Journal |
| spelling | doaj.art-dfb63bfafbe54bbb9112dda6ed863c142022-12-22T02:12:55ZengBMCThrombosis Journal1477-95602011-10-01911410.1186/1477-9560-9-14Using highly variable warfarin dosing to identify patients at risk for adverse eventsHenault Lori EOzonoff AlEvans MaryMarrast LyndonnaRose Adam J<p>Abstract</p> <p>Background</p> <p>Patients who receive highly variable doses of warfarin may be at risk for poor anticoagulation control and adverse events. However, we lack a system to identify patients with the highest dose variability. Our objectives were to develop a scoring system to identify patients with high dose variability, and to validate this new measure by demonstrating that patients so identified have poor anticoagulation control and higher rates of adverse events (criterion validity).</p> <p>Methods</p> <p>We used a database of over 4, 000 patients who received oral anticoagulation in community practice between 2000-2002. We reviewed the charts of 168 patients with large warfarin dose variation and agreed on 18 risk factor definitions for high dose variability. We identified 109 patients with the highest dose variability (cases), as measured by coefficient of variation (CoV, SD/mean). We matched each case to two controls with low dose variability. Then, we examined all 327 charts, blinded to case/control status, to identify the presence or absence of the 18 risk factors for dose variability. We performed a multivariable analysis to identify independent predictors of high CoV. We also compared anticoagulation control, as measured by percent time in therapeutic range (TTR), and rates of adverse events between groups.</p> <p>Results</p> <p>CoV corresponded with other measures of anticoagulation control. TTR was 53% among cases and 79% among controls (p < 0.001). CoV also predicted adverse events. Six cases experienced a major hemorrhage versus 1 control (p < 0.001) and 3 cases had a thromboembolic event versus 0 control patients (p = 0.04). Independent predictors of high dose variability included hospitalization (OR = 21.3), decreased oral intake (OR = 12.2), use of systemic steroids (OR = 6.1), acetaminophen (OR = 4.0) and antibiotics (OR = 2.7; p < 0.05 for all).</p> <p>Conclusion</p> <p>CoV can be used to identify patients at risk for poor anticoagulation control and adverse events. This new measure has the potential to identify patients at high risk before they suffer adverse events.</p>http://www.thrombosisjournal.com/content/9/1/14anticoagulantsdose variabilitymedication therapy managementrisk factorswarfarin. |
| spellingShingle | Henault Lori E Ozonoff Al Evans Mary Marrast Lyndonna Rose Adam J Using highly variable warfarin dosing to identify patients at risk for adverse events Thrombosis Journal anticoagulants dose variability medication therapy management risk factors warfarin. |
| title | Using highly variable warfarin dosing to identify patients at risk for adverse events |
| title_full | Using highly variable warfarin dosing to identify patients at risk for adverse events |
| title_fullStr | Using highly variable warfarin dosing to identify patients at risk for adverse events |
| title_full_unstemmed | Using highly variable warfarin dosing to identify patients at risk for adverse events |
| title_short | Using highly variable warfarin dosing to identify patients at risk for adverse events |
| title_sort | using highly variable warfarin dosing to identify patients at risk for adverse events |
| topic | anticoagulants dose variability medication therapy management risk factors warfarin. |
| url | http://www.thrombosisjournal.com/content/9/1/14 |
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