S Johnson1. 1. Clinical Pharmacy Services, Rock Creek Medical Center, Kaiser Permanente Colorado, Denver, CO, USA. samuel.g.johnson@kp.org
Abstract
BACKGROUND: Use of antiplatelet therapy in combination with oral anticoagulants remains controversial. The purpose of this article is to review current consensus recommendations for antithrombotic therapy, to evaluate risks for bleeding among patients taking combination antithrombotic therapy, and lastly to review single-center data from Kaiser Permanente Colorado detailing clinical outcomes associated with combination therapy. METHODS: This was a retrospective, longitudinal pharmacoepidemiologic review. Adult patients receiving warfarin managed by a clinical pharmacy service who had documented antiplatelet (aspirin, clopidogrel, and/or dipyridamole) use (combination therapy cohort) or non-use (monotherapy cohort) were identified as of September 30, 2005. Utilizing integrated, electronic medical records, anticoagulation-related adverse events (death, hemorrhage, thrombosis) and coronary events were identified during a six-month follow-up (October 2005 through March 2006). Proportions of events were compared between cohorts. Independent associations between the cohorts and the outcomes were assessed with adjustment for potential confounding factors. RESULTS: Data from 2,560 monotherapy and 1,623 combination therapy patients were analyzed. Patients in the combination therapy cohort were more likely to have had anticoagulation-related hemorrhages (4.2% vs. 2.0%, unadjusted p<0.001). With adjustment, combined warfarin and antiplatelet use was independently associated with hemorrhagic (OR=2.75; 95% CI 1.44, 5.28) but not coronary (OR=0.99; 95% CI 0.37, 2.62) events. CONCLUSIONS: At the population level, the hemorrhagic risk associated with warfarin therapy combined with antiplatelet therapy appears to outweigh the benefits. These findings suggest that clinicians carefully consider risks and benefits when prescribing antiplatelet therapy for patients taking warfarin who do not meet evidence-based criteria for that approach.
BACKGROUND: Use of antiplatelet therapy in combination with oral anticoagulants remains controversial. The purpose of this article is to review current consensus recommendations for antithrombotic therapy, to evaluate risks for bleeding among patients taking combination antithrombotic therapy, and lastly to review single-center data from Kaiser Permanente Colorado detailing clinical outcomes associated with combination therapy. METHODS: This was a retrospective, longitudinal pharmacoepidemiologic review. Adult patients receiving warfarin managed by a clinical pharmacy service who had documented antiplatelet (aspirin, clopidogrel, and/or dipyridamole) use (combination therapy cohort) or non-use (monotherapy cohort) were identified as of September 30, 2005. Utilizing integrated, electronic medical records, anticoagulation-related adverse events (death, hemorrhage, thrombosis) and coronary events were identified during a six-month follow-up (October 2005 through March 2006). Proportions of events were compared between cohorts. Independent associations between the cohorts and the outcomes were assessed with adjustment for potential confounding factors. RESULTS: Data from 2,560 monotherapy and 1,623 combination therapy patients were analyzed. Patients in the combination therapy cohort were more likely to have had anticoagulation-related hemorrhages (4.2% vs. 2.0%, unadjusted p<0.001). With adjustment, combined warfarin and antiplatelet use was independently associated with hemorrhagic (OR=2.75; 95% CI 1.44, 5.28) but not coronary (OR=0.99; 95% CI 0.37, 2.62) events. CONCLUSIONS: At the population level, the hemorrhagic risk associated with warfarin therapy combined with antiplatelet therapy appears to outweigh the benefits. These findings suggest that clinicians carefully consider risks and benefits when prescribing antiplatelet therapy for patients taking warfarin who do not meet evidence-based criteria for that approach.
Authors: Jonatas Zeni Klafke; Mariane Arnoldi da Silva; Mateus Fortes Rossato; Gabriela Trevisan; Cristiani Isabel Banderó Walker; Cláudio Alberto Martins Leal; Diego Olschowsky Borges; Maria Rosa Chitolina Schetinger; Rafael Noal Moresco; Marta Maria Medeiros Frescura Duarte; Adair Roberto Soares Dos Santos; Paulo Ricardo Nazário Viecili; Juliano Ferreira Journal: Evid Based Complement Alternat Med Date: 2011-09-07 Impact factor: 2.629
Authors: Jun Ho Kim; Jaemin Lee; Soouk Kang; Hongsik Moon; Kyung Ho Chung; Kyoung Rak Kim Journal: Biomol Ther (Seoul) Date: 2016-11-01 Impact factor: 4.634