Bleeding complications in oral anticoagulant therapy. An analysis of risk factors

Meer, F. J. M. Van Der; Rosendaal, F.R.; Vandenbroucke, Jan P.; Briët, E.

doi:10.1001/archinte.153.13.1557

Cited by 354 publications

(261 citation statements)

References 21 publications

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Section: Discussionmentioning

confidence: 99%

“…20 Prior studies have also provided conflicting data on whether older age is a risk factor for warfarin-associated hemorrhage. 3,[6][7][8]21,22 Advantages of the current study include a considerably higher number of outcome events, more person-years of observation accumulated in the oldest patients, and separate analyses between intracranial and extracranial hemorrhages.The relationship between age and hemorrhage risk was found to be somewhat attenuated after adjustment for other medical conditions, suggesting that clinical factors related to aging mediate some of the higher risk. That an independent relationship still remained after multivariable adjustment indicates that other age-related features contribute to hemorrhage risk and were not identified in this study.…”

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confidence: 99%

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Age and the Risk of Warfarin‐Associated Hemorrhage: The Anticoagulation and Risk Factors In Atrial Fibrillation Study

Fang

Hylek

et al. 2006

J American Geriatrics Society

387

409

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OBJECTIVES-To assess whether older age is independently associated with hemorrhage risk in patients with atrial fibrillation, whether or not they are taking warfarin therapy. DESIGN-Cohort study.SETTING-Integrated healthcare delivery system. PARTICIPANTS-Thirteen thousand five hundred fifty-nine adults with nonvalvular atrial fibrillation.MEASUREMENTS-Patient data were collected from automated clinical and administrative databases using previously validated search algorithms. Medical charts were reviewed from patients hospitalized were for major hemorrhage (intracranial, fatal, requiring ≥2 units of transfused blood, or involving a critical anatomic site). Age was categorized into four categories (<60, 60-69, 70-79, and ≥80), and multivariable Poisson regression was used to assess whether major hemorrhage rates increased with age, stratified by warfarin use and adjusted for other clinical risk factors for hemorrhage.RESULTS-A total of 170 major hemorrhages were identified during 15,300 person-years of warfarin therapy and 162 major hemorrhages during 15,530 person-years off warfarin therapy. Hemorrhage rates rose with older age, with an average increase in hemorrhage rate of 1.2 (95% confidence interval (CI) 1.0-1.4) per older age category in patients taking warfarin and 1.5 (95% CI=1.3-1.8) in those not taking warfarin. Intracranial hemorrhage rates were significantly higher in those aged 80 and older (adjusted rate ratio=1.8, 95% CI=1.1-3.1 for those taking warfarin, adjusted rate ratio=4.7, 95% CI=2.4-9.2 for those not taking warfarin) than in those younger than 80. Author Contributions: Margaret Fang, Alan Go, Elaine Hylek, and Daniel Singer contributed to study concept and design, data analysis and interpretation, and preparation of manuscript. Yuchiao Chang contributed to data analysis and interpretation, and preparation of manuscript. Lori Henault and Nancy Jensvold contributed to study concept and design and acquisition of subjects and data. Anticoagulation therapy with warfarin effectively reduces the risk of ischemic stroke associated with atrial fibrillation but also increases the risk for major hemorrhage. [1][2][3][4] Although previous randomized trials of warfarin for atrial fibrillation reported low rates of hemorrhage, these studies included few patients aged 80 and older and selected their patients more rigorously than in actual clinical practice. 1,5 It is uncertain whether the low bleeding rates observed in trial settings apply to patients with atrial fibrillation in usual clinical care. Prior studies have also provided conflicting evidence as to whether older age is an independent risk factor for warfarin-associated hemorrhage. 6-8 As increasing numbers of elderly patients take warfarin for atrial fibrillation, 9 more-precise data are needed on hemorrhage rates in the oldest patients. NIH Public AccessMost observational studies of warfarin did not specifically address the risk of hemorrhage in patients with atrial fibrillation. Studies generally included patients taking warfarin for m...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Age and the Risk of Warfarin‐Associated Hemorrhage: The Anticoagulation and Risk Factors In Atrial Fibrillation Study

Fang

Hylek

et al. 2006

J American Geriatrics Society

387

409

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“…Resultados similares foram encontrados por Poli et al 17 , estudando um número maior de pacientes. Trabalhos antigos da literatura já indicavam essa falta de relação entre sangramento e sexo [49][50][51] ; outros, entretanto, indicam uma freqüência maior de hemorragias nas mulheres em uso dos AVK 37,52 .…”

Section: Discussionunclassified

Complicações da terapia anticoagulante com warfarina em pacientes com doença vascular periférica: estudo coorte prospectivo

et al. 2006

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194 ResumoObjetivo: Estudar prospectivamente a freqüência de complicações em pacientes tratados com warfarina e acompanhados no Ambulatório de Anticoagulação da Faculdade de Medicina de Botucatu da Universidade Estadual Paulista.Métodos: Pacientes sorteados entre os agendados para consulta de junho de 2002 a fevereiro de 2004. Na primeira consulta, foi preenchida ficha com dados de identificação e clínicos. A cada retorno, ou quando o paciente procurou o hospital por intercorrência, foi preenchida ficha com a razão normatizada internacional, existência e tipo de intercorrência e condições de uso dos antagonistas da vitamina K.Resultados: Foram acompanhados 136 pacientes (61 homens e 75 mulheres), 99 com tromboembolismo venoso e 37 com doença arterial; 59 pacientes eram de Botucatu, e 77, de outros municípios. Foram registradas 30 intercorrências: nove não relacionadas ao uso da warfarina e 21 complicações hemorrágicas (38,8 por 100 pacientes/ ano). Uma hematêmese foi considerada grave (1,9 por 100 pacientes/ ano). As demais foram consideradas moderadas ou leves. Não houve óbitos, hemorragia intracraniana ou necrose cutânea. A única associação significante foi da freqüência de hemorragia com nível médio de razão normatizada internacional.Conclusão: Nossos resultados mostram a viabilidade desse tratamento em pacientes vasculares em nosso meio, mesmo em população de baixo nível socioeconômico, quando tratados em ambulatório especializado.Palavras-chave: Anticoagulantes, warfarina, efeitos adversos, doenças vasculares, trombose venosa, embolia pulmonar. AbstractObjective: To prospectively study the frequency of complications in patients treated with warfarin followed at Botucatu Medical School.Methods: Patients randomly selected among those with appointments scheduled from June 2002 to February 2004. At the first appointment, a protocol was filled with identification and clinical data. At every return or when the patient went to the hospital due to clinical events, another form was filled with the international normalized ratio, existence and type of clinical event and the conditions of use of vitamin K antagonists.Results: A total of 136 patients (61 men and 75 women), were followed; 99 patients with venous thromboembolism and 37 with arterial disease; 59 were from Botucatu and 77 were from other municipalities. Thirty clinical events were registered: nine of them were not related to the use of warfarin and 21 were hemorrhagic complications (38.8 per 100 patients-year). One hematemesis was considered severe (1.9 per 100 patients-year). The others were considered moderate or mild. There were no deaths, intracranial hemorrhage or cutaneous necrosis. The only significant association was frequency of hemorrhage and average international normalized ratio level.Conclusion: Our results demonstrate the feasibility of this treatment in vascular patients in our country, even in socially and economically poor populations, when treated in specialized clinics.

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“…For anticoagulation clinic testing, we assumed that patients spend 26% percent of their time (range, 8%-40%) below and 9% of their time (range, 1%-17%) above therapeutic range to reflect the averages of those reported by a number of large anticoagulation clinical trials, [13][14][15][16][17][18][19][20][21] as well as data from four observational studies. 3,6,22,23 For patient self-testing, patients were assumed to spend 6% of their time (range, 5%-15%) below and 5% of their time (range, 1%-7%) above therapeutic range, reflecting the average of those reported by White et al, 23 Anderson et al, 9 Ansell et al, 6 and Hasenkam et al 7 Associated with these estimates of time spent below, in, and above therapeutic range are first and subsequent thromboembolic and hemorrhagic event rates (Table 1). Transition probabilities for event rates were derived from a longitudinal study of patients seen in five anticoagulation clinics.…”

Section: The Decision Modelmentioning

confidence: 99%

The cost-effectiveness of different management strategies for patients on chronic warfarin therapy

et al. 2000

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OBJECTIVE:To examine the cost-effectiveness of moving from usual care to more organized management strategies for patients on chronic warfarin therapy. DESIGN:Using information available in the scientific literature, supplemented with data from a large health system and, when necessary, expert opinion, we constructed a 5-year Markov model to evaluate the health and economic outcomes associated with each of three different anticoagulation management approaches: usual care, anticoagulation clinic testing with a capillary monitor, and patient self-testing with a capillary monitor. PATIENTS:Three hypothetical cohorts of patients beginning long-term warfarin therapy were used to generate model results. MAIN RESULTS:Model results indicated that moving from usual care to anticoagulation clinic testing would result in a total of 1.7 thromboembolic events and 2.0 hemorrhagic events avoided per 100 patients over 5 years. Another 4.0 thromboembolic events and 0.8 hemorrhagic events would be avoided by moving to patient self-testing. When direct medical care costs and those incurred by patients and their caregivers in receiving care were considered, patient self-testing was the most costeffective alternative, resulting in an overall cost saving. CONCLUSIONS:

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Bleeding complications in oral anticoagulant therapy. An analysis of risk factors

Cited by 354 publications

References 21 publications

Age and the Risk of Warfarin‐Associated Hemorrhage: The Anticoagulation and Risk Factors In Atrial Fibrillation Study

Age and the Risk of Warfarin‐Associated Hemorrhage: The Anticoagulation and Risk Factors In Atrial Fibrillation Study

Complicações da terapia anticoagulante com warfarina em pacientes com doença vascular periférica: estudo coorte prospectivo

The cost-effectiveness of different management strategies for patients on chronic warfarin therapy

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