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Prolongation of the Interval Between Prothrombin Time Tests in Stable Patients II (PRINT-II)

18 de marzo de 2014 actualizado por: Sam Schulman, McMaster University

Prolongation of the Interval Between Prothrombin Time Tests in Stable Patients II (the PRINT II Study): a Randomized Controlled, Non-inferiority Trial Comparing 4-weekly With 12-weekly Testing and Dose-assessment

More than 2 million patients in North America are treated with warfarin - a "blood thinner" - to prevent blood clots in arteries or veins. The treatment has to be monitored with a blood test and the dose changed accordingly every 1-4 weeks. One third of the patients have very stable results and hardly ever have to change the dose. The investigators wish to show that the level of control of the treatment with warfarin in these very stable patients is not worse with 12-weekly testing. A pilot study the investigators performed indicated that 12-weekly testing would be safe but this has to be confirmed in a large study. One third of patients taking warfarin have not had any changes in the dose for the past 6 months or longer. These patients will be asked about participation in the study. They will be randomized to testing and dosing every 4 or 12 weeks. Each patient is in the study until it ends, which will be minimum 1 year and can be up to about 4 years. The study is designed to show that 12-weekly testing does not significantly increase the risk for major bleeding or blood clots. The results would be important for a large number of patients. An increase of the interval between blood tests from 4 to 12 weeks would reduce the burden for these patients on life-long treatment considerably.

Descripción general del estudio

Estado

Retirado

Condiciones

Intervención / Tratamiento

Descripción detallada

The study is a randomized, controlled, open-label, multi-center non-inferiority trial to demonstrate that the interval between internation normalized ration (INR) tests can be extended from the recommended 4 weeks to 12 weeks for patients with stable INRs. PROBE design. Patients receiving warfarin therapy that have exhibited INR stability, defined as no change in maintenance dose for at least 6 months, are potentially eligible for enrolment in the study. The primary outcome is a composite of major bleeding (ISTH criteria) plus objectively verified arterial or venous thromboembolism (excluding superficial thrombophlebitis) plus death related to thromboembolism. Justification: the study is not reflecting a "trade-off" scenario where one regimen is expected to be more effective at the cost of increased harm compared to the other regimen. Conversely, the potential disadvantage of the experimental regimen in this trial is increased variability in INR, which may result in an increased rate of low as well as high INRs and therefore potentially an increase of both types of clinical events.

Tipo de estudio

Intervencionista

Fase

  • Fase 3

Contactos y Ubicaciones

Esta sección proporciona los datos de contacto de quienes realizan el estudio e información sobre dónde se lleva a cabo este estudio.

Ubicaciones de estudio

  • Canadá
    • Ontario
      • Hamilton, Ontario, Canadá, L8L 2X2
        • Hamilton Health Sciences - General Hospital

Criterios de participación

Los investigadores buscan personas que se ajusten a una determinada descripción, denominada criterio de elegibilidad. Algunos ejemplos de estos criterios son el estado de salud general de una persona o tratamientos previos.

Criterio de elegibilidad

Edades elegibles para estudiar

18 años y mayores (Adulto, Adulto Mayor)

Acepta Voluntarios Saludables

No

Géneros elegibles para el estudio

Todos

Descripción

Inclusion Criteria:

  • long-term warfarin for prophylaxis of arterial embolism due to atrial fibrillation or mechanical heart valve replacement OR secondary prophylaxis after VTE
  • therapeutic INR range of 2.0-3.0 or 2.5-3.5
  • anticoagulation therapy has been managed by the study site for at least 6 months prior to enrollment
  • warfarin maintenance dose has remained unchanged for the previous 6 months or longer

Exclusion Criteria:

  • Age < 18 years
  • Life expectancy of less than 1 year
  • Congestive heart failure or other diagnosis where the condition or its treatment is expected to affect the stability of INR (e.g. cancer requiring chemotherapy)
  • Attending physician believes that patient is not suitable for the study (for instance, psychiatric disorder; history of non-compliance; newly diagnosed disease which by itself, via the treatment required or the effects thereof may cause instability of INRs)
  • Patients who perform self-testing
  • Geographic inaccessibility
  • Failure to obtain written consent

Plan de estudios

Esta sección proporciona detalles del plan de estudio, incluido cómo está diseñado el estudio y qué mide el estudio.

¿Cómo está diseñado el estudio?

Detalles de diseño

  • Propósito principal: Tratamiento
  • Asignación: Aleatorizado
  • Modelo Intervencionista: Asignación paralela
  • Enmascaramiento: Ninguno (etiqueta abierta)

Armas e Intervenciones

Grupo de participantes/brazo
Intervención / Tratamiento
Sin intervención: Standard interval between PT testing
Prothrombin time (PT) is tested every 4 weeks, according to American College of Chest Physicians (ACCP) Guidelines up to 2008 for stable patients on warfarin.
Experimental: Prolonged interval between PT testing
Prothrombin time (PT) is tested every 12 weeks, according to suggestion in American College of Chest Physicians (ACCP) Guidelines of 2012 for stable patients on warfarin.
Otro: Prolonged interval between PT testing
Patients in the intervention group will be scheduled for prothrombin time testing and dosing of warfarin every 12 weeks instead of every 4 weeks. This has been suggested in the latest edition of the ACCP guidelines as a possibility for very stable patients. In order to change this from a suggestion to a formal recommendation a study powered for clinically important outcomes is needed.
Otros nombres:
  • INR (International Normalized Ratio) tests

¿Qué mide el estudio?

Medidas de resultado primarias

Medida de resultado
Medida Descripción
Periodo de tiempo
Composite of major bleeding and objectively verified arterial or venous thromboembolism
Periodo de tiempo: Average 3 years
The justification for a composite outcome including both bleeding and thromboembolism is that the study is not reflecting a "trade-off" scenario where one regimen is expected to be more effective at the cost of increased harm compared to the other regimen. Conversely, the potential disadvantage of the experimental regimen in this trial is increased variability in prothrombin time, which may result in an increased rate of short as well as long prothrombin times and therefore potentially an increase of both types of clinical events.
Average 3 years

Medidas de resultado secundarias

Medida de resultado
Medida Descripción
Periodo de tiempo
All-cause mortality
Periodo de tiempo: Average 3 years
Average 3 years
Any bleeding
Periodo de tiempo: Average 3 years
This is the composite of major and minor bleeding
Average 3 years

Colaboradores e Investigadores

Aquí es donde encontrará personas y organizaciones involucradas en este estudio.

Patrocinador

McMaster University

Publicaciones y enlaces útiles

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Publicaciones Generales

Fechas de registro del estudio

Estas fechas rastrean el progreso del registro del estudio y los envíos de resultados resumidos a ClinicalTrials.gov. Los registros del estudio y los resultados informados son revisados ​​por la Biblioteca Nacional de Medicina (NLM) para asegurarse de que cumplan con los estándares de control de calidad específicos antes de publicarlos en el sitio web público.

Fechas importantes del estudio

Inicio del estudio

1 de abril de 2014

Finalización primaria (Anticipado)

1 de abril de 2018

Finalización del estudio (Anticipado)

1 de octubre de 2018

Fechas de registro del estudio

Enviado por primera vez

21 de julio de 2012

Primero enviado que cumplió con los criterios de control de calidad

26 de julio de 2012

Publicado por primera vez (Estimar)

31 de julio de 2012

Actualizaciones de registros de estudio

Última actualización publicada (Estimar)

20 de marzo de 2014

Última actualización enviada que cumplió con los criterios de control de calidad

18 de marzo de 2014

Última verificación

1 de marzo de 2014

Más información

Términos relacionados con este estudio

Palabras clave

Términos MeSH relevantes adicionales

Otros números de identificación del estudio

  • PRINT-II-2012

Esta información se obtuvo directamente del sitio web clinicaltrials.gov sin cambios. Si tiene alguna solicitud para cambiar, eliminar o actualizar los detalles de su estudio, comuníquese con register@clinicaltrials.gov. Tan pronto como se implemente un cambio en clinicaltrials.gov, también se actualizará automáticamente en nuestro sitio web. .

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