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Trial record 3 of 157 for:    warfarin AND Vitamin K

Low Dose Supplementation to Improve Anticoagulation Control With Oral Vitamin K as an Adjuvant to Warfarin Therapy (LOCK)

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ClinicalTrials.gov Identifier: NCT00794755
Recruitment Status : Completed
First Posted : November 20, 2008
Last Update Posted : July 27, 2011
Sponsor:
Information provided by:
Ottawa Hospital Research Institute

Tracking Information
First Submitted Date  ICMJE November 18, 2008
First Posted Date  ICMJE November 20, 2008
Last Update Posted Date July 27, 2011
Study Start Date  ICMJE November 2008
Actual Primary Completion Date April 2010   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: November 19, 2008)
  • Anticoagulation control -- Point estimates (and standard deviations) for the following variables: Percent time in therapeutic range, standard deviation of INRs, number of INRs outside of therapeutic range, and number of dose changes [ Time Frame: At study initiation (for the six month pre-intervention period) and at study completion (after the six-month intervention period) ]
  • Recruitment Numbers -- Number of patients deemed eligible, Number of patients solicited, Number of patients screened, Number of patients enrolled, and Number of enrolled patients lost to follow-up [ Time Frame: Monthly ]
Original Primary Outcome Measures  ICMJE Same as current
Change History Complete list of historical versions of study NCT00794755 on ClinicalTrials.gov Archive Site
Current Secondary Outcome Measures  ICMJE
 (submitted: November 19, 2008)
  • Bleeding Events -- Both major and minor as defined by the International Society on Thrombosis and Haemostasis (ISTH) criteria [ Time Frame: Over 6 month study period ]
  • Recurrent thrombosis [ Time Frame: Over six month study period ]
Original Secondary Outcome Measures  ICMJE Same as current
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE Low Dose Supplementation to Improve Anticoagulation Control With Oral Vitamin K as an Adjuvant to Warfarin Therapy
Official Title  ICMJE A Phase III Pilot RCT (Randomized, Controlled Trial) to Assess the Effectiveness of Low Dose Vitamin K1 (200 Micrograms Per Day) on Improving Anticoagulation Control in Unstable Patients on Warfarin
Brief Summary The main objective of this study is to assess the effectiveness of low dose Vitamin K1 (200 micrograms per day) at improving anticoagulation control in unstable patients on warfarin. This study will also aim to look at effectiveness in the context of genes known to influence warfarin metabolism, variability in the consumption of Vitamin K rich foods, and patient knowledge about warfarin anticoagulation -- factors which have been associated with anticoagulation control and which can influence the effectiveness of this intervention in clinical practice.
Detailed Description A double-blinded placebo controlled pilot RCT assessing the effectiveness of daily supplementation with low dose Vitamin K1 (200 micrograms per day) against placebo at improving anticoagulation control. Previous studies assessing the efficacy of this intervention have been small and further trials are required to evaluate the true effectiveness and safety profile. Furthermore the impact of genetic polymorphisms, known to impact warfarin metabolism, on the effectiveness/safety of this intervention will also be assessed in this study. Demographic and clinical variables as well as potential confounding variables such as variable dietary Vitamin K intake, concomitant interacting medications, and anticoagulation knowledge will be assessed in this study. Given that this is a pilot study we will be looking at recruitment numbers and necessary parameter estimates to determine the number of patients available at our institution for the study. Power analysis will be performed to evaluate the treatment effect size between the placebo and intervention groups.
Study Type  ICMJE Interventional
Study Phase  ICMJE Phase 3
Study Design  ICMJE Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Condition  ICMJE Coagulation
Intervention  ICMJE
  • Dietary Supplement: Vitamin K1 (Phytonadione)
    Vitamin K1 tablets (100 micrograms per tablet) will be taken by patients randomized to the Vitamin K arm. Dosage is two tablets per day (200 micrograms per day) to be taken with warfarin for the 6 month study period.
  • Dietary Supplement: Placebo
    Lactose-based placebo tablets (identical in appearance to the Vitamin K1 tablets) will be taken by patients randomized to the placebo arm. Dosage is two tablets per day to be taken with warfarin for the 6 month study period.
Study Arms  ICMJE
  • Active Comparator: Vitamin K
    Intervention: Dietary Supplement: Vitamin K1 (Phytonadione)
  • Placebo Comparator: Placebo
    Intervention: Dietary Supplement: Placebo
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Completed
Estimated Enrollment  ICMJE
 (submitted: November 19, 2008)
100
Original Estimated Enrollment  ICMJE Same as current
Actual Study Completion Date  ICMJE April 2010
Actual Primary Completion Date April 2010   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • >= 18 years old
  • Have been on warfarin anticoagulation for at least 9 months
  • Have an INR target range of 2.0-3.0
  • Have "unstable" anticoagulation control, defined as in the preceding 6 months having at least 3 INRs out of range (>= 3.2 or =<1.8) or at least 3 warfarin dose changes
  • Have anticoagulation managed by the Ottawa Hospital Thrombosis Clinic
  • Able to provide written, informed consent

Exclusion Criteria:

  • Anticipated interruption or termination of warfarin anticoagulation in the next six months for a period of 1 week or greater
  • Patient instability in the preceding six months suspected to be due to a) Interruption of warfarin therapy for a period of 1 week or more or b) Significant non-compliance (assessed from patient record)
  • Possess a known allergy to Vitamin K or lactose based placebos
  • Unable/Refusal to provide written, informed consent
Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE 18 Years and older   (Adult, Older Adult)
Accepts Healthy Volunteers  ICMJE No
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE Canada
Removed Location Countries  
 
Administrative Information
NCT Number  ICMJE NCT00794755
Other Study ID Numbers  ICMJE OHREB #2008555-01H
Has Data Monitoring Committee Yes
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Responsible Party Dr. Philip S Wells (Chair, Department of Medicine), Ottawa Hospital Research Institute (OHRI)
Study Sponsor  ICMJE Ottawa Hospital Research Institute
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Philip S Wells, MD, MSc Ottawa Hospital, Ottawa Health Research Institute
PRS Account Ottawa Hospital Research Institute
Verification Date July 2011

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP