Low dose vitamin K to improve therapeutic quality control of oral anticoagulant treatment: a randomised double-blind placebo controlled trial

ISRCTN	ISRCTN14473912
DOI	https://doi.org/10.1186/ISRCTN14473912
Protocol serial number	Project 2005.2; NTR314
Sponsor	Leiden University Medical Center (LUMC) (The Netherlands)
Funder	Dutch Thrombosis Foundation (Trombosestichting Nederland) (The Netherlands)

Prospectively registered

Protocol

Statistical analysis plan

Results

Individual participant data

Record updated in last year

Plain English summary of protocol

Not provided at time of registration

Dr F.J.M. van der Meer
Scientific

Leiden University Medical Center
Department of Hematology
P.O. Box 9600
Leiden
2300 RC
Netherlands

Phone	+31 (0)71 5263901
Email	f.j.m.van_der_meer@lumc.nl

Primary study design	Interventional
Study design	Randomised, double-blinded, placebo controlled parallel group trial
Secondary study design	Randomised controlled trial
Scientific title
Study objectives	1. Oral anticoagulant control is less stable at a low average intake of vitamin K 2. As a consequence, a low dose vitamin K supplement results in a more stable anticoagulant effect in patients using vitamin K antagonists (VKA) 3. Dietary intake of vitamin K is associated with sensitivity to VKA and stability of anticoagulant treatment 4. Polymorphisms of the VKORC1 gene are associated with sensitivity to VKA and stability of anticoagulant treatment
Ethics approval(s)	Ethics approval received from the local medical ethics committee
Health condition(s) or problem(s) studied	Thrombosis, emboly, anticoagulant treatment
Intervention	1. Treatment group: 100 microgram vitamin K for 24 weeks 2. Placebo group: placebo for 24 weeks
Intervention type	Supplement
Primary outcome measure(s)	1. Quality of anticoagulant treatment 2. Expressed as time in therapeutic range
Key secondary outcome measure(s)	1. Number of international normalised ratios (INRs) in therapeutic range 2. Bleeding and thromboembolic complications
Completion date	01/06/2006

Participant type(s)	Patient
Age group	Adult
Lower age limit	18 Years
Upper age limit	80 Years
Sex	All
Target sample size at registration	200
Key inclusion criteria	1. Patients treated at the Leiden anticoagulation clinic with an indication for long-term oral anticoagulant therapy using the vitamin K antagonist phenprocoumon 2. Age between 18 and 80 years 3. Informed consent
Key exclusion criteria	1. Treatment by a medical specialist for liver failure 2. Haemo or peritoneal dialysis 3. Pregnancy or a planned pregnancy, puerperium 4. Any chronic condition with an expected median survival of less than 6 months an expected interruption of oral anticoagulant treatment of more than 1 week 5. Self-management of oral anticoagulant therapy 6. Other drugs affecting haemostasis (aspirin, heparin, clopidogrel)
Date of first enrolment	16/11/2004
Date of final enrolment	01/06/2006

Leiden University Medical Center

Leiden
2300 RC
Netherlands

Individual participant data (IPD) Intention to share	No
IPD sharing plan summary	Not provided at time of registration
IPD sharing plan