Plain English Summary
Background and study aims
Low intake of vitamin K in the diet has been linked to a higher risk of heart attacks and strokes. This may be because vitamin K is important in keeping blood vessels in good health; low levels of vitamin K are associated with stiffer blood vessels and deposits of calcium in the blood vessel wall. Vitamin K may also be important in keeping nerves working well which are important in maintaining balance and avoiding falls. It is not known whether taking extra vitamin K (as a tablet) can improve balance or blood vessel health, so the aim of this study is to test whether taking a vitamin K tablet for 6 months improves blood vessel health and improves balance in older people who have had (or are at risk of) a heart attack or stroke.
Who can participate?
Older people aged 70 and over who have had (or are at risk of) a heart attack or stroke
What does the study involve?
Participants are randomly allocated to take either vitamin K or a matching placebo (dummy) tablet once a day for 6 months. They are then followed up to assess their blood vessel health and balance.
What are the possible benefits and risks of participating?
If vitamin K improves blood vessel health, it might reduce the risk of heart attacks and strokes, but this study is too small to show this directly. Vitamin K is safe with no known side effects. It can interfere with the action of the drug warfarin, which is why patients on warfarin are excluded from the study.
Where is the study run from?
Ninewells Hospital (UK)
When is the study starting and how long is it expected to run for?
August 2011 to March 2013
Who is funding the study?
Chest Heart and Stroke Scotland (UK)
Who is the main contact?
Dr Miles Witham
m.witham@dundee.ac.uk
Trial website
Contact information
Type
Scientific
Primary contact
Dr Miles Witham
ORCID ID
http://orcid.org/0000-0002-1967-0990
Contact details
Ageing and Health
Ninewells Hospital
Dundee
DD1 9SY
United Kingdom
+44 (0)13 8263 2436
m.witham@dundee.ac.uk
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
R11/A137
Study information
Scientific title
Vitamin K to improve markers of vascular health and physical function in older people with vascular disease: a randomised controlled trial
Acronym
KIMVASC
Study hypothesis
To test whether vitamin K supplementation improves markers of vascular health in older people with vascular disease.
Ethics approval
East of Scotland NHS Research Ethics Committee, 12/09/2011, ref: 11/ES/0009
Study design
Parallel-group double-blind placebo-controlled randomised trial
Primary study design
Interventional
Secondary study design
Randomised parallel trial
Trial setting
Other
Trial type
Treatment
Patient information sheet
Not available in web format, please use the contact details to request a patient information sheet
Condition
Vascular disease
Intervention
Vitamin K2 (MK7 subtype) 100 mcg per day or placebo.
Added 18/08/2017:
Participants are randomised to take either:
1. Vitamin K2 (MK7 subtype) given as 100 mcg oral tablet once a day for 6 months
2. Matching placebo tablet, given once a day for 6 months
Treatment in both arms given for 6 months, which is also the length of follow up.
Intervention type
Supplement
Phase
Not Applicable
Drug names
Vitamin K
Primary outcome measure
Flow-mediated dilatation of the brachial artery measured at baseline and 6 months
Secondary outcome measures
Measured at baseline, 3 months and 6 months:
1. Markers of vascular function:
1.1. Arterial stiffness and reflectivity, measured using pulse wave velocity and augmentation index
1.2. Carotid intima-media thickness and compliance
2. Markers of vascular prognosis: brain natriuretic peptide (BNP), office blood pressure (BP) (lying and standing), total cholesterol, high density lipoprotein (HDL) cholesterol, low density lipoprotein (LDL) cholesterol
3. Markers of inflammation: high-sensitivity C-reactive protein
4. Serum MK7 levels, measured by high-performance liquid chromatography (HPLC)
5. Markers of physical function:
5.1. Short Physical Performance Battery; predicts disability, falls and death
5.2. Balance, measured using force plate analysis
5.3. Grip strength as a test of maximal muscle strength; predicts institutionalisation and death
Overall trial start date
01/08/2011
Overall trial end date
31/03/2013
Reason abandoned (if study stopped)
Eligibility
Participant inclusion criteria
1. Aged 70 and over
2. At least one of the conditions:
2.1. Hypertension (based on recorded diagnosis from primary or secondary care)
2.2. Diabetes mellitus (based on recorded diagnosis from primary or secondary care)
3. Established vascular disease: myocardial infarction [based on symptoms of ischaemia or electrocardiogram (ECG) changes, plus rise in cardiac enzymes]
4. Percutaneous transluminal coronary angioplasty
5. Coronary artery bypass grafting
6. Stroke/transient ischaemic attack (TIA) (diagnosis established in secondary care)
7. Peripheral vascular disease (symptoms of peripheral ischaemia and either a previous ankle/brachial pressure index < 0.7 or previous evidence of arterial stenosis on angiography or ultrasound)
Participant type
Patient
Age group
Senior
Gender
Both
Target number of participants
80
Participant exclusion criteria
1. Atrial fibrillation
2. Taking warfarin
3. Unable to give written informed consent
4. Unable to walk without human assistance (walking aids are permitted)
Recruitment start date
01/09/2011
Recruitment end date
30/09/2012
Locations
Countries of recruitment
United Kingdom
Trial participating centre
Ninewells Hospital
Dundee
DD1 9SY
United Kingdom
Sponsor information
Organisation
Tayside Academic Sciences Collaboration (UK)
Sponsor details
Level 3 Residences
Geroge Pirie Way
Ninewells Hospital
Dundee
DD1 9SY
United Kingdom
+44 (0)13 8274 0489
TASC@dundee.ac.uk
Sponsor type
University/education
Website
Funders
Funder type
Charity
Funder name
Chest Heart and Stroke Scotland (ref: R11/A137)
Alternative name(s)
CHSS
Funding Body Type
private sector organisation
Funding Body Subtype
professional associations and societies
Location
United Kingdom
Results and Publications
Publication and dissemination plan
Manuscript accepted for publication.
IPD sharing statement
The datasets generated during and/or analysed during the current study are available upon request from Dr Miles Witham (m.witham@dundee.ac.uk). Anonymised individual participant data on all those randomised will be made available to bona fide researchers for non-commercial use, subject to sight of an analysis plan and subject to appropriate data sharing agreements and approval from the trial Sponsor.
Intention to publish date
09/11/2017
Participant level data
Available on request
Basic results (scientific)
See additional file ISRCTN93213492_BasicResults_04Aug2017.pdf
Publication list
2016 results in: https://www.ncbi.nlm.nih.gov/pubmed/26892582
Publication citations
Additional files
- ISRCTN93213492_BasicResults_04Aug2017.pdf Uploaded 22/08/2017