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ISRCTN
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ISRCTN63688695
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ClinicalTrials.gov identifier
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Public title
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Does vitamin D reduce blood pressure and left ventricular (LV) mass in resistant hypertensive patients with vitamin D insufficiency?
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Scientific title
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Acronym
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N/A
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Serial number at source
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Res08/A115
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Study hypothesis
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Vitamin D insufficiency is common and low vitamin D levels are associated with higher blood pressure. Pilot data and previous studies suggest that vitamin D has anti-hypertensive effects, which may be mediated by pathways different from other anti-hypertensives. Vitamin D has not previously been studied as an anti-hypertensive in patients with resistant hypertension - a group for whom new approaches are urgently needed as they remain at high risk of cardiovascular events despite modern anti-hypertensive therapy.
Hypothesis:
That vitamin D supplementation in patients with resistant hypertension and insufficient vitamin D levels will lead to clinically important reductions in blood pressure.
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Ethics approval
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Ethics approval pending as of 28/03/2008.
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Study design
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Double blind, placebo controlled, parallel group randomised trial
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Countries of recruitment
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United Kingdom
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Disease/condition/study domain
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Hypertension
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Participants - inclusion criteria
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1. Aged greater than 18 years, either sex
2. Serum 25-hydroxy vitamin D less than 75 nmol/L
3. Office blood pressure (BP) greater than 140/90 mmHg despite three or more anti-hypertensives
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Participants - exclusion criteria
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1. Hypertension known to be due to a correctable underlying medical or surgical cause
2. Estimated glomerular filtration rate less than 40 ml/min (by four variable Modification of Diet in Renal Disease [MDRD] equations)
3. Liver function tests (alanine aminotransferase [ALT], bilirubin, alkaline phosphatase) greater than 3 x normal
4. Corrected calcium greater than 2.60 mmol/L or less than 2.15 mmol/L
5. Known metastatic malignancy or sarcoidosis
6. Clinical diagnosis of osteomalacia
7. History of renal calculi
8. Diagnosis of heart failure with left ventricular systolic dysfunction
9. Atrial fibrillation
10. Already taking vitamin D supplements. Consumption of fish oils will not be a contra-indication to enrolment.
11. Unable to give written informed consent
12. Pregnant or of childbearing age and not taking reliable contraception
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Anticipated start date
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01/08/2008
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Anticipated end date
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31/07/2010
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Status of trial
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Ongoing
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Patient information material
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Not available in web format, please use the contact details below to request a patient information sheet
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Target number of participants
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74
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Interventions
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100,000 units of oral vitamin D3 every two months or placebo.
Total treatment duration: 4 months
Total follow up: 6 months
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Primary outcome measure(s)
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Change in office BP, measured at 0, 2, 4 and 6 months.
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Secondary outcome measure(s)
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Change in LV mass index (measured by cardiac magnetic resonance imaging [MRI]), measured at 0 and 6 months.
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Sources of funding
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Chest Heart and Stroke Scotland (UK) (ref: Res08/A115)
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Trial website
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Publications
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Contact name
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Prof
Allan
Struthers
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Address
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Dept of Clinical Pharmacology
Ninewells Hospital
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City/town
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Dundee
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Zip/Postcode
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DD1 9SY
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Country
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United Kingdom
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Email
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a.d.struthers@dundee.ac.uk
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Sponsor
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University of Dundee (UK)
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Address
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Research and Innovation Services
11 Perth Road
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City/town
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Dundee
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Zip/Postcode
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DD1 4HN
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Country
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United Kingdom
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Email
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j.z.houston@dundee.ac.uk
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Sponsor website:
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http://www.dundee.ac.uk/
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Date applied
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28/03/2008
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Last edited
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21/04/2008
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Date ISRCTN assigned
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21/04/2008
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