A pilot study to assess feasibility of methods of an observer-blinded randomised controlled trial of the effect of vitamin D supplementation in Chronic Kidney Disease and low vitamin D levels on markers of vascular function (Flow Mediated Dilatation of Brachial Artery), vascular structure (Carotid Intima Media Thickness) and Immune Regulation (frequencies of CD4+CD28null T lymphocytes ad Regulatory T lymphocytes).
The study is a single (observer) blinded feasibility pilot randomised study. Study subjects will be recruited from clinics run by St George's Hospital Renal Department and randomised to treatment arm or no treatment arm. In treatment arm, six doses of vitamin D tablets (cholecalciferol 100,000 IU, five capsules total) will be administered on weeks 0, 4, 8, 12, 16 and 20. In the no-treatment arm the participants receive no cholecalciferol. Participants will have serum calcium levels measured at week 12. All participants will undergo estimation of endothelial function, carotid intima-media thickness, CD4+CD28null and regulatory T cell frequency in week 0 and week 26. The observer will be blinded to whether the patient is in the treatment or no-treatment arm whilst the following tests are performed: 1. Measurement of Brachial Artery Flow Mediated Dilatation 2. Measurement of Carotid Intima Media Thickness 3. Quantification of CD4+CD28null and regulatory T cell frequency The pilot study will assess feasibility of the study methods.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
36
(aviticol) 5x 20,000unit capsules administered monthly over 20 weeks
Debasish Banerjee
London, Tooting, United Kingdom
Recruitment rate
Percentage of patients recruited from those eligible for the study.
Time frame: 3 months
Retention rate
Percentage of patients recruited who completed the follow up investigations
Time frame: 6 months
Acceptability to patients of randomisation procedures
Acceptability as assessed by quantitative and qualitative analysis of Participant Experience Survey
Time frame: 6 months
Randomisation procedure
Comparison of baseline indices of two patient groups
Time frame: 6 months
Maintenance of single (observer) blinding
Incidences of unblinding of study investigator
Time frame: 6 months
Adherence to vitamin D supplementation
Subjective adherence as assessed by Participant Experience Survey and biochemical correlation by comparison of follow up vitamin D levels
Time frame: 6 months
Witnessed change in FMD between treated and untreated subjects
Flow Mediated Dilatation
Time frame: 6 months
Witnessed change in CIMT between treated and untreated subjects
Carotid Intima Media Thickness
Time frame: 6 months
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Witnessed change in T lymphocyte subset frequency between treated and untreated subjects
CD4+CD28null T lymphocytes and Regulatory T cells as determined by flow cytometry of whole blood
Time frame: 6 months