Effect of vitamin D supplementation versus placebo on hypertension in patients with vitamin D deficiency: a double blind randomized clinical trial

Objectives: To assess the effect of vitamin D supplementation versus placebo on hypertension in patients with vitamin D deficiency. Design: a double blind randomized clinical trial. Setting and conduct: The eligible patients with vitamin D deficiency who will refer to Farshchian Hospital during the study period will be enrolled into the trial. Inclusion criteria: Age of 18 to 75 years; systolic blood pressure equal to or greater than 140 mmHg or diastolic blood pressure equal to or greater than 90 mmHg in tow times; vitamin D deficiency. Exclusion criteria: Pregnancy; secondary hypertension; renal failure; a history of using vitamin D or calcium during the last three months; using Thiazide-type diuretics. Intervention group: Routine anti-hypertensive drugs plus gelatin tablet vitamin D (Calciferol) based on Vitamin D serum level (50,000 U once a week oral in subjects with Vitamin D serum level less than 20 ngr/mL and 1000 U in subjects with serum level between 20 to 30 ngr/mL) for 2 months Control group: Routine anti-hypertensive drugs plus gelatin tablet placebo once a week for 2 months. Primary outcome: Measuring systolic and diastolic blood pressure in sitting position from the right hand using mercury sphygmomanometer before intervention and then monthly for 2 months. Secondary outcome: Measuring serum Calciferol before intervention and then monthly for 2 months through laboratory test. Randomization: The patients will be randomly assigned to intervention and control groups using block randomization. Blinding: Patients will be unaware of the type of intervention. The physician who will examine the patients will not be aware of the intervention. The analyzer will be unaware of the type of interventions. Therefore, the trial will be run as double blind.

Vice-chancellor for Research the Technology, Hamadan University of Medical Sciences