Effects of Cholecalciferol on Osteoprotegerin Levels in Patients on Peritoneal Dialysis

Effects of Cholecalciferol on Osteoprotegerin Levels and Other Clinical Outcomes in Chronic Kidney Disease Patients on Peritoneal Dialysis: a Randomized Controlled Trial

Aim: To investigate whether cholecalciferol (4800 U/daily) or placebo for 16 weeks reduces proteins levels associated with vascular calcification (osteoprotegerin, osteopontin, osteocalcin) in patients treated with peritoneal dialysis and 25(OH) vitamin D deficiency.

Patients with chronic kidney disease on peritoneal dialysis have very low 25-(OH) vitamin D levels. Vitamin D deficiency may be involved in generalized atherosclerosis, vascular calcification and cardiovascular mortality. Among others, Osteoprotegerin (OPG) has been implicated in the pathogenesis leading up vessel calcification in this patients. Furthermore, very low levels of 25-(OH) vitamin D in peritoneal dialysis patients are associated with increased levels of OPG and high values of vascular calcification scores in x-rays.

It is unknown whether cholecalciferol supplementation in patients on peritoneal dialysis with low levels of 25-(OH) vitamin D could change the proteins associated with vascular calcification.

The objective is to conduct a randomized, double-blind, placebo-controlled study focusing on the impact of Cholecalciferol substitution in 25-OH vitamin D deficient peritoneal dialysis patients on circulating OPG and other osteogenic biomarkers levels during 16 weeks of intervention.

Moreover, the impact of cholecalciferol on serum calcium and phosphorus levels, Kidney Disease Quality of Life Short Form, and ultrasound characteristics of carotid arterial will be performed during the first four weeks after inclusion, and after 28 weeks postintervention.

Peritoneal dialysis patients found to have 25-(OH) vitamin D levels <20 ng/ml will be included and will be randomized to receive either oral cholecalciferol therapy or placebo. Cholecalciferol will be administered at a daily dose of 4800 IU over a time period of 16 weeks.

All in all, 58 subjects will be included in this study.

Inclusion Criteria:

• Peritoneal dialysis treatment for at least 3 months.
• Concentrations of 25-oh vitamin D <20 ng / mL
• Corrected calcium <10.5 mg / dL
• Serum phosphorus <7.0 mg / dL
• Intact parathyroid hormone > 50 pg / mL and <1500 pg/mL

Exclusion Criteria:

• Active participation in another protocol.
• Vitamin D deficiency due to a hereditary disease or liver disease.
• Use of cholecalciferol ≥ 2000 IU per day within 6 months prior
• New prescription of calcitriol or paricalcitol at any dose within three months prior to the intervention (The subjects may be taking calcitriol or paricalcitol only if these drugs are taken at least three months before and no substantial changes in dosage have been made).
• Use of bisphosphonates.
• Treatment with anticonvulsants or other drugs that affect the metabolism of vitamin D.
• Pregnancy and lactation.
• Active cancer or other active inflammatory disease.
• HIV or AIDS