Vitamin D Supplementation in Children With Sickle Cell Disease

Sickle cell disease (SCD) is a genetic disease characterized by abnormal hemoglobin, the main constituent of red blood cells. People with SCD have nutritional deficiencies, and vitamin D deficiency is one of the most common. Symptoms of vitamin D deficiency are similar to those of SCD and include chronic pain and bone complications. Correcting vitamin D nutrition of children with SCD represents a treatment that will improve their health. A single oral high-dose of vitamin D3 will be given to SCD children during one of their follow-up visits at the SCD clinic of CHU Sainte-Justine, Montreal, Canada. This mode of administration was chosen to ensure a better adherence to the treatment. The investigators will determine whether this dose is safe and its administration feasible in clinic. The impact of this dose on blood vitamin D and calcium, urinary calcium, growth, inflammation, bone health, pain and quality of life will also be assessed. This study intends to propose a new intervention to improve the nutrition of children with this disease.

Vitamin D deficiency is one of the most common nutritional conditions among patients with sickle cell disease (SCD). Since vitamin D deficiency and SCD share common manifestations including chronic pain, poor bone health and chronic systemic inflammation, it is reasonable to postulate that vitamin D deficiency may contribute to these complications. Thus, optimizing vitamin D nutrition represents an inexpensive strategy that may improve vitamin D status and health outcomes in SCD children. The working hypothesis is that administration of a single oral bolus of 300,000 IU of vitamin D3 to SCD children will result in the attainment of vitamin D sufficiency (25OHD levels >75 nmol/L) in 80% of participants after 3 months. The primary objectives are to assess feasibility, acceptability, and safety of the vitamin D3 bolus while secondary objectives are related to the mean change in serum 25OHD from baseline to 3 months post-bolus and its clinical impact. Seventy-two SCD children (5-17 years, SS and SC genotypes) will be randomized to one bolus of 300,000 IU of vitamin D3 or identical placebo. Blood will be collected at baseline and 3-month post-bolus to measure serum 25OHD and calculate the change from baseline at 3 months (efficacy outcomes). Other outcomes include urinary calcium/creatinine ratio and serum calcium (safety), questionnaires (acceptability and musculoskeletal pain) and parameters related to growth, haematology, inflammation and bone health (exploratory outcomes).

This is a randomised, quadruble-blind, placebo-controlled, parallel-group trial of vitamin D3 bolus supplementation.

The Applied Clinical Research Unit of Sainte-Justine UHC will generate the randomisation scheme. Group allocation codes will be held in a secure location with a restricted access by the Central pharmacy (Sainte-Justine UHC). All participants and research personnel, including the nurse, research trainee and research team will be blinded to group assignment. The supplier Euro-Pharm will provide the placebo and vitamin D3 preparations in coded bottles. Pharmacy will prepare the 6-mL bolus in coded syringes following the randomisation scheme.

Placebo identical to the vitamin D bolus in taste and appearance. The placebo will be administered once, at the beginning of the study. The oral liquid placebo will be prepared at the Pharmacy in coded syringes and will be administered to the participants by a nurse at the sickle cell disease Clinic.

The vitamin D bolus is an oral liquid supplement that will be administered once, at the beginning of the study. The oral liquid vitamin D bolus will be prepared at the Pharmacy in coded syringes and will be administered to the participants by a nurse at the sickle cell disease Clinic.The dose of vitamin D3 contained in the bolus is 300 000 IU.

Group difference in mean change of serum amino-terminal propeptide of type I collagen (P1NP) from baseline to 3 months

Musculoskeletal pain will be assessed with the Brief Pain Inventory (BPI). Group difference in the mean change in BPI scores.

Health-related quality of life will be assessed through the Pediatric Quality of life (PedQoL) inventory. Group difference in the mean change in PedQoL scores.

Occurrence of sickle cell disease complications affecting bone, the kidneys, the retina, blood vessels, the heart, the lungs, the spleen, the liver and gallbladder during the study period

Inclusion Criteria: Children aged between 5 and 17 years old who are followed up at the SCD Clinic, CHU Sainte-Justine, Montreal, Canada. Exclusion Criteria: Conditions or use of medications known to interfere with calcium or vitamin D absorption or metabolism Known hypercalcemia Conditions characterized by a hypersensitivity to vitamin D (e.g. granulomatous disorders) Patients clinically diagnosed with rickets or other conditions requiring vitamin D therapy History or presence of urolithiasis Anticipated difficult follow up Patients already enrolled in other investigational studies Patients who have recently been hospitalized for severe pain crisis or acute sickle complication in the past 2 weeks Patients with unresolved pain issues

Soe HHK, Abas AB, Than NN, Ni H, Singh J, Said ARBM, Osunkwo I. Vitamin D supplementation for sickle cell disease. Cochrane Database Syst Rev. 2020 May 28;5(5):CD010858. doi: 10.1002/14651858.CD010858.pub3.