Background: Vitamin D (VD) deficiency in chronic lymphocytic leukemia (CLL) is associated with inferior prognosis, shorter time to treatment and worse overall survival. VD deficiency is the first potentially modifiable prognostic factor in CLL. Currently, however, there is a lack of studies concerning VD supplementation in CLL patients.
Aim: To evaluate the efficacy and safety of VD supplementation in patients with CLL.
Methods: A 6-month interventional study was conducted in CLL patients with lower serum 25-OH-D3 concentrations (< 30 ng/ml) than currently recommended. Patients with VD insufficiency (20-30 ng/ml) received 2000 IU of cholecalciferol/day, patients with moderate deficiency (10-19.9 ng/ml) received 4000 IU/day, and patients with severe VD deficiency (<10 ng/ml) received 6000 IU/day.
Results: In the analyzed group of 13 CLL subjects, only 1 patient had a VD level within the optimal range (30-80 ng/ml), 7 had an insufficient concentration, 4 had moderate deficiency, and 1 had severe deficiency. Secondary hyperparathyroidism was diagnosed in 4 subjects. Cholecalciferol supplementation (mean dose of 3384 ± 1211 IU) was followed by a significant increase in 25-OH-D3 concentration (from 17.3 ± 5.8 to 41.4 ± 17.5 ng/ml; p<0.05) and decrease in PTH (p<0.05). Five patients did not achieve the recommended 25-OH-D3 concentration. Calcium level remained unchanged and no patients developed hypercalcemia.
Conclusions: VD replenishment is safe and can be effectively achieved by means of the employed cholecalciferol dosage in the majority of patients. However, some subjects may require higher doses to obtain the optimal level and immune function.