Monthly cholecalciferol administration in haemodialysis patients: a simple and efficient strategy for vitamin D supplementation

Background. There is growing evidence of the usefulness of vitamin D supplementation in dialysis patients who are most often vitamin D deficient. Due to the long half-life of vitamin D, there is much interest in administering it intermittently for long-term adherence. However, there are no data to indicate which dosage would be most efficient. Objective. The aim was to assess the long-term efficiency and safety of a monthly oral dose of cholecalciferol (100 000 IU) in vitamin D-deficient haemodialysis (HD) patients. Methods. HD patients with a serum 25-hydroxyvitamin D (25(OH) D) level < 75 nmol/L were enrolled in a 15-month prospective study. The exclusion criteria were as follows: use of any vitamin D derivatives, prescription of cinacalcet and bisphosphonates, uncontrolled hypercalcaemia (> 2.55 mmol/L), hyperphosphataemia (> 2 mmol/L) and severe secondary hyperparathyroidism (SHPT; serum PTH > 600 pg/mL). Biological data were recorded in the following months: M-3, M0, M1, M3, M9 and M15. We aimed to maintain stable levels of the phosphate binder and oral and dialysate calcium during the course of the study. Results. Of the 250 patients screened, 161 were enrolled, and the results from 107 were recorded at the end of the study. Of these 107 patients, 56% were males, and the average age of the patient group was 66.4 +/- 15 years. Diabetics accounted for 36% of the total patients. The dialysis schedule ranged from 3 x 5 to 3 x 8 h, with a mean dialysate calcium concentration of 1.48 +/- 0.6 mmol/L. After 15 months, the mean serum 25(OH)D level increased from 32 +/- 13 to 105.8 +/- 27 nmol/L (P < 0.001) and plateaued after M3. Of the patients, 91% had a level higher than the target level (> 75 nmol/L), while none had levels > 200 nmol/L. The serum calcitriol (1,25(OH)(2)D) level increased from 13.7 +/- 14 to 45 +/- 13 pmol/L (P < 0.001) and plateaued after M9. The levels of serum PTH (median 295190 pg/mL, P < 0.001), bone alkaline phosphatase (20.5 +/- 9-17.1 +/- 7 mu g/L, P < 0.05) and beta-cross-laps (2.5 +/- 12.07 +/- 0.8 mu g/L, P < 0.05) decreased significantly. No significant changes were observed in the values of the following: calcaemia, phosphataemia, blood pressure, serum albumin, haemoglobin and C-reactive protein. Conclusions. Long-term monthly administration of oral cholecalciferol (100 000 IU) was a safe, effective, inexpensive and simple method for correcting vitamin D deficiency in almost 90% of the HD patients in this study and led to optimal compliance. The most evident consequences were a slight decrease in the levels of PTH and bone markers and an increase in the level of serum 1,25(OH)(2)D.