P1410IMPACT OF VITAMIN D SUPPLEMENTATION ON CKD-MBD HEMODIALYSIS PATIENTS - A PROSPECTIVE STUDY

Abstract

Abstract Background and Aims There are evidences suggesting that 50-90% of hemodialysis (HD) patients are vitamin D deficient [25(OH) D level <20 ng/mL] or insufficient (between 21 to 29 ng/mL). Recent guidelines recommend evaluation and supplementation low serum vitamin D levels in HD patients. However the effects of supplementation remains uncertain. Our aim was to evaluate the effect of supplementation on phosphocalcic metabolism and secondary hyperparathyroidism in HD patients of a hospital unit. Method Prospective study with an 18 months follow-up period. HD patients were supplemented with 12000 IU cholecalciferol 3 times a week if vitamin D level under 30ng/mL and 4000 IU if above. Every 6 months (3 time points) vitamin D, bone alkaline phosphatase (AF), calcium (Ca2+), phosphorus (P+) and intact parathyroid hormone (iPTH) blood levels were measured. Demographic, analytical and clinical data, including diabetic status, were analyzed. Categorical variables are presented as frequencies and percentages, continuous variables as means and standard deviations, or medians and interquartile ranges (IQR) for variables with skewed distributions. Statistical analysis was performed using SPSS version 21 for Windows. Results Sixty patients completed the follow-up period. The average was 74.70±1.43 years, 65% (n=39) were male and 41.7% (n=25) were diabetic. The average HD time at point 3 (18 months) was 3.15±3.62 years. A repeated measures ANOVA with a Greenhouse-Geisser correction showed that cholecalciferol supplementation significantly changed vitamin D blood levels along time (F(2.492;144.54)=26.832; p<0.001), with a statistically significant increase in vitamin D blood levels from time point 0 to point 3 (+8.27 ng/mL, p<0.001). There was also a significant reduction of phosphorus (-0.53mg/dL, p=0.017) and iPTH blood levels (-144.09 pg/nL p<0.001) in the same period. Seric calcium had a statistically significant increase from point 0 to 2 (+0.22 mg/dL, p=0.038). Using Pearson’s correlation, from point 0 to 3, we found a negative correlation between vitamin D and iPTH blood levels variation (Rs= -0.303, p=0.018) and a positive correlation between vitamin D and AF blood levels variation (Rs= 0.043, p=0.002). Conclusion Oral cholecalciferol supplementation increases significantly vitamin D blood levels and can be a good option in the management of secondary hyperparathyroidism and hypocalcemia. However, one of the limitations of our study was not to evaluate the use of medication such as P+ chelating agents and the small sample size. Therefore, large randomized clinical trials with clinically meaningful endpoints (fracture, hospitalization, parathyroidectomy, death) are still required to assess the usefulness of different vitamin D compounds for CKD and dialysis patients.