The Effect of Vitamin D3 Supplementation on Physical Performance in Ambulatory Patients on Hemodialysis

Abstract

Objective: The purpose of this study was to investigate the effect of cholecalciferol (vitamin D3) supplementation on physical performance in ambulatory hemodialysis (HD) patients. Design and Setting: This randomized, double-blind, placebo-controlled study was conducted in three dialysis centers in eastern Alabama. Subjects and Intervention: HD patients with serum 25-hydroxyvitamin D [25(OH)D] concentrations of less than 30 ng/mL and capable of ambulating independently were recruited for the study. Patients were randomly assigned to receive either vitamin D3 or placebo. Patients receiving cholecalciferol were provided with one 50,000 IU pill per week for 8 weeks followed by one 50,000 IU pill every 2 weeks for the next four weeks. Patients receiving the placebo followed the same dosing schedule. Main outcome measures: Physical performance changes pre and post intervention included: timed jump up and go test (JUG); timed 20-foot walk; timed repeated chair stand (RCS); Physical Functioning results from the Medical Outcomes Study 36 Item Short Form Health Status Questionnaire (SF36); 25(OH)D concentrations and other biochemical values. Results: After the intervention, the supplemented group (n=25) had significantly higher serum 25(OH)D concentrations than the placebo group (n=21) (51.8±12.9 vs. 16.0±5.2 ng/mL, respectively) and significantly lower plasma PTH concentrations than the placebo (251.7±264.8 vs. 491.5±587.0 pg/mL, respectively). The supplemented group exhibited significantly decreased times to complete the RCS from pre- to post-intervention, but the significance was lost in the between group comparison (-2.7 seconds vs. -0.6 seconds). Scores on the SF36 questionnaire were significantly correlated with baseline serum 25(OH)D concentrations. Conclusion: Supplementation with vitamin D can correct deficient serum 25(OH)D concentrations in HD patients. Serum 25(OH)D concentrations have a positive impact on patient well-being as measured by the SF36 questionnaire. Further research needs to be done to evaluate physical performance improvements in studies of longer duration. Key words: Hemodialysis, Vitamin D, cholecalciferol, skeletal muscle, CKD