Monitoring 25-OH and 1,25-OH vitamin D levels in hemodialysis patients after starting therapy: Does it make sense?

Abstract

Background and aims: In hemodialysis patients, monitoring 25-hydroxyvitamin D (25(OH)D) levels is recommended. It is however unclear if monitoring 1,25-dihydroxyvitamin D (1,25(OH)₂D) levels is interesting.

Materials and methods: We repeatedly measured 1,25(OH)₂D (DiaSorin Liaison analyser) and 25(OH)D (LCMS/MS) concentrations in patients newly treated by active or native vitamin D to study the impact of such treatments on serum concentrations.

Results: Ten patients were included in the native and 12 in the active vitamin D group. In the native group, a significant increase was observed between the baseline and the last 25(OH)D concentrations available (21.65[17.39;25.26] versus 33.49[28.60;40.30] ng/mL, p = 0.0059). The baseline and last available 1,25(OH)₂D concentrations were not different (12.15[4.25;15.40] versus 11.35[9.72;21.85] pg/mL, p = 0.5566). In the active group, no difference was observed between the baseline and the last 25(OH)D concentrations (51.70[42.97;63.95] versus 50.89[42.02;64.49] ng/mL, p = 0.5186). The same observation was made for 1,25 (OH)₂D concentrations (25.65[17.05;41.85] versus 28.70[23.36;43.73] pg/mL, p = 0.6221). Using a linear mixed model, a significant change over time was only observed in 25(OH)D serum levels for patients treated by with native vitamin D.

Conclusion: Measuring 1,25(OH)2D levels in patients newly treated by active vitamin D does not seem useful in monitoring active vitamin D therapy.

Keywords: Alphacalcidol; Bone disease; Calcitriol; Cholecalciferol; Dialysis; Monitoring.