Influencia del metabolismo de la vitamina d en la respuesta a agentes eritropoyéticos en pacientes en hemodiálisis

Resumo

Anemic syndrome and the chronic kidney disease-mineral and bone disorders are common in hemodialysis patients. Iron supplements, erythropoiesis stimulating agents (ESA) and vitamin D (VD) analogs are needed for the control. The influence of vitamin D on the erythropoietic response has been reported, but the underlying mechanisms, remains unclear. Aims 1) To determine the influence of 25 VD and 1,25 VD and the use of paricalcitol on the erythropoietic response. 2) To determine the optimal paricalcitol dosage and the potential differences in comparison with the calcitriol on the ESA needs. Methodology Two different studies were conducted 1) A post-hoc analysis of the MIR-EPO study. 31 patients were included (23 un-der paricalcitol). The 25 VD and 1,25 VD levels were determined. The influences of their variation and the paricalcitol use of the erythropoietic response were eval-uated. Novel markers associated with anemia were assessed too. 2) Two crosses sectional studies: A single-center (58 patients screened) and other multicentric study (183 patients screened) were conducted to determine the opti- Vitamina D y respuesta eritropoyética mal paricalcitol dosages, and the potential differences in comparison with patients under calcitriol. Results 1) A non-significant increase in 25 VD levels was observed (24 ng/ml and 25 ng/ml, baseline and month 6, respectively). Such changes were associated with a de-crease in serum ferritin, and with an increase in 1,25 VD levels. The increase in 1,25 VD correlated with a reduction in Hb values. Those receiving paricalcitol needed lower ESA doses and was related to IL-6, and hepcidine changes. Soluble klotho levels were higher and plasma EPO levels increased in this group. 2) Observational studies. Up to 46 and 92 patients were respectively included; pari-calcitol dosages between 5 and 10g/week were associated with an improved erythropoietic response and lower ESA doses in comparison with those receiving calcitriol. Conclusions The 25 VD levels recommended do not seem to be related to benefits in the erythropoietic response in hemodialysis patients. Paricalcitol showed a positive influence on the ESA needs, by improving the iron utilization and for the elevation of EPO levels. Our data suggest differences in comparison with calcitriol.