Effect of paricalcitol vs calcitriol on hemoglobin levels in chronic kidney disease patients: a randomized trial

Recent studies suggest that vitamin D deficiency represents an additional cofactor of renal anemia, with several mechanisms accounting for this relationship. In line with it, the administration of vitamin D or its analogues has been associated with an improvement of anemia. There are no data, however, about a direct effect of paricalcitol on hemoglobin (Hb) levels. Therefore, we conducted a study to determine whether paricalcitol, compared to calcitriol, improves anemia in patients with chronic kidney disease (CKD). In this randomized trial 60 CKD patients stage 3b-5 and anemia (Hb levels: 10-12.5 g/dL) were assigned (1:1) to receive low doses of calcitriol (Group Calcitriol) or paricalcitol (Group Paricalcitol) for 6 months. All the patients had normal values of plasma calcium, phosphorus and PTH, a stable iron balance, and normal values of C-Reactive Protein. The primary endpoint was to evaluate the effects of the two treatments on Hb levels; the modifications in 24hr-proteinuria (UProt) were also evaluated. A significant Group x Time interaction effect was observed in the longitudinal analysis of Hb levels (F(1,172)=31.4, p