Does parathyroid hormone affect erythropoietin therapy in dialysis patients?

ABSTRACT

The objective of this study was to assess the response to recombinant human erythropoietin [rHuEPO] during treatment of anemia in dialysis patients with hyperparathyroidism. A total of 118 patients with stage 5 renal failure on dialysis therapy were selected for this study. Anemia was treated with rHuEPO. Laboratory data for each patient included intact parathyroid hormone [iPTH], hemoglobin [Hb], hematocrit [Hct], blood urea nitrogen, serum creatinine, calcium, phosphate, and alkaline phosphatase. Patients with iPTH >32 pmol/l were considered hyperparathyroid. Erythropoietin resistance index [ERI] was expressed as the ratio of weekly rHuEPO dose/Hct level. Of the 118 patients, 83 [70.3%] were on hemodialysis [HD] and 35 [29.7%] were on continuous ambulatory peritoneal dialysis [CAPD]. Sixty-three patients [64.3%] with iPTH >32 pmol/l had Hb <11 g/dl, while 34 [54.8%] with iPTH <32 had Hb >11 g/dl [p = 04]. Thirty-three [56%] patients with iPTH >32 pmol/l had hemocrit <33%, while 38 [61.3%] with iPTH <32 had hemocrit <33% [p = 0.4]. The median value of weekly rHuEPO dose in HD patients [12,000 units] was significantly higher in comparison with CAPD patients [6,000 units; p < 0.0001]. ERI was significantly higher in HD than CAPD patients with iPTH <16 pmol/l [p = 0002] as well as with patients with 16-32 pmol/l [p = 0.012]. CAPD patients showed a reduced requirement for rHuEPO and better control of anemia compared with HD patients. ERI was also lower in CAPD than in HD patients. Hyperparathyroidism is a parameter predictive of rHuEPO hyporesponsiveness in dialysis patients