Abstract: Objective To study the effect of cinacalcet combined with small dose of calcitriol for the treatment of refractory secondary hyperparathyroidism (SHPT) in continuous ambulatory peritoneal dialysis (CAPD) patients. Methods We recruited 16 CAPD patients with SHPT refractory to short period of large dose of calcitriol during the period from May 2015 to Jan. 2016. We then observed the effect of cinacalcet combined with small dose of calcitriol in these patients. Serum and urine samples were collected, parathyroid ultrasonography was examined, and serum Ca, P, ALP, iPTH and albumin were assayed before and after the
therapy. Results After the therapy of cinacalcet combined with small dose of calcitriol, serum iPTH, Ca, P, and CaxP product decreased significantly, as compared with those before the treatment (iPTH: 257.84±99.82 pg/ml, F=13.152, P<0.01; Ca: 2.22±0.11 mmol/L, F=4.602, P<0.05; P: 1.28±0.37 mmol/L, F= 8.723, P<0.01; CaxP product: 34.69±9.54 mmol2/L2, F=8.683, P<0.01); hemoglobin and albumin changed insignificantly (Hb: 112.81±10.80 g/L, F=0.744, P＞0.05; albumin: 37.34±4.98 g/L, F=0.624, P＞0.05). After the therapy, the size of parathyroid decreased in 8 of the 12 patients with parathyroid hyperplasia; in 13 symptomatic patients, clinical symptoms alleviated in 11 patients and relieved in one patient, and parathyroidectomy was conducted in one patient. Conclusion Cinacalcet combined with small dose of calcitriol is effective, noninvasive and low risk for the treatment of CAPD patients with refractory SHPT. Parathyroidectomy may not be necessary in some patients using this therapy. We recommend this therapy as the primary management for CAPD patients with refractory SHPT.

Key words: Cinacalcet, Small dose of calcitriol, Continuous ambulatory peritoneal dialysis, Refractory secondary hyperparathyroidism, Clinical observation