Comparison between calcitriol and calcitriol plus low-dose cinacalcet for the treatment of moderate to severe secondary hyperparathyroidism in chronic dialysis patients

Abstract

Aim: Uremic hyperparathyroidism (UHPT) has been shown to contribute to the development and progression of chronic kidney disease-mineral bone disorder. UHPT is frequently observed in chronic dialysis patients, and patients with UHPT are associated with increased risk of all-cause and cardiovascular mortality. Cinacalcet is a novel agent that increases sensitivity to the calcium-sensing receptor and is approved for control of UHPT. Nevertheless, cinacalcet is costly and information regarding efficacy of low-dose cinacalcet on UHPT is limited. Methods: We conducted a retrospective study to evaluate treatment with either low-dose calcitriol combined with low-dose cinacalcet (25 mg) (D-Cinacalcet) or calcitriol alone (VitD) in dialysis patients with moderate to severe UHPT. A total of 81 dialysis patients were enrolled (40 subjects in D-Cinacalcet group and 41 subjects in VitD group). Demographic data including age, gender, duration on dialysis and biochemical data were reviewed and recorded. Results: At the end of the study, the intact parathyroid hormone (iPTH) levels of the D-Cinacalcet group declined significantly (from 1166.0 ± 469.3 pg/mL to 679.8 ± 421.6 pg/mL, p < 0.0001), while there was no significant change in the VitD group. Significant decrease of serum calcium (Ca: 9.9 ± 0.6 mg/dL vs. 9.6 ± 0.8 mg/dL, p = 0.002), phosphorus (P: 5.9 ± 1.3 mg/dL vs. 4.9 ± 0.9 mg/dL, p < 0.0001) and calcium phosphate product (Ca × P: 58.7 ± 15.0 mg2/dL2 vs. 46.9 ± 8.9 mg2/dL2, p < 0.0001) were observed in the D-Cinacalcet group. In addition, the subjects in the D-Cinacalcet group had a greater proportion to achieve Kidney Disease Outcomes Quality Initiative (KDOQI)-recommended biochemical targets than the subjects in the VitD group (Ca: 48% vs. 24%; P: 78% vs. 32%; Ca × P: 85% vs. 37%; iPTH: 15% vs. 0%). Conclusions: We conclude that combination therapy of low-dose cinacalcet and calcitriol is more effective than calcitriol alone as a treatment for moderate and severe UHPT in chronic dialysis patients. Furthermore, this therapy is associated with improvement in hyperphosphatemia and hypercalcemia. © 2013 by the authors; licensee MDPI, Basel, Switzerland.