Implementation of 'K/DOQI Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease' after the introduction of cinacalcet in a population of patients on chronic haemodialysis

Abstract

The purpose of the present study was to evaluate the impact of cinacalcet administration on the attainment of Kidney Disease Outcomes Quality Initiative of the National Kidney Foundation (NFK-K/DOQI) targets, in a group of dialysis patients with secondary hyperparathyroidism that were not controlled with vitamin D metabolites due to inadequate elevations in serum calcium and/or phosphorus. Twenty-eight patients undergoing haemodialysis that presented secondary hyperparathyroidism (PTH > 300 pg/ml) with difficulty to use vitamin D either because of hypercalcaemia (>10.2 mg/dl) and/or hyperphosphoraemia (>5.5 mg/dl) were included in this study. The follow-up period was 9 months before and after the introduction of cinacalcet. We started by adding 30 mg of cinacalcet orally once daily to their previous vitamin D metabolite treatment. The following variables were calculated and recorded: the mean of all measurements of serum Ca, P and parathyroid hormones (PTH), and Ca x P in each patient; calcium in dialysate (mEq/l); doses of vitamin D administered; doses of cinacalcet used, and the average prescription of calcium-based phosphate binders, sevelamer hydrochloride and aluminum binders, corresponding to two periods according to the introduction of cinacalcet. The proportions of patients with different serum Ca levels as well as serum P levels; serum PTH levels and CaxP at the beginning and at the end of the nine month period of treatment with cinacalcet were calculated. Serum PTH (826.9 +/- 325 vs 248.1 +/- 77.3, P < 0.001), serum calcium (9.9 +/- 0.6 vs 8.6 +/- 0.4, P < 0.001) and the Ca x P product (94.7 +/- 7.3 vs 43.6 +/- 8.5; P < 0.001) diminished significantly whereas serum phosphorus remained unchanged (4.8 +/- 1.5 vs 4.3 +/- 1.1; P = NS). Before cinacalcet, 23 patients had severe hyperparathyroidism (serum PTH > 500) and 15 patients hypercalcaemia (serum calcium >10.2 mg/dl). After 9 months of treatment, all 28 patients showed serum PTH < 500 pg/ml and serum calcium <10.2 mg/dl; 64.7% of the patients achieved Ca, P, Ca x P and PTH objectives simultaneously. While the mean dose of cinacalcet increased along the 9 months of treatment (P < 0.001), there were no significant changes in vitamin D metabolites (P = 0.5), neither in the mean doses of calcium-containing agents, nor in the mean prescribed doses of sevelamer (P < 0.01), and aluminium-containing agents diminished significantly (P < 0.05). In summary, the combination of cinacalcet and low doses of vitamin D improved significantly the control of PTH and Ca x P in patients with severe secondary hyperparathyroidism on chronic haemodialysis, without adverse effects and with lower doses of phosphate binders.