Calcimimetics in the chronic kidney disease-mineral and bone disorder

Mineral and bone disorders (MBD) are both an early and very common complication of chronic kidney disease (CKD). It is now accepted that they represent a significant risk factor, explaining the high cardiovascular morbidity and mortality in CKD patients. During the last decade, we have been witnessing many advances in the nomenclature, classification, pathophysiology, diagnosis, and treatment of CKD and some of its complications, such as CKD-MBD. The identification of the calcium-sensing receptor (CaSR) involvement in the pathogenesis of primary and secondary hyperparathyroidism (SHPT) and the availability of a new class of drugs called calcimimetics are two outstanding examples. Cinacalcet, the only available calcimimetic, has been shown to be a very effective therapeutic tool in CKD-MBD. Many clinical trials with cinacalcet in hemodialysis patients with SHPT have shown a reduction in parathyroid hormone, calcium (Ca), phosphate (P) and Ca x P product levels, allowing far greater success in reaching therapeutic goals as recommended by international guidelines. Additionally, some studies have shown that the use of cinacalcet may improve other aspects of CKD-MBD, reducing the risk of vascular calcification and parathyroidectomy, among others. Prospective studies on dialysis patients, with hard endpoint data, are currently underway. This review summarizes the most significant aspects of calcimimimetics based on both experimental and clinical results, underlining their possibilities not only for the treatment of isolated SHPT but also for other CKD-MBD related conditions.

Dietary and pharmacological control of calcium and phosphate metabolism in dialysis patients

Chronic kidney disease-mineral and bone disorder is a new term defining a complex syndrome which underlines the need of a systemic approach to disturbances of calcium and phosphate metabolism in patients with renal failure. In recent years, the availability of new phosphorus binders and the appearance of new selective vitamin D receptor activators and calcimimetics have increased our current armamentarium and have changed previous paradigms. All these drugs can be used in combination, acting in distinct yet complementary pathways, with a resultant improvement in their individual clinical profile and reduction in secondary effects, while enhancing the achievement of clinical guideline targets. On the other hand, we should be aware that treatment costs are increasing and most of our knowledge is opinion-based. In this article, we shall consider rational recommendations on the control of calcium, phosphorus and parathyroid hormone while awaiting new evidence. We shall also briefly review some important related issues such as vascular calcification, adynamic bone disease, osteoporosis and the need of parathyroidectomy. Future guidelines may modify current recommendations, but we believe that the lack of an absolute evidence is not equivalent to the lack of awareness of the important problem which chronic kidney disease-mineral and bone disorder represents.