Calcimimétiques : physiologie, résultats d’études cliniques et perspectives

[Clinical and biological forms of secondary hyperparathyroidism in dialysis patients]

The diagnosis and treatment of hyperparathyroidism (HPT) are not yet well standardized in chronic renal failure patients. The aim of this study was to identify the main types of HPT on the basis of clinical and biological findings in a haemodialysis population. Between 2004 and 2010, all patients undergoing haemodialysis were observed and treated using the same strategy: conventional therapy with vitamin D supplements, phosphate binders, dialysate calcium adjusted to serum parathyroid hormone (PTH) level and calcitriol analogues (CA), along with regular bone marker analysis. Wherever required, cinacalcet (CC) was administered and parathyroidectomy (PTX) was performed. Of the 520 patients, 158 were classified as having HPT (30%) with a serum PTH level greater than 300 pg/mL. From this population, we identified five main types of HPT: (1) HPT with 'no bone impact' had normal or low bone marker levels (n=28, 17.7%); (2) 'secondary' HPT had elevated bone marker levels, but showed favorable response to CT (n=59, 37.7%); (3) 'tertiary' HPT was accompanied with hypercalcemia and required CC or PTX in case of CT failure (n=11, 6.9%); (4) 'mixed' HPT could not be completely treated with CT and required CC or PTX (n=57, 36%); (5) 'resistant' HPT did not show hypercalcemia, but required PTX after CT and CC failure (n=3, 1.8%). CC was prescribed in 51% cases, CA in 76%, and PTX in 7% of cases. We typified HPT on the basis of physiopathology and stages of HPT progression. Further studies on HPT that focus on bone marker levels are required to establish well-defined treatment strategies. In our study, HPT cases did not show uniform findings in Hémodialyse (HD) patients because of the variation in the stages of the disease at the time of diagnosis.