New aspects of treatment of renal bone disease in dialysis patients.

The abnormalities in bone and mineral metabolism in chronic kidney disease patients are associated with an increased risk of fractures, vascular calcifications and cardiovascular diseases. A few decades ago hyperphosphatemia and the common development of secondary hyperparathyroidism were thought to be the main problem to deal with. Since dietary phosphate restriction and haemodialysis were not proven to be sufficient measures to reduce phosphorus, phosphate-binding therapy has been widely instituted as a treatment option. Various types of phosphate binders employed over the years have contributed to the changing spectrum of renal osteodystrophy from high to low bone turnover along with the shift from hypocalcemia and negative calcium balance towards hypercalcemia and the positive calcium balance. Thus, hypercalcemia instead of hyperphosphatemia is nowadays associated with the increased risk of vascular calcification, morbidity and mortality in the dialysis population. Besides the very expensive non-calcium based phosphate binders, at least two common tools may be helpful in the treatment of hypercalcemia and adynamic bone. A reduced daily use of calcium carbonate/acetate up to 1g per main meal is an easily manageable and inexpensive tool. The second option for stimulation of parathyroid gland activity and bone turnover is the lowering of the dialysate calcium concentration. In conclusion, an aggressive treatment of hyperphosphatemia and calcium overload might lead towards an opposite effect of hypoparathyroidism and hypercalcemia. Reasonable treatment strategies based on a careful monitoring should be employed in order to prevent related consequences and to contribute to a better long-term quality of life and survival of dialysis patients.