[Mineral-bone disorder with chronic kidney disease]

Mineral-bone disorder in chronic kidney disease is a clinical syndrome provoked by the combination of three factors: abnormal laboratory results, bone morphology disorder and extra-bone calcification. Its onset in adult age is linked with a decrease in glomerular filtration (GF < 1 ml/s). Fully developed forms occur in the course of regular dialysis treatment. The use of the traditional denomination "renal osteodystrophy" is currently restricted to the bone morphology finding. As there are two threshold types of bone turnover (low and high) and two degrees of mineralisation (low and normal), there is a total of four basic variants of mineral-bone disorder. The high turnover variants--secondary hyperparathyreosis and a combined disorder--are still the most frequent and are diagnosed in 70 to 80% of cases. Low turnover disorders include osteomalatia (OM) and adynamic bone disease (ABD). While OM is becoming increasingly rare, the occurrence of ABD is on the rise. The main reason for this may be the steady growth in the age of dialised patients and a number of risk factors, as well as treatment with inadequately high doses of vitamin D. Progressive chronic kidney disease may be linked with D-hormone deficit, negative calcium balance and with positive phosphate balance. Phosphates become a key factor in the development and progression of secondary hyperparathyreosis and extra-bone calcification in the case of D-hormone substitution. Therefore, maintaining a good phosphate balance by restricting their intake or by reducing their intestinal resorption through the use of phosphate binders is the most efficient therapeutic procedure. In patients with chronic kidney failure, adequate dialysis treatment is necessary. Hyperphosphatemia and extra-bone calcification are new independent risk factors of cardiovascular morbidity and mortality.