Phosphate Homeostasis in Chronic Kidney Disease with Emphasis in Peritoneal Dialysis

Hyperphosphatemia in dialysis patients is associated with adverse outcomes including bone mineral disease, increased total mortality, and cardiovascular mortality. Therefore, maintaining serum phosphate levels within limits is an important aspect of the clinical care of peritoneal dialysis patients. Unfortunately, hyperphosphatemia is commonly seen in the majority of dialysis patients, at least in the USA, despite apparent optimal dietary and pharmacological intervention and adequate dialysis. Herein, we review major aspects of body phosphate homeostasis in healthy subjects and in dialysis patients in order to provide a good background understanding for a more rational approach to manage serum phosphate. Of note, the phosphate concentration measured in blood by clinical laboratories represents a minute portion of the total body phosphate content but the only one that we can easily access at present; this aspect is discussed in detail in this review. We emphasize the curtailment not only of the total oral phosphate intake but also the intake of highly bioavailable phosphate; this, together with the right use of oral phosphate binders and appropriate dialysis, is an important tool. Emerging therapies with agents that block intestinal absorption of phosphate may offer a promising four-pronged approach to phosphate management.