An update on calcium metabolism alterations and cardiovascular risk in patients with chronic kidney disease: questions, myths and facts.

In 2006, the Kidney Disease Improving Global Outcomes (KDIGO) guidelines introduced, for the first time, the definition and diagnostic and therapeutic criteria for a systemic complication of the mineral metabolism dysfunction, such as vascular calcification, caused by chronic renal insufficiency. Abdominal x-ray and echocardiography rather than the more complex CT scan is suggested to make the diagnosis. This condition is associated with high cardiovascular risk and consequent poor prognosis. An alteration in total body calcium (Ca) content is one of the key factors in the cardiovascular complications observed in uremic subjects. In the general population, the addition of Ca to the diet has been to shown to improve bone mineral density (BMD) compared to controls, but it does not appear to reduce the risk of bone fractures. In patients with CKD, there are certainly some theoretical justifications for administering calcium salts: vitamin D deficiency, which reduces the intestinal absorption of Ca; hypocalcemia, which increases the risk of hyperparathyroidism; and hyperphosphatemia, which justifies the use of Ca-based P binders. There is already a large body of evidence pointing against the use of Ca-based binding agents, when there is a positive Ca balance because of the development of vascular calcification.