Significance of calcium phosphorus product
What is the calcium phosphorus product and what is its significance?
The term calcium-phosphorus product (Ca x P) was first coined in 1922 by Howland and Kramer, attempting to explain risk factors for children who developed rickets. A few years later, this concept was tied to ectopic calcification—calcification that happens outside of bone. It was presumed that this simple second-order relationship was representative of intravascular calcification and, consequently, could be tied to outcomes, especially in dialysis patients. Despite ectopic calcification being an established risk factor for outcomes in dialysis patients, the calcium-phosphorus product could not be established as a risk factor for ectopic calcification, and altering this product did not impact outcomes. Consequently, this concept has fallen out of favor.