The degree of bone mineralization in chronic renal failure estimated from phosphorus/hydroxyproline ratio in bone biopsies.

The degree of bone mineralization is the proportion between the contents of mineral and collagen in bone. As phosphorus (P) and hydroxyproline (Hypro) constitute a constant fraction of bone mineral and collagen, respectively, the P/Hypro ratio in bone tissue provides an estimate of the degree of mineralization. The P/Hydro ratio has been studied in bone biopsies from 42 patients with severe chronic renal failure. A few of them had a subnormal P/Hypro ratio and these patients corresponded to the diagnosis of classical osteomalacia or probably hyperparathyroidism. However, the mean bone P/Hypro ratio was significantly higher than normal, indicating a general tendency towards a higher degree of bone mineralization in patients with chronic renal failure.