[Histological classification of uremic bone disease and clinical significance of bone biopsy]

Bone biopsy was performed in 429 cases of uremic bone disease and they were classified histologically into 3 groups--high turnover 129 (30%), low turnover 102 (24%) and mixed type 198 (46%) cases. The histological features of the high turnover type were increased corrected mineralization rate (CMR) and osteoclast member and decreased mineralization lay time (MLT), while those of the low turnover type were on the contrary. In the mixed there were decrease of CMR and increase of MLT and osteoclast number. Bone aluminum positive rate was determined; it was 75% and 80% respectively in the low turnover and mixed type and 29% in high turnover. Biochemical study showed that significantly higher levels of serum PTH and alkaline phosphate in the high turnover type and low levels of serum 1,25(OH)2D3 and 25(OH)D3 in the low turnover. These results suggested that high turnover uremic bone disease is caused by secondary hyperthyroidism and low turnover mainly related to aluminum toxicity or other causes such as vitamin D deficiency.