Renal osteodystrophy in the first decade of the new millennium: analysis of 630 bone biopsies in black and white patients

Abstract

Renal osteodystrophy occurs early during loss of kidney function. There are 26 million American patients with chronic kidney disease (CKD), and almost all patients with CKD stage 5 have abnormal bone histology. Six hundred and thirty bone biopsies from adult CKD-5 patients on dialysis were evaluated by histomorphometry and analyzed using the turnover (T), mineralization (M), and volume (V) classification. There were racial differences; whites exhibited predominantly low turnover (62%), whereas blacks showed mostly normal or high turnover (68%). A mineralization defect was observed in only 3% of patients. In whites, cancellous bone volume was low, normal, or high in approximately the same number of patients, whereas in blacks, cancellous bone volume was high in two-thirds of the patients. More than 80% of blacks and whites with low cancellous bone volume had thin trabeculae owing to low bone formation. Cortical thickness was low in half the whites, whereas it was normal in three-quarters of blacks. Cortical porosity was high in 50% of whites, whereas three-quarters of blacks had high porosity. In summary, the TMV system gives relevant information. It should be expanded to include the architecture of cancellous and cortical bone. There are racial differences. Low bone volume and low bone turnover are more frequent than heretofore appreciated, whereas mineralization defects nowadays are observed rarely in adults. These findings call for an adjustment of the current therapeutic paradigm that takes into consideration race and risk of low bone volume and turnover. The latter have been shown to be associated with increased vascular calcifications.

Fig. 1

Prevalence of low, normal, and high bone turnover in black and white CKD stage 5 patients on maintenance dialysis. Significant difference in distribution (chi-square, p <.001).

Fig. 2

Prevalence of low, normal, and high cancellous bone volume in black and white CKD stage 5 patients on maintenance dialysis. Significant difference in distribution (chi-square, p <.001).

Fig. 3

Prevalence of low, normal, and high cortical thickness in black and white CKD stage 5 patients on maintenance dialysis. Significant difference in distribution (chi-square, p <.001).

Fig. 4

Prevalence of normal and high cortical porosity in black and white CKD stage 5 patients on maintenance dialysis. Significant difference in distribution (chi-square, p <.001).

Fig. 5

Prevalence of low, normal, and high trabecular thickness in CKD stage 5 patients on maintenance dialysis with low, normal, or high cancellous bone volume/tissue volume. Significant difference in distribution (chi-square, p <.001).