New worldwide trends in presentation of renal osteodystrophy and its relationship to parathyroid hormone levels.

AIMS

Abnormal mineral metabolism in chronic renal disease is associated with bone disease and extraskeletal calcifications. High turnover, hyperparathyroid bone disease, the most common form of renal osteodystrophy, has been the target for aggressive therapy. More recently, an increasing occurrence of low turnover bone disease has been reported. The present study was undertaken to evaluate the current prevalence of different forms of bone disease in a large population on chronic hemodialysis and its relationship to parathyroid hormone (PTH) levels.

METHODS

Ninety-six chronic hemodialysis patients underwent double tetracycline-labeled bone biopsy. Serum PTH levels were obtained in 52 patients at the time of biopsy. Bone formation rate (BFR/BS) was plotted vs. PTH levels in all patients and in subgroups with PTH ranges between 0-150, 150-500 and 500 - 1,200 pg/ml.

RESULTS

The histomorphometric data showed that 40% of all patients were affected by osteitis fibrosa cystica (OFC). In the remaining 60%, various forms of low-turnover bone disease were observed. There was no correlation between PTH and BFR/BS in all patients (r = 0.28) and in subgroups whose PTH levels ranged between 150 - 500 and 500 - 1,200 pg/ml (r = 0.027, r = 0.21), respectively. A close correlation between PTH and BFR/BS (r = 0.84, p < 0.05) was found only in the subgroup with a PTH level ranging low-turnover bone disease. The predictive between 0 - 150 pg/ml.

CONCLUSIONS

The histomorphometric findings present a wide spectrum of renal osteodystrophy with a shift towardsvalue of PTH is limited as high-turnover osteodystrophy may present with low PTH levels and that with low turnover may occur with high PTH levels. In the latter parathyroidectomy should be avoided. We share the view that bone biopsy remains the "gold standard" diagnostic tool for renal osteodystrophy.