Correlation of bone mineral density with the histological findings of renal osteodystrophy in patients on hemodialysis.

AIMS: To examine the distribution of bone mineral density (BMD) in different histological groups of renal osteodystrophy.

PATIENTS: We prospectively studied 62 patients, 41 men and 21 women, aged 57+/-11.5 years, who had been on hemodialysis for 60+/-55 months. The women had been amenorrheic for 13+/-4 years and 7 patients (11%) had a positive fracture history.

METHODS

A bone biopsy was taken after tetracycline labelling and BMD of the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DEXA); serum intact parathyroid hormone (iPTH), bone Gla protein (BGP), phosphorus, calcium and alkaline phosphatase (ALP) were also determined.

RESULTS

Histologically, 40 patients showed secondary hyperparathyroidism (sHPT), 6 mixed bone disease, 14 adynamic bone disease (A) and 2 osteomalacia. BMD of the lumbar spine was decreased in 43 patients (69%) and in 9 (14.5%) it was lower than -2 Z score units. BMD of the femoral neck was low in 55 patients (89%) and in 22 (35.5%) it was lower than -2 Z scores. BMD was lower in patients with sHPT than in those with adynamic bone disease (p<0.05) in which it was close to normal. BMD in both these sites correlated inversely with the biochemical markers (serum iPTH, BGP and ALP) and the histomorphometric indices of bone turnover.

CONCLUSIONS

Osteopenia is frequent in patients on hemodialysis, especially those with biochemical and histological findings of sHPT.