[A study using nondecalcified bone biopsy of the incidence and presentation forms of renal osteodystrophy]

Renal osteodystrophy (ROD) is a common complication of chronic renal failure. Fibrous osteitis and, to a lesser extent, osteomalacia are the predominant lesions. The aim of the present study was to evaluate the prevalence of the different forms of ROD.

Nondecalcified bone biopsies were evaluated in 100 patients with end-stage renal disease (57 in pre-dialysis and 43 on hemodialysis) in whom biochemical (calcium, phosphorus, alkaline phosphatase, parathyroid hormone) and histomorphometric studies were carried out. Bone biopsies were classified in four histological groups: mild, fibrous osteitis (FO), osteomalacia (OM) and mixed type (FO + OM).

96% of patients had histological findings of ROD with the following distribution: 41% mild; 30% FO; 14% OM; and 11% mixed. The most advanced types of ROD were seen in interstitial renal diseases. Pre-dialysis OM was associated with metabolic acidosis, a low phosphocalcic product and relative hypophosphoremia. Chronic aluminium poisoning was uncommon (7%) and was basically associated with OM. No instance of aluminium poisoning with osteodystrophy and bone fractures was seen.

The most severe histological forms of OM were found in hemodialysis patients with persistent hypophosphoremia and associated with osteosclerosis.