Dual-photon bone densitometry in dialyzed patients

In non-invasive diagnosis of renal osteodystrophy the levels of bone minerals and the extent of bone turnover are evaluated. The contents of bone minerals are assessed quantitatively by different modalities of bone densitometry, among which the most accurate one is double-energy bone densitometry. So far no standard examination method was defined nor the most suitable portion of the skeleton for densitometric examination. In order to find such an area and also to assess the prevalence of bone demineralization, its severity and regional differences the authors made a cross-sectional study of bone density in dialyzed patients. The group comprised 45 patients, 24 men and 21 women subjected to regular dialyzation treatment for 20-24 months. In a lambda whole body bone densitometry was performed with evaluation of regional densities of the trunk, upper and lower extremities. At the same time the state of bone turnover was assessed arbitrarily using values of serum concentrations of intact parathormone; parathormone concentrations below 50 pg/ml were considered low, above 200 pg/ml high and concentrations within the mentioned range as the normal bone turnover. In the group of patients 62% had a high, 22% a normal and 16% a low bone turnover. The study provided evidence of a significant reduction of bone density (Z score <-1) in 58% of patients. In 92% of patients demineralization affected most and first the extremities. In 69% it affected the lower extremities and in 23% the upper ones. 8% of the patients had the most severe affections in the area of the trunk. This order of affliction was not influenced by bone turnover, sex and in women by age. The diaphysis of long bones seems to be a representative examination area of the skeleton for densitometric measurements in patients with regular dialyzation treatment.