EVALUATION OF CORTICAL BONE BY PERIPHERAL QUANTITATIVE COMPUTED TOMOGRAPHY (PQCT) IN RENAL TRANSPLANT (TX) PATIENTS

P373 Background: The absolute risk of fractures in renal Tx patients is 3 times that of matched controls. Most of the symptomatic fractures are peripheral, suggesting a grater compromise of cortical bone. Peripheral QCT is a new imaging technique that allows the non-invasive evaluation of cortical and trabecular bone separately. Aims: We investigated cortical bone by pQCT in 12 renal transplant patients (7 males and 5 females); comparisons were made with 28 normal controls. Methods: Peripheral QCT (XCT 960, Stratec, Pforheim, Germany) was performed at proximal radius of the non-dominant forearm (15% the length of the ulna from endplate) We evaluated Total and cortical bone mineral density (TBMD,cBMD), Total (cross-sectional) and cortical area (TA, cA), cortical thickness (cThk), endosteal and periosteal perimeters and buckling ratio[r/cThK]. Results: Female Tx patients had a marked decrease in cA: 51,4 vs 69,3 (pixel n; p<.0001) and cThK: 2,08 vs 2,78 mm (p<.0001). Male Tx patients had also a decrease in cThK : 2.54 vs 3,30 mm (p=.0001) and an increase in endosteal perimeter (31.2 vs 26.4 mm; p<.0001) Conclusions: Our results show a marked thinning of cortical bone that could explain the increased incidence of peripheral fractures in renal Tx patients.