Bone mineral density and fracture prevalence in long-term kidney graft recipients

Background. Renal transplantation triggers an early bone loss that increases the subsequent risk of osteoporosis and fractures. Little is known about the long-term outcome of bone status and fracture prevalence several years after transplantation. Therefore, we conducted a cross-sectional evaluation of bone status to find out the frequency and predictors of osteoporotic fractures in late kidney graft patients. Methods. Changes in spinal, hip, and total body bone mineral density were assessed using a DEXA Hologic QRD 1000 scanner, and fractures were quantified in all kidney graft patients presenting for routine evaluation with a minimal follow-up of 5 years after transplantation (with a mean follow-up 8.5±3.1 years). We measured biochemical markers of bone metabolism and collected clinical and dietary intake data. Results. Fifty-nine renal graft recipients were enrolled in the study within 9 months. Osteoporosis, according to the World Health Organization definition, was observed in 31 patients (53% of the total population) and fractures occurred in 26 patients (44% of the total population and 51.6% of patients with osteoporosis). Femoral neck bone mineral density was positively correlated with patient’s weight and cyclosporin current dosage. Steroid cumulative dosage correlated only to lumbar spine Z score. Dietary calcium, serum 25 hydroxyvitamin D, parathyroid hormone, and urinary N-telopeptides excretion were normal. Conclusions. These data emphasize the substantial prevalence of osteoporosis and fractures among very long-term kidney graft recipients. Therapeutic intervention in these patients is urgently needed.