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

Abstract

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.