[Effects of kidney transplantation on bone: osteoporosis or other?].

Post-transplant bone disease is a heterogeneous osteodystrophy because the effects of age, gender, persistent hyperparathyroidism, corticosteroid and calcineurin inhibitor therapy are superimposed. The decrease in bone mass is particularly prominent during the first 6 months after kidney transplantation and is associated with an increased number of fractures. Bone mineral density measurements do not predict bone histology. Bone biopsy reveals heterogeneous lesions, which differ during the early and later phases after transplant. Interestingly, the cases of osteoporosis (BV/TV <15%) are comparatively few, and biopsies in later phases show delayed mineralization as a common finding, and a generalized prevalence of osteomalacic lesions. Bone histology could be a useful tool to delineate the underlying histological alterations in such patients in order to develop adequate therapeutic strategies.