Cross-sectional analysis of renal transplantation osteoporosis

We report a cross-sectional study of 54 adult female renal transplant recip ients, We measured bone mineral density (BMD) of the lumbar spine, femoral neck, total hip, and mid- and total radius, and 38 patients underwent trans iliac crest bone biopsy. Osteopenia was widespread with 31/54 (57%) of pati ents osteoporotic at one or more sites. Seventeen out of 54 (32%) of the pa tients had a prevalent low-trauma fracture. There was a clear trend in BMD reduction across spine, hip and midradius, with the predominantly cortical midradial site showing the greatest loss. We found no relationship between BMD and body mass index, parathyroid hormone (PTH), dose of immunosuppressa nt, years since transplantation, age at menopause, or years since menopause . Histologically, abnormal biopsies could be classified into three categori es: hyperparathyroid (n = 20), adynamic (n = 14), and osteomalacic (n = 2), Mean PTH was lower (p = NS) and mean cumulative prednisolone dose was high er (p = 0.04) in the adynamic group compared with the hyperparathyroid grou p, but because of overlap between groups neither was an effective discrimin ator of histology, We suggest that bone biopsy is indicated in these patien ts to direct appropriate treatment. At the cellular level, there were signi ficant negative correlations between osteoclast function (eroded surface, r = 0.47, p = 0.003) and osteoblast numbers (osteoblast surface, r = -0.40, p = 0.01) and cumulative exposure to prednisolone, We postulate that suppre ssion of osteoblast function by prednisolone with unopposed bone resorption may result in relative hypercalcaemia and low PTH, This progressive reduct ion in bone turnover may promote or prolong the adynamic state.