Decreased Bone Mineral Density in Patients Submitted to Kidney Transplantation Is Related to Age, Body Mass Index, Time on Dialysis, and Hyperparathyroidism

Abstract

Background. Renal transplantation (Tx) influences bone mineral density (BMD) by several mechanisms. The main objective of this study was to correlate BMD and risk factors associated with bone loss in patients submitted to kidney Tx. Methods. We evaluated 88 individuals after renal Tx (median time = 31.5 months since Tx). All of them sustained glomerular filtration rate ≥60 mL/min/1.73 m2. BMD was measured by dual-energy X-ray absorptiometry (DXA, Prodigy-GE). Calcium, phosphate, albumin, creatinine, and intact parathormone (PTH) were measured at the same time. All statistical tests were two-sided and P value less than 0.05 were accepted as significant for all analyses in this study. Results. Serum PTH was raised in 42% patients, but corrected calcium was normal in 83 patients. No fragility fracture was reported, but the overall prevalence of osteoporosis was 27.6% and lower than expected BMD (Z-score ≤ −2.0 SD) was observed in 28.4%. Patients with lower than expected BMD had higher PTH levels. Conclusions. Older age, lower body mass index (BMI), longer time on dialysis, and elevated PTH levels were identified as the main factors associated with lower BMD.