Changes in bone mass early after kidney transplantation

Abstract

Renal transplant patients exhibit increased rates of trabecular bone fractures, probably due to glucocorticoid-induced osteopenia, which is known to occur within 6 months after kidney grafting. This mineral loss at a mostly trabecular site (lumbar spine) contrasts with a gain at the radius, which consists mainly of cortical bone. However, the early effects of kidney transplantation on the other parts of the human skeleton and the time course of these changes during the first 5 months after transplantation remain unknown. Therefore, 34 kidney transplant recipients were prospectively followed immediately after kidney grafting (12 +/- 1 days, mean +/- SEM, and then on a monthly basis up to 152 +/- 3 days) and compared with 34 normal healthy volunteers matched for age, sex, and body mass index. Bone mineral measurements of whole body (n = 34), lumbar spine (n = 32), and upper femur (n = 23) were performed using dual-energy x-ray absorptiometry (Hologic QDR 1000W). At time of transplantation, lumbar bone mineral density (BMD) and BMD of the upper femur were lower (p < 0.01) in female but not male patients compared with controls. Lumbar BMD decreased by 1.6 +/- 0.2% per month in both sexes (p < 0.01), whereas BMD of upper femur further decreased in males (p < 0.01) but only tended to decrease in females. At time of transplantation, whole-body bone area (BA), bone mineral content (BMC), and BMD were decreased by about 8, 15, and 9%, respectively, in patients compared with controls (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)