BONE LOSS AFTER ORTHOTOPIC LIVER-TRANSPLANTATION

PURPOSE: We assessed changes in body composition and bone loss followi ng liver transplantation to determine if bone loss is related to the u nderlying liver disease or to other factors such as sex, menopause, or graft rejection episodes. PATIENTS AND METHODS: Our cross-sectional s tudy component compared bone mass and body composition in 31 patients at 1 year after liver transplantation versus 33 pregraft patients with chronic liver disease. Bone mass was measured by dual energy X-ray ab sorptiometry (DXA) using anteroposterior views of the total body to de termine bone mineral content (BMC), and of the lumbar spine to assess bone mineral density (BMD). The body fat content was also determined b y DXA. Radiographs of the thoracic and lumbar spine were also obtained . In our longitudinal study component, 16 patients from the pregraft g roup underwent bone mass assessment again 1 year after transplantation . RESULTS: Graft patients and pregraft patients both had reduced lumba r spine BMD compared to age- and sex-matched normal values (P <0.001). A 4.75% increase in body fat content was observed after liver transpl antation (P <0.05). In the cross sectional study, bone mass of the spi ne and total body were not different in pre- and posttransplantation p atients. However, the longitudinal study revealed significant decrease s in spinal BMD and total body BMC, with a mean 3.5% decrease and a ra te of loss of 0.55% per month. In addition, a dramatically high preval ence (29%) of vertebral fractures was observed in grafted patients, co ntrasting with a low prevalence (8.4%) of fractures in pregraft patien ts. Menopause, primary biliary cirrhosis, and chronic alcohol abuse we re the principal contributing factors for osteoporosis. Patients with vertebral fractures had a marked 17.4% decrease of the lumbar spine BM D (P <0.001) and a 22% decrease in total BMC when compared to patients without fractures (P <0.01). CONCLUSION: Patients with orthotopic liv er transplantation for chronic liver disease evaluated 1 year after tr ansplantation have a high prevalence of vertebral fractures. Cross sec tionally, bone mass was not different in patients before and after tra nsplantation, but the longitudinal study showed that liver transplanta tion induced a marked and rapid bone loss. Bone loss due to transplant ation could enhance the risk of new vertebral fractures, as shown by t he high prevalence of vertebral fractures. These results emphasize the need to identify patients with low bone mass by bone densitometry bef ore transplantation.