Effect of Pamidronate on Bone Loss After Kidney Transplantation: A Randomized Trial

Background: Kidney transplantation is associated with an increased risk of bone fracture and rapid loss of bone mineral density after kidney transplantation. Study Design: Randomized controlled trial. Setting & Participants: Patients were randomly assigned to treatment (n = 46) or control (no treatment; n = 47) groups. Patients were stratified according to parathyroid hormone level and sex. Those with parathyroid hormone level less than 150 pg/mL were excluded. Intervention: The treatment and control groups received pamidronate, 1 mg/kg, perioperatively and then at 1, 4, 8, and 12 months or no treatment, respectively. All received calcium (500 mg) and vitamin D (400 units) daily. Immunosuppression was cyclosporine and prednisolone, with no difference in dosing between the 2 groups. Outcomes & Measurements: Bone mineral density was evaluated by means of dual-energy x-ray absorptiometry of the lumbar spine and hip at baseline and 3, 6, 12, and 24 months, with the primary end point at 1 year of percentage of change in bone mineral density from baseline. Clinical fractures were recorded and also evaluated by means of spinal radiographs at baseline and 1 and 2 years. Results: Pamidronate protected bone mineral density at the lumbar spine; bone mineral density increased by 2.1 % in the treatment group and decreased by 5.7% in the control group at 12 months (P = 0.001). Protection was also seen in Ward's area of the hip (P = 0.002) and the total hip (P = 0.004). There was no difference in femoral neck bone mineral density loss between the 2 groups. Fracture rates in the treatment and control groups were 3.3% and 6.4% per annum, respectively. Limitations: This study was not powered to detect differences in fracture rates. Conclusion: Pamidronate protects against posttransplantation bone loss at the lumbar spine and Ward's area of the hip. Am J Kidney Dis 53:856-865. (C) 2009 by the National Kidney Foundation, Inc.