Zoledronic Acid to Prevent Bone Loss After Kidney Transplantation

A Prospective and Randomized Trial of Zoledronic Acid to Prevent Bone Loss in the First Year After Kidney Transplantation

The purpose of this study is to determine whether zolendronic acid, a third generation bisphosphonate, is effective in preventing bone loss in the first year after kidney transplantation.

For the treatment of osteoporosis in the general population, a number of drugs reduce BMD (bone mineral density) loss and the rate of incident fractures. For instance, bisphosphonates improve BMD, reduce hip fracture rates and decrease mortality in post-menopausal women. Because of lack of data on safety and an increased risk of adverse effects, the use of these drugs is controversial in patients with chronic kidney disease (CKD) and abnormalities of PTH or vitamin D, an estimated glomerular filtration rate (GFR) less than 30 ml/min/1.73m² (CKD stages 4 and 5) and after transplantation. The efficacy of short and long term bisphosphonate treatment after kidney transplantation has been examined; however, histomorphometric and fracture rate reduction data are lacking. The purpose of this study is to determine whether zolendronic acid, a third generation bisphosphonate, is effective in preventing bone loss in the first year after kidney transplantation.

Intravenous administration of zoledronic acid (5 mg) in a single dose at the time of kidney transplantation and vitamin D replacement.

The control group will receive only vitamin D replacement. The aim of vitamin D replacement will be serum levels of 25 (OH) vitamin D above 30 ng/ml.

The treatment group will receive 15-minute intravenous administration of zoledronic acid (5 mg) in a single dose at the time of kidney transplantation and vitamin D replacement. The aim of vitamin D replacement will be serum levels of 25 (OH) vitamin D above 30 ng/ml.

Bone microarchitecture will be examined by high-resolution peripheral quantitative computed tomography at the time of transplant and after 12 months.

Bone mineral density (BMD) measurements by dual-energy X-ray absorptiometry (DEXA) will be made at the time of transplant and after 6 and 12 months.

Inclusion Criteria: All adult kidney transplant recipients who were stable perioperative and able to return for regular follow-up Exclusion Criteria: Glomerular filtration rate < 30 ml/min/1.73m² one week after transplantation Previous parathyroidectomy or diagnosis of adynamic bone disease (with bone biopsy)