Calcium supplementation and its effect on bone loss in renal transplant recipients.

Today, there are approximately 800 patients with kidney transplants at the Royal Adelaide Hospital and The Queen Elizabeth Hospital combined. Bone density decreases both before and after transplantation. Fracture prevalence after kidney transplant is between 7 and 60%, with fracture risk up to four times higher in this group when compared with the normal population. Potential causes for low bone density and an increased rate of bone loss are: Hyperparathyroidism (overactive parathyroid glands). This can occur as a consequence of poor vitamin D levels. If this persists, the parathyroid glands may become permanently overactive leading to elevated parathyroid hormone (PTH) levels. Poor calcium absorption from the gut. Low Vitamin D levels. Drugs which prevent transplant rejection, particularly prednisolone. Hyperparathyroidism is of particular interest in this study, as it is a common finding in patients after kidney transplant. In these patients it has been associated with increased rates of bone loss as measured by markers of bone turnover and decreased bone mineral density. Moreover it is well established that in healthy elderly adults, increased markers of bone turnover is a risk factor for fractures. Postmenopausal women are known to have an increased rate of bone loss and have a mildly increased PTH level compared to premenopausal women. Previous studies showed that an oral calcium supplement reduced hyperparathyroidism and bone loss in this group. Based on these findings in postmenopausal women, and the need for better evidence based management of bone disease in kidney transplant patients, we will study the effect of an oral calcium supplement in patients with kidney transplants. We predict that supplemental calcium will be a simple, well-tolerated and safe treatment to help maintain bone health in these patients.