Loss of Regional Bone Mineral Density in the First 12 Months following Renal Transplantation

Abstract

A high incidence of osteopenia is likely in renal transplant recipients in whom pre-existing uraemic osteodystrophy, persisting hyperparathyroidism and glucocorticoids constitute a formidable array of risk factors. The correction of some biochemical and hormonal abnormalities, an increase in body weight and an increase in physical activity following transplantation could favour improvements in skeletal integrity. Using dual energy X-ray absorptiometry (DEXA), we studied prospectively the regional bone mineral density (BMD) of 34 consecutive cadaveric renal allograft recipients who were already established on dialysis. BMD of these patients was measured at the time of transplantation and was repeated at 3, 6 and 12 months following the transplantation. Immunosuppression was achieved using triple therapy: azathioprine, cyclosporin-A and prednisolone. At baseline, total BMD and BMD at the lumbar spine and femoral neck did not differ from age- and sex-matched controls. Females experienced marked and progressive bone loss at the lumbar spine, with less marked changes at the femoral neck. Males, in contrast, experienced substantial reduction of BMD at the femoral neck at 6 months and a recovery at 12 months without significant change at the lumbar spine. Whole body bone mineral content fell transiently in males, with partial recovery by 6 months. No significant correlation was found with the cumulative doses of either corticosteroids or cyclosporin-A, the duration of hospitalisation, the function of the transplant, patient age or menopausal status. In females the loss of BMD at the lumbar spine at 6 months was closely associated with a high parathyroid hormone level (PTH) at transplantation, and in males, the loss of BMD at the femoral neck was associated with a low PTH level at transplantation. We conclude that rapid falls in BMD appear to be inherent to the process of renal transplantation and that strategies to prevent this loss should be evaluated.

Bone Disease after Renal Transplantation

“…Julian et al (1) found that after 6 mo after transplantation, there was a sharp decrease in lumbar spine BMD by almost 7%, with a further decrease, reaching up to a 9% loss, at 18 mo. Similarly, Almond et al (2) found a 3.9% decrease in femoral neck BMD in male transplant recipients at 3 mo after transplantation. More recently, Mikuls et al (3) in a prospective study showed within 6 mo of transplantation a loss of a mean of 2.4% BMD at the lumbar spine with no significant decline at the femoral neck in more than one third of the patients.…”

Fibroblast Growth Factor-23 and Parathyroid Hormone Are Associated with Post-Transplant Bone Mineral Density Loss

“…Previous studies have yielded conflicting data on the significance of pretransplant PTH levels as a predictor of posttransplant BMD loss: both high (20,(27)(28)(29) and low (15) pretransplant PTH levels have been correlated with BMD loss. Similar to FGF-23, pretransplant PTH levels are directly associated with post-transplant levels (7).…”

Preventing Bone Loss in Renal Transplant Recipients with Vitamin D

“…Metabolic parameters at baseline and after 12 mo of treatment initial transplantation, but this reduction of bone mass is more evident in the first 6 mo (2,3). The onset of bone loss has been attributed mainly to immunosuppression therapy and in particular to corticosteroids (2,3). However, despite the use of lower maintenance doses of corticosteroids, as a result of the use of CsA, a decrease of early posttransplantation bone loss has not been observe as a result of an imbalance in bone remodeling consistent with the toxic effects of steroids (3).…”

“…Short-term studies of bone loss after renal transplantation have indicated rapid bone loss within the first 6 to 18 mo after grafting (2,3). However, others have suggested a continuous demineralization process in long-term renal transplant recipients (4).…”