Interventions for preventing bone disease in kidney transplant recipients

Approach to the patient with transplantation-related bone loss

Transplantation is an established therapy for end-stage diseases of the kidney, endocrine pancreas, heart, liver, lung, intestines and for many hematological disorders. Current immunosuppressive regimens with glucocorticoids and calcineurin inhibitors produce excellent patient and graft survival rates. This has resulted in both increases in transplant numbers and an increased recognition of previously neglected long-term complications of transplantation such as fractures and osteoporosis. Both pretransplantation bone disease and immunosuppressive therapy result in rapid bone loss and increased fracture rates. Patients are particularly at risk early after transplantation. The bone health of candidates for organ transplantation should be assessed with bone densitometry of the hip and spine. Spinal x-rays should be performed to diagnose prevalent fractures. Any secondary causes of osteoporosis should be identified and treated. Vitamin D deficiency should be corrected with vitamin D doses selected to achieve a serum 25-hydroxyvitamin D concentration of at least 20 ng/ml. All patients should receive calcium. Patients with kidney failure should be evaluated and treated for chronic kidney disease-mineral and bone disorder, including renal osteodystrophy. Secondary hyperparathyroidism, in particular, should be treated. Treatment is indicated in the immediate posttransplantation period irrespective of bone mineral density because further rapid bone loss will occur in the first several months after transplantation. Long-term organ transplant recipients should also have bone mass measurement and treatment of osteoporosis. Oral and iv bisphosphonates are the most promising approach for the management of transplantation osteoporosis. Active vitamin D metabolites may have additional benefits in reducing hyperparathyroidism, particularly after kidney transplantation.

Bisphosphonates in chronic kidney disease; balancing potential benefits and adverse effects on bone and soft tissue

Cardiovascular disease is highly prevalent in chronic kidney disease (CKD) and is often associated with increased vascular stiffness and calcification. Recent studies have suggested a complex interaction between vascular calcification and abnormalities of bone and mineral metabolism, with an inverse relationship between arterial calcification and bone mineral density (BMD). Although osteoporosis is recognized and treated in CKD 1 to 3, the interpretation of BMD levels in the osteoporotic range is controversial in CKD 4, 5, and 5D when renal osteodystrophy is generally present. In addition, there is a paucity of data for patients with CKD mineral and bone disorder (MBD), because studies using bisphosphonates in postmenopausal and glucocorticoid-induced osteoporosis have generally excluded patients with significant CKD. For these patients, treatment of low BMD using standard therapies for osteoporosis is not without potential for harm due to the possibility of worsening low bone turnover, osteomalacia, mixed uraemic osteodystrophy, and of exacerbated hyperparathyroidism; and bisphosphonates should only be used selectively and with caution. Some experimental and clinical studies have also suggested that bisphosphonates may reduce progression of extra-osseous calcification and inhibit the development of atherosclerosis. The authors review the potential benefits and risks associated with bisphosphonate use for bone protection in CKD, and assess their effect on vascular calcification and atherosclerosis.

Calcitonin for metastatic bone pain

BACKGROUND

Pain is the most frequent symptom experienced by cancer patients, its intensity dependent on the site of the tumour. Tumours that compromise bone or nervous structures due to the bone destruction process are the most painful. There are several treatments to deal with pain (and other symptoms) caused by bone metastases. The hormone, calcitonin, has the potential to relieve pain, and also retain bone density, thus reducing the risk of fractures. This review is an update of a previously published review in The Cochrane Library (Issue 3, 2003) on this topic.

OBJECTIVES

To assess the effectiveness of calcitonin in controlling metastatic bone pain and reducing bone complications (hypercalcemia, fractures and nerve compression) in patients with bone metastases.

SEARCH STRATEGY

Electronic searches were performed in MEDLINE (1966 to 2005), EMBASE (1974 to 2005), the Cochrane Central Register of Controlled Trials (Issue 2, 2005), specialised registers of the Cochrane Cancer Network and of the Cochrane Pain, Palliative and Supportive Care Group. Registers of clinical trials in progress were also searched.

SELECTION CRITERIA

Studies were included if they were randomised, double-blind clinical trials of patients with metastatic bone pain, treated with calcitonin, where the major outcome measure was pain, assessed at four weeks or longer.

DATA COLLECTION AND ANALYSIS

Study selection and data extraction were performed by two independent review authors. Only two studies (90 patients) were eligible for inclusion in the review and therefore meta-analysis of the data was not possible. Intention-to-treat analysis was performed by imputing all missing values as adverse outcomes.

MAIN RESULTS

Of the two small studies included in the review, one study showed a non-significant effect of calcitonin in the number of patients with total pain reduction (RR 2.50; CI 95%, 0.55 to 11.41). The second study provided no evidence that calcitonin reduced analgesia consumption (RR 1.05; CI 95%, 0.90 to 1.21) in patients with painful bone metastases. There was no evidence that calcitonin was effective in controlling complications due to bone metastases; for improving quality of life; or patients' survival. Although not statistically significant, a greater number of adverse effects were observed in the groups given calcitonin in the two included studies (RR 3.35, CI 95%, 0.72 to 15.66).

AUTHORS' CONCLUSIONS

The limited evidence currently available does not support the use of calcitonin to control pain from bone metastases. Since the last version of this review, none of the new relevant studies have provided additional information on this treatment, in contrast to other therapeutic approaches that should be considered.