Management of metabolic bone disease in kidney transplant recipients. Am J Med Sci. 2008;335:120-125. [PMID: 18277120 DOI: 10.1097/maj.0b013e3180a5e947]

Resistance exercise training restores bone mineral density in renal transplant recipients

Background

The kidneys are complex organs of human body sustain a number of vital and important functions. These organs need to be replaced in some subjects due to various diseases. Bone mineral density (BMD) of the subjects with kidney transplantation reduced as a result of poor mobility and use of especial drugs. Due to lack of information regarding the influences of weight training exercise on BMD of long bone, this research was done.

Method

24 subjects with history of kidney transplantation were recruited in this study. They were divided into two groups who received weight training exercise and control group. The BMD of femur and lumbar spine was measured by use of dual energy X-Ray absorptiometry in both groups. The difference between BMD was evaluated by use of two sample T test.

Result

The mean values of BMD of femur were 0.679±0.09 g/cm² and 0.689±0.09 before and after exercise in this first group. In contrast it was 0.643±0.11 before follow-up and 0.641±0.11 g/cm² after follow-up in the control group. There was no difference in BMD of lumbar spine after exercise.

Conclusion

The result of this research study showed that BMD of long bone improved follow exercise. Therefore, it was concluded that weight training exercise can be used for the subjects with kidney transplantation.

Oral paricalcitol reduces the prevalence of posttransplant hyperparathyroidism: results of an open label randomized trial

Postkidney transplant hyperparathyroidism is a significant problem. Vitamin D receptor agonists are known to suppress parathyroid hormone (PTH) secretion. We examined the effect of oral paricalcitol on posttransplant secondary hyperparathyroidism by conducting an open label randomized trial in which 100 incident kidney transplant recipients were randomized 1:1 to receive oral paricalcitol, 2 μg per day, for the first year posttransplant or no additional therapy. Serial measurements of serum PTH, calcium and bone alkaline phosphatase, 24-h urine calcium and bone density were performed. The primary endpoint was the frequency of hyperparathyroidism 1-year posttransplant. Eighty-seven patients completed the trial. One-year posttransplant, 29% of paricalcitol-treated subjects had hyperparathyroidism compared with 63% of untreated patients (p = 0.0005). Calcium supplementation was discontinued in two control and 15 treatment patients due to mild hypercalcemia or hypercalcuria. Paricalcitol was discontinued in four patients due to hypercalcuria/hypercalcemia and in one for preference. Two subjects required decreasing the dose of paricalcitol to 1 μg daily. Hypercalcemia was asymptomatic and reversible. Incidence of acute rejection, BK nephropathy and renal function at 1 year were similar between groups. Moderate renal allograft fibrosis was reduced in treated patients. Oral paricalcitol is effective in decreasing posttransplant hyperparathyroidism and may have beneficial effects on renal allograft histology.

Metabolic bone diseases in kidney transplant recipients

Metabolic bone disease after kidney transplantation has a complex pathophysiology and heterogeneous histology. Pre-existing renal osteodystrophy may not resolve completely, but continue or evolve into a different osteodystrophy. Rapid bone loss immediately after transplant can persist, at a lower rate, for years to come. These greatly increase the risk of bone fracture and vertebral collapse. Each patient may have multiple risk factors of bone loss, such as steroids usage, hypogonadism, persistent hyperparathyroidism (HPT), poor allograft function, metabolic acidosis, hypophosphatemia, vitamin D deficiency, aging, immobility and chronic disease. Clinical management requires a comprehensive approach to address the underlying and ongoing disease processes. Successful prevention of bone loss has been shown with vitamin D, bisphosphonates, calcitonin as well as treatment of hypogonadism and HPT. Novel approach to restore the normal bone remodeling and improve the bone quality may be needed in order to effectively decrease bone fracture rate in kidney transplant recipients.