Determinants of bone mass in end-stage renal failure patients at the time of kidney transplantation

Abstract

Background: Patients with chronic renal failure (CRF) are at high risk of renal osteodystrophy. Our study aimed to identify predictors of bone mass and cumulative fracture rate at the time of renal transplantation (RTx). This is important since the patients experience further substantial bone loss the first month post-transplant.

Material and methods: Altogether 133 renal transplant patients were examined for bone mineral density (BMD) using dual-energy X-ray absorptiometry shortly after RTx.

Results: The patients'Z-scores were significantly lower at the time of RTx compared to the reference population (p < 0.05), 32% were osteopenic and 11% had osteoporosis. Independent predictors of low bone mass were age (p < 0.001), female sex (p < 0.001), intact parathyroid hormone (iPTH) level (p < 0.001), former transplantation (p = 0.001) and time on hemodialysis (HD) (p = 0.005). Body mass index (BMI) (p < 0.001) and physical activity (p = 0.027) were associated with high BMD. Cumulative fracture rate (29%) was associated with physical inactivity (p = 0.003), BMI (p = 0.036) and osteopenia (p < 0.001) at the time of RTx.

Conclusion: In a representative CRF population, BMD was reduced. Independent predictors of BMD were as for the general population, and uremia associated predictors were time on HD, previous transplantation and serum iPTH level. Fracture rate was high, and physical inactivity had the strongest association with fractures.