Persistently increased bone turnover and low bone density in long-term survivors to kidney transplantation

Aims: There are few data on the long-term outcome of bone health in renal t ransplant recipients. We wanted to evaluate the prevalence of osteoporosis and related clinical fractures in long-term survivals to kidney transplanta tion. Methods: We carried out a cross-sectional study of 80 males and 44 fe males, aged 45 +/-1 years, who had undergone kidney transplantation (KTx) 5 5.6 +/-4.6 months earlier. Patients were treated according to standard immu nosuppressive protocols. Results: High parathyroid hormone levels were obse rved in 55 out of the 124 patients (44.6%) and the prevalence of secondary hyperparathyroidism (SHPT) remained similar even when subjects were grouped according to the time elapsed since transplant. The Z scores for bone alka line phosphatase, osteocalcin, urinary N telopeptide and galactosyl-hydroxy lysine were increased as compared to normal controls, both in males and fem ales (p<0.05). Bone formation markers normalized, while bone resorption mar kers remained elevated in these patients even ten years after transplant. V ertebral and femoral osteoporosis were present in 37% and 56% of the patien ts, respectively, and no tendency toward a recovery in bone mass was seen e ven in those patients who had survived the longest time since KTx. Clinical fracture rate was 0.006 and 0.031 patient years, before and after KTx, res pectively. The number of fractures was lower in patients taking lower mean daily doses of corticosteroids (p<0.025). PTH levels positively correlated with bone alkaline phosphatase, osteocalcin and N telopeptide. Conclusion: In conclusion, bone density is decreased and bone turnover increased even m any years after KTx, with persistent SHPT and corticosteroid use being the main pathogenetic factors.