Persistently increased bone turnover and low bone density in long-term survivors to kidney transplantation.
OBJECTIVE
There are few data on the long-term outcome of bone health in renal transplant recipients. We wanted to evaluate the prevalence of osteoporosis and related clinical fractures in long-term survivals to kidney transplantation.


METHODS
We carried out a cross-sectional study of 80 males and 44 females, aged 45 +/- 1 years, who had undergone kidney transplantation (KTx) 55.6 +/- 4.6 months earlier. Patients were treated according to standard immunosuppressive protocols.


RESULTS
High parathyroid hormone levels were observed 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 alkaline phosphatase, osteocalcin, urinary N telopeptide and galactosyl-hydroxylysine were increased as compared to normal controls, both in males and females (p < 0.05). Bone formation markers normalized, while bone resorption markers remained elevated in these patients even ten years after transplant. Vertebral and femoral osteoporosis were present in 37% and 56% of the patients, respectively, and no tendency toward a recovery in bone mass was seen even 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, respectively. 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.


CONCLUSIONS
In conclusion, bone density is decreased and bone turnover increased even many years after KTx, with persistent SHPT and corticosteroid use being the main pathogenetic factors.
Giannini
S
S
Department of Medical and Surgical Sciences, University of Padova, Italy. sandro.giannini@unipd.it
D'Angelo
A
A
Carraro
G
G
Antonello
A
A
Di Landro
D
D
Marchini
F
F
Plebani
M
M
Zaninotto
M
M
Rigotti
P
P
Sartori
L
L
Crepaldi
G
G
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000187:drug effects / Q000502:physiology*; D001842:Bone and Bones / Q000098:blood supply* / Q000187:drug effects / Q000378:metabolism*; D002117:Calcitriol / Q000502:physiology; D003404:Creatinine / Q000097:blood; D003430:Cross-Sectional Studies; D016572:Cyclosporine / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D007668:Kidney / Q000098:blood supply / Q000187:drug effects; D007676:Kidney Failure, Chronic / Q000378:metabolism / Q000601:surgery; D016030:Kidney Transplantation; D008297:Male; D008775:Methylprednisolone / Q000627:therapeutic use; D008875:Middle Aged; D008903:Minerals / Q000378:metabolism; D015675:Osteocalcin / Q000032:analysis; D010281:Parathyroid Hormone / Q000502:physiology; D015995:Prevalence; D012737:Sex Factors; D013223:Statistics as Topic; D017741:Survivors; D013997:Time Factors
D015415:Biomarkers; D007166:Immunosuppressive Agents; D008903:Minerals; D010281:Parathyroid Hormone; D015675:Osteocalcin; D016572:Cyclosporine; D003404:Creatinine; D002117:Calcitriol; D008775:Methylprednisolone