Parathyroid hormone and bone metabolism in kidney-transplanted patients

Background: Decreases in bone mass and increased susceptibility to fracture s are well-recognized complications in organ transplants. Subjects and meth ods: We performed a cross-sectional study on 60 patients (40 males, 20 fema les, mean age 43.2 +/- 1.06, SE range 22 - 70) who underwent kidney transpl antation (KTX) 55.6 +/- 4.5 months before. Blood and 24-hour urine samples were analyzed for the main parameters of mineral metabolism, and also for o steocalcin (BGP), bone alkaline phosphatase (b-ALP, urine N-telopeptid (u-N Tx) and urine galactosyl-hydroxylysine (u-Ghyl). DEXA scan of the lumbar sp ine (LS) and proximal femur (PF) and ultrasound determination of the heel ( stiffness) was also performed. Results: T-score values for bone density (BD ) were 2.14 +/- 0.11 SD's for LS, -2.56 +/- 0.09 for PF and 2.49 +/- 0.15 f or stiffness. There were 29 peripheral fractures in 16 patients. The rate o f fractures before KTX were 0.0011 per patient/year and 0.0005 after transp lantation fp < 0.02). When expressed as number of SD's with respect to norm al controls, BCP (1.48 +/- 0.23), b-ALP (0.95 +/- 0.19), u-NTx excretion co rrelated negatively with ED at the femoral neck (p < 0.02) and trochanter ( p < 0.03). Cumulative steroids intake were negatively correlated with b-ALP positively (p < 0.05). Current CsA was positively correlated with b-ALP (p < 0.001). Both cumulative steroid (p < 0.02) and CSA (p < 0.01) intakes we re negatively correlated with ED at Wards triangle. Conclusions:Our data de monstrate an important bone depletion at each stage KTX. PTH plays a major role in the observed increase in bone turnover, exacerbating the negative e ffects on the bone on immunosuppressive treatment. Glucocorticosteroid ther apy is an important risk factor for osteoporosis in this setting also.