Post-transplantation osteoporosis is influenced by multiple factors. An important risk factor for bone morbidity is rappresented by persistent secondary hyperparathyroidism (PTH >65 pg/ml). From a large cohort of patients who had undergone kidney transplantation, we selected 125 caucasian patients (87 males and 38 females), who had undergone
kidney transplantation 0 to 10 year before, aged 25-65 years, with serum creatinine < 228 ?mol/L. All patients underwent an evaluation of the main biochemical parameters of bone metabolism as well as bone densitometry. In 87 patients we also studied three polymorphism of the Calcium-sensing receptor (A986S, R990G, Q1011E). PTH levels higher than 65 pg/ml were found in 68 % of the patients.
Surprisingly, 40 % of the patients presented 25-OHvitaminD values ? 30 nmol/L (deficiency), 56,8 % values between 30 and 80 nmol/L (insufficiency) and only 3,2 % values >80 nmol/L (normal range). The proportion of patients with osteoporosis was 25,6 % at the spine, 7,2 % at total femur and 16,8 % at femoral neck. Bone density resulted lower in patients who had been treated with dose of glucocorticoid higher than 6,7 mg/day. As regard to vertebral fractures, we observed
that 57 % of the patients had one or more vertebral fracture. In a logistic regression model only PTH levels were predictors of vertebral fracture. Multiple linear regression demostrated that 25-OH vitamin D levels, cumulative glucocorticoid intake, time on dialysis, age and time since transplantation were significantly predictive of persistent hyperparathyroidism.
As regard to CaSR polymorphism, A986S, R990G, Q1011E were
observed in 35,6 %, 11,5 % and 1,1 % of the patients, respectively.
The study did not demonstrate a significant influence of any of the three genetic variants on PTH levels, bone mass or fractures.
We conclude that osteoporosis and persistent secondary
hyperparathyroidism are common in renal transplant patients.
Low 25-OH vitamin D concentrations may exacerbate secondary
hyperparathyroidism. Treatment with vitamin D could be effective for the prevention of post-transplantation bone loss
