Evolution of bone disease in patients during the first 2 years after transplantation; a prospective single centre study

Background: Post-transplant bone disease is caused by renal osteodystrophy
acquired during HD, immunosuppressive drugs and metabolic factors after transplantation. Aim: to examine bone mineral density (BMD) and to identify factors preventing bone loss in patients in the first 2 years post transplant.
Material/Methods: 90 renal allograft recipients (age 42.7±11.4 years), treated with cyclosporine/tacrolimus, azathioprine/MMF and prednisone were included in the study. BMD measurements in lumbar spine and femur (femoral neck, Ward's and Trochanteric region) were performed by DEXA in the third month
and every 6 months for 2 years after transplantation. Markers of bone remodelling (intact parathyroid hormone [iPTH], calcitriol, osteocalcine, carboxyterminal telopeptide of type-I collagen) were assayed on the third day, 1[sup]st[/sup] month and every 6 months.
Results: In the initial measurement, osteopenia was found in 35% in the lumbar region and 52% in femur; osteoporosis in 8.3% (according o the WHO classification). Prevalence of osteopenia increased during the first year, then decreased to initial value, but the frequency of osteoporosis did not change (8.3 vs. 6.0%). BMD and Z-score decreased during first and increased in the second year; 27% patients achieved initial values and 38% higher than initial values. BMD gain in lumbar spine and femur was found in patients with significantly higher calcitriol level during first six months (P<0.01); higher osteocalcin level (P<0.05); higher eGFR during 1 to 24 months and treated with tacrolimus. Improvement of lumbar BMD occurred in younger patients (38 vs. 46 years; P<0.027). BMD gain in femur correlated with higher level of iPTH from 1-12 months (P<0.01);. Patients treated with tacrolimus had significantly higher Z-score in lumbar spine and femur at 24 month in comparison to cyclosporine treatment (p<0.05).
Conclusions: Two years after transplantation >60% of patients showed stability or gain in the bone mass. Sufficient calcitriol level in early post transplant period, adequate iPTH, renal efficiency and tacrolimus treatment prevent progression of the post-transplant bone disease.

Keywords: Immunosuppression, Kidney Transplantation