Long-term outcome of bone mineral density in children who underwent a successful liver transplantation

Background. It has previously been shown that bone mineral density (BMD) during the first year after orthotopic liver transplantation (OLT) in children with osteodystrophy increases remarkably and according to height. The effect of posttransplant factors possibly influencing bone mass in the long-term after a successful OLT in children is unknown. Methods. Eighteen patients (9 male), median age 13.3 (range 4.7-23.7) years, median time after OLT 8.3 (1.1-17.3) years were enrolled. Indications for OLT were biliary atresia (8), Alagille (3), hepatoblastoma (2), NonA-NonG acute liver failure (2), intrahepatic cholestasis, cryptogenic cirrhosis, and cholesteryl-ester disease (I each). At OLT, all were prepubertal and 12 were severely cholestatic. We recorded anthropometric data, immunosuppression, dual-energy x-ray absorptiometry (DXA), biochemical markers of bone metabolism, and liver function. Results. Six children were on steroid therapy, eight were on cyclosporine, nine on tacrolimus. Median L1 to L4 spinal BMD was 0.720 (range 0.524-1.127) g/Cm-2, Z score -0.70 (-2.2-+2.1), height Z score -0.31 (-1.83-+1.96). Median bone mineral apparent density was 0.112 (0.084-0.142) (normal value 0.10-0.14) g/cm(3). Median alanine aminotransferase level was 22 (range 11-79) IU/L, urinary free deoxypyridinolines 20.6 (7.1-62) nmol/mmol creatinine, osteocalcin 14 (2.3-45) mug/L, parathyroid hormone 51 (2-87) ng/L, Vitamin D3 67 (17-102) nmol/L. Conclusion. BMD after the first year from a successful pediatric liver transplantation is normal. Our study suggests that normal bone density in this setting is maintained for at least 1 decade.