Purpose or Case Report: Bone metabolism in children who have undergone pediatric liver transplantation (pLT) can be negatively affected, particularly in the presence of biliary complications. Pediatric bone status entering adulthood is a critical determinant of bone health through adulthood. The aim of this study was to evaluate bone age (BA), a marker of skeletal maturity, and bone health index (BHI), a surrogate marker of bone density, in pLT recepients.
Methods & Materials: A total of 449 left hand radiographs of 207 patients [median age at the time of LTx: 1.1 years (IQR: 0.43; 6.8 years); female=50.2%, male=49.8%], all entered in the local LT register, were evaluated in this retrospective single-center study. Automated determination of BA-standard deviation score (BA-SDS) and BHI-SDS using the fully automated image analysis software BoneXpert™ had been performed. Data was correlated with age, sex, underlying disease (biliary atresia vs. non-biliary atresia), height percentile and plasma parathyroid hormone (PTH) for the whole cohort and the subgroup with biliary complications.
Results: Mean BA-SDS pre-LT was 0.025 ± 1.50, 0.034 ± 1.70 at year 1, -0.067 ± 1.62 at year 3 and -0.21 ± 1.63 at year 5. Mean BHI-SDS pre-LT was -1.8 ± 1.20, -1.6 ± 1.20 at year 1, -2.0 ± 1.10 year 3 and -2.2 ± 1.3 at year 5. Of the 121 patients (58.5%) with biliary complications, 66 (54.5%) received treatment with PTCD and 45 (37.2%) with ERCP. No significant differences between the groups with and without biliary complications aswell as PTCD/ERCP-therapy was found in mean BA-SDS and mean BHI-SDS at all timepoints. A significant positive correlation was observed between BA-SDS and height percentiles. Between patient age at LT and degree of BA-SDS reduction post LT, a significant negative association was observed for the change in BA-SDS. Post-transplant, PTH showed a significant inverse correlation with BA-SDS at years 3 and 5. A significant negative correlation between BHI-SDS and PTH was observed only at year 5.
Conclusions: While mean BA-SDS remained stable post-LT, mean BHI-SDS was consistently reduced and declined progressively until year 5, regardless of biliary complications, indicating decreased bone density. Further studies with larger patient cohorts are needed to determine the utility of automated BA and BHI assessment following pLT.