Impact of kidney transplantation on serum bone mineral levels and anemia – a cohort study on Egyptian children

Introduction
Disorder of bone mineral indicators and anemia are frequent morbidities in children with end stage kidney disease (ESKD) that can persist after kidney transplantation (KT). This study aims to investigate the effect of KT on bone minerals and anemia by comparing their levels before KT and at regular follow-up intervals after KT.

Material and methods
A cohort of 30 pediatric kidney transplant recipients (KTRs) was followed up at 3-month intervals for their first post-transplantation year. Review of pre-transplantation, transplantation- related data and regular measurement of serum calcium, phosphorus, alkaline phosphatase (ALP), parathyroid hormone (PTH), hemoglobin, hematocrit, iron and ferritin was performed.

Results
Serum phosphorus and PTH levels significantly decreased after KT (p < 0.001) with no significant change in calcium (p = 0.221) or ALP (p = 0.377) levels. Frequency of hyperparathyroidism significantly decreased after KT (p < 0.05) but 53.3% and 63.3% of patients had hyperparathyroidism at 6 and 12 months respectively. Parathyroid hormone did not show a significant difference at 6- and 12-month assessments after transplantation (p = 0.82). Hemoglobin level, hematocrit and serum iron significantly increased after KT (p = 0.019, 0.048 and 0.008 respectively). Frequency of phosphorus level abnormalities and anemia significantly declined after KT (p < 0.001 and 0.0356 respectively). Parathyroid hormone levels positively correlated with glomerular filtration rate (p = 0.004 and CC = 0.608). Patients on tacrolimus had less phosphorus than those on cyclosporine at 12 months (p = 0.005).

Conclusions
Successful KT in children partially normalizes bone mineral disorders accompanied with ESKD by reducing serum phosphorus levels. Hyperparathyroidism is prevalent by the end of the first post-transplantation year. Anemia does still exist after KT but to a lesser extent than pre-transplantation.