Bone health in children and adolescents after renal transplantation

Abstract

The basis for lifelong bone health is established in childhood and adolescence. Whereas pediatric renal transplant (RTx) patients are at risk for impaired bone mass gain and fractures, scarce data on this subject are available. We performed a cross-sectional and longitudinal study of bone health in a national cohort of 106 pediatric RTx patients (median age, 12.6 yr; median follow-up, 5.1 yr after RTx). The patients underwent clinical evaluation, DXA for BMD, and spinal imaging for vertebral fractures. In longitudinal analysis, the median lumbar spine BMD Z-score was lowest (median, -1.0) at 1 yr postoperatively but increased to a peak value of -0.2 at 5 yr. In boys, the lumbar spine BMD Z-score increased also during puberty but decreased in girls. In cross-sectional analysis, the lumbar spine, hip, and whole body BMD Z-scores were < -2 SD in 4%, 6%, and 6% of the patients, respectively. Sixteen percent had sustained peripheral fractures, and 8% had vertebral fractures. Female sex and age >15 yr (OR, 56.26; 95% CI, 5.17-611.82; p = 0.0007) as well as high plasma PTH levels (OR, 4.03; 95% CI, 1.37-11.85; p = 0.009) were significant predictors for low BMD. Three-year cumulative glucocorticoid dose, outside the immediate post-RTx years, was not associated with BMD parameters. The observed BMD results were satisfactory. However, the high (8%) prevalence of vertebral fractures warrants careful evaluation of bone health in these patients.