ESPE Abstracts

Third generation AIs have been repurposed as an off-label treatment in boys and girls, as they can retard closure of the epiphysial plate expanding the period of growth. Assessment of digital hand X-rays has introduced new follow-up indexes of bone health: Bone Health Index (BHI) from DICOM files describes bone mass as a function of cortical thickness, and Metacarpal Index (MCI) from digitized files expresses the cortical thickness standardized for the outer bone diameter at the measuring site, measured in SDS for the relevant bone age (BA). BHI/MCI SDS were evaluated in 275 children on AIs, 181 boys, 94 girls, before and at 6-month intervals for 18 months, to investigate any effect on bone health. In all patients a normal calcium metabolism: 25OHD > 30 ng/ml and PTH < 45 pg/ml was assured. Anonymous laboratory and somatometric data were used from patients recorded in Growth Analyser EPRS software. BHI/MCI were assessed by BoneXpert (Visiana, Denmark). BHI of boys was -0.84±1.08 at the beginning of treatment and remained unchanged at -0.84±1.13 after 18 months (P = 0.5). In girls, BHI was -0.75±1.25 at the start of treatment and decreased to -1.24±1.05 after 18 months but without statistical significance (P = 0.06). The initial MCI of boys -1.06±1.14 showed a statistically significant increase after 12 months, rising to -0.73±1.02 (P = 0.04), and continued to improve to -0.62±1.02 after 18 months of treatment (P = 0.03). In girls, the initial MCI was -0.87±1.19 and slightly increased to -0.81±1.26 after 18 months, but this change was not statistically significant (P = 0.4). The average combined index BHI/MCI for boys was -0.92±1.11 at the beginning of treatment, improving to -0.73±1.08 after 18 months, though this change was not statistically significant (P = 0.1). For girls, the combined index was -0.82±1.20 initially, decreasing to -1.0±1.16 after 18 months, without statistical significance (P = 0.2). We also compared the average combined index BHI/MCI between boys and girls at the beginning of treatment: boys: -0.92±1.11, girls: -0.82±1.20; P = 0.2, and at 18m: boys: -0.73±1.08, girls: -1.0±1.16; P = 0.09, and there was no difference between the two groups at either time point. We concluded that aromatase inhibitors used in boys and girls in order to increase their predicted adult height, have no apparent effect on their bone health.