ESPE Abstracts

Introduction: Bone Health Index (BHI) determined by measurement of cortical thickness of metacarpalia II-IV in x-rays of the left hand represents a method to estimate bone health in children. Aim of this study was to investigate changes of BHI SDS in the course of growth hormone (GH) treatment.

Method: 256 consecutive children with short stature (isolated GH deficiency (IGHD) n = 121, multiple pituitary hormone deficiency (MPHD) n = 49, intrauterine growth retardation (small for gestational age (SGA)) n = 52, SHOX (short stature homeobox gene) deficiency n = 9, Ullrich Turner syndrome (UTS) n = 25) and start of treatment with GH between 2010 – 2018 were included. Repetitive BHI SDS were analysed retrospectively by BoneXpert software in X-rays of the left hand routinely taken for bone age determinations (Greulich & Pyle). Relevant clinical data (anthropometry, IGF1 concentrations) were extracted from the electronic patient charts. Results are presented as median (25%/75% interquartile ranges).

Results: Before the start of GH therapy, the BHI SDS was decreased and similar in all patients regardless their diagnoses(-0.97; -1.8/-0.3); bone age according to Greulich and Pyle was retarded (-1.6 years; -2.31/-0.97) compared to chronological age; height velocity SDS (-1.68; -2.52/-1.01) as well as serum IGF1 (SDS -1.90; -2.68/-1.20) were decreased; BHI SDS were not correlated with retarded bone ages (r=0.02; P=0.753) or height SDS (r =-0.088; P=0.171). BHI SDS increased to -0.17 (-1/0.58) after 1.5 years (0.5-1.49; P=<0,01) of GH treatment. Thereafter BHI SDS (-0.2; -1.00/0.50) remained unchanged and similar in all patients throughout the study period (5.3 years; 3.45/7.25). BHI SDS correlated with height velocity SDS and serum IGF-I SDS in the course of GH treatment. Retardation of bone age did not change significantly after 1.5 years (-1.64; -2.40/-1.05; P=0,49) but improved after (-0.66 (-1.52/0.14; P=<0,01 at the end of study). Catch-up growth was most pronounced in the first year of treatment (height velocity SDS 2.12 vs. SDS 0.31 at the end of study). Serum IGF 1 levels normalized within 1.5 years (SDS 0.10; -0.70/0.70) and remained unchanged thereafter (SDS 0.2; -1.00/0.90).

Conclusion: BHI SDS are reduced in GH naive children with short stature regardless of the etiology, increase initially after GH start with plateauing thereafter indicating sustained bone health and correlate with height velocities and serum IGF-I during GH treatment. Thus, bone health as estimated by BHI represents a relevant target of GH therapy in children.