P.11.10 Height predictions using ulna length are inaccurate in glucocorticoid-treated boys with Duchenne Muscular Dystrophy (DMD)

Height can be difficult to measure accurately in DMD. Height is essential to assess growth, body mass index, nutritional status, body surface area, pulmonary function and bone health, which are fundamental issues in DMD care. Ulna measurement predicts height in healthy children, and has been proposed as a good predictor of height in DMD. Prediction equations have not been validated in DMD boys on glucocorticoid (GC) therapy. To determine if ulna length accurately predicts standing height in GC-treated DMD boys. We hypothesized that ulna-derived height prediction (U-Ht) is valid in DMD. Cross-sectional study of pre-pubertal, ambulatory, GC-treated DMD boys. Standing heights were compared to U-Ht (all measures performed in triplicate and averaged) using the published equation: height (cm) = 4.605U + 1.308A + 28.003 (U = ulna length, cm; A = age, yrs). Equations were also computed using bone ages (BA) interpreted by a single observer. 43 boys, aged 8.7 ± 1.6 yrs (BA 6.9 ± 1.4 yrs), had received GC for 3.0 ± 1.4 yrs. U-Ht was greater than actual height by 3.4 ± 2.9 cm (p