ESPE Abstracts

Background: There is little information on growth and fractures in boys with Duchenne Muscular Dystrophy (DMD).

Objective & hypotheses: To determine the extent of growth & skeletal morbidity in a contemporary cohort of DMD in the UK.

Method: Clinical details of 832 boys with DMD in the North Star database (2006–2015) from 23 centres were analysed following categorisation into five age groups: A:<5 years (n, 113), B:5–7.9 years (384), C:8–10.9 years (421), D:11–13.9 years (299) and E:>14 years (160).

Results: Proportion of boys on glucocorticoids (GC) ranged from 36% in GrpA to 88% in GrpC. Proportion of non-ambulant boys was 26% in GrpD to 56% in GrpE. Of the 46 GC-naïve boys in GrpA, 10/46 (22%) had height standard deviation score (HtSDS)<−2.0. Median HtSDS in GrpE was −1.8 (−4.9,1.0) with 48% <−2.0SD. The difference between the HtSDS of boys on GC and not on GC was only significant in Grp B, D and E (P<0.05). The number of boys with new reports of all fractures in the five groups were 7(6%), 23(7%), 51(12%), 52(17%), 31(19%), respectively. New symptomatic vertebral fractures (VF) were reported in Grps B-E: 2/384 (0.5%), 7/421 (1.7%), 6/299 (2.0%) and 8/160 (5%), respectively. Compared to VF, back pain was more commonly reported in GrpB-E: 16/384 (4%), 46/421 (11%), 42/299 (14%) and 29/160 (18%), respectively. Although there were no symptomatic VF in GrpA, asymptomatic VFs were reported in two boys, aged 4.0 and 4.9 years, who were treated with GC for only 0.5 and 1.0 year, respectively.

Conclusion: In the largest cohort of boys with DMD to date with height and fracture data, short stature was already evident in 22%of young GC-naïve boys and its pathophysiology needs further investigation. VF are present across the age spectrum and the relationship between back pain and VF in this age group requires further exploration.