Bone Abstracts

Background: There is still limited information on changes in growth especially segmental growth and bone mass of glucocorticoid(GC) treated boys with Duchenne Muscular Dystrophy (DMD).

Objectives: To evaluate changes in growth and bone mass in GC treated boys with DMD.

Methods: Retrospective study of 15 boys with DMD treated with GC, median age 7.6 years (4.1, 15.5) who had repeated DXA scan for clinical monitoring of bone health, median follow-up 1.6 years (1.0, 4.7). Height (Ht), sitting height (SH) and leg length (LL) were obtained from DXA images. Total body less health bone mineral content (TBLH-BMC) and lumbar spine bone mineral apparent density (LS-BMAD) were converted into SDS based on recent published information in 3598 UK children and adolescents (1). Results reported as median (range).

Results: At baseline, median duration of GC therapy was 3.0 years (0.04,9.8). Nine out of 15 (60%) were on daily Deflazacort, 3/15 (20%) daily Prednisolone, 1/15 (6.7%) pulsed Deflazacort and 2/15 (13.3%) pulsed Prednisolone. GC regimen did not change during the follow-up period. At baseline, 13/15 (86.7%) were ambulant whereas this was 7/15(46.7%) at follow-up. At baseline, median Ht-SDS was −1.4 (−0.4, −4.5) and was significantly lower at follow-up: −3.6 (−1.1, −7.2) (P=0.001). At baseline, median SH-SDS and LL-SDS were −1.4 (−0.2, −4.0) and −2.3 (0.3, −4.8) and both were significantly lower at follow-up respectively: −2.6 (−1.4, −6.1) and −3.8 (0.2, −5.8) (P=0.001). Despite profound growth failure, median TBLH-BMC SDS at baseline and follow-up were not different: −3.5 (−7.4, 0.2) and −2.4 (−6.5, 0.4) (P=0.18). Similarly, median LS-BMAD SDS at baseline and follow-up were not different: −1.3 (−2.9, 1.9) and −1.4 (−2.8, 1.8) (P=0.68).

Conclusion: GC treated boys with DMD show profound growth failure with follow-up but this was not reflected in changes in DXA measured bone mass. Novel methods of assessment of bone strength and microenvironment require further exploration in these boys.

Disclosure: The authors declared no competing interests.

Reference

1. Crabtree NJ et al J Bone Miner Res 2017 Jan [Epub ahead of print].