G.P.98 : Changes in height and age adjusted DXA bone indices with oral bisphosphonate treatment in Duchenne muscular dystrophy

Abstract

Osteoporosis is a major problem in Duchenne Muscular Dystrophy (DMD) due to long term glucocorticoid (GC) therapy and impaired mobility. There are currently no standard of care guidelines for detection or treatment of osteoporosis in DMD. There is limited data on bisphosphonate (BP) treatment of osteoporosis in pediatric DMD patients. This is the first study using height and age adjusted Z scores to assess changes in bone mineral density (BMD) and bone mineral content (BMC) in DMD boys treated with oral BP. To assess changes in bone mineral density (BMD) and bone mineral content (BMC) in DMD boys treated with oral BP. Retrospective study of total body (TB) and lumbar spine (LS) BMD and BMC by DXA in DMD boys treated with oral alendronate, studied between January 2005 and July 2012. Height- and age-adjusted Z-scores (HAZ) were derived. Paired t -tests were used to compare changes in BMD and BMC one year prior and one year post BP treatment. We studied 26 BP-treated DMD boys (mean age ± SD 10.9 ± 3.8 yrs and daily GC duration 3.3 ± 1.5 yrs at BP start). BP treatment duration at the end of the study period was 2.8 ± 1.1 yrs. Prior to starting BP, TB BMD and BMC-HAZ decreased progressively, while LS BMD and BMC-HAZ remained stable. Mean TB BMD and BMC-HAZ were −1.89 and −2.90 and mean LS BMD and BMC-HAZ were −0.89 and −1.07 at BP initiation. DXA bone indices stabilized or improved with BP treatment. There was significant improvement in LS BMD-HAZ ( p p p = 0.0092) after one year of BP treatment. Oral BP treatment stabilized further decline of TB bone indices, and improved LS BMD and BMC HAZ and TB BMC HAZ. Our study suggests that oral BP may be beneficial for bone health in DMD boys. Further study to assess clinical correlation of changes in DXA bone indices is needed to evaluate efficacy of oral BP treatment for osteoporosis in DMD patients.