Background: Published studies of radiologically confirmed fractures in sufficiently large cohorts of boys with Duchenne Muscular Dystrophy (DMD) are limited.
Objective: To determine the incidence of fractures in a contemporary cohort of 91 boys with DMD managed in all Scottish centres.
Method: Radiologically confirmed fractures were classified into vertebral fracture (VF) and non-VF in a retrospective audit of all boys currently managed in Scotland. Probability of fractures was determined by KaplanMeier plot.
Results: At last assessment at a median age of 11.2 years (range, 2.318.9), 45/91 (50%) were non-ambulant. Of 91, 51 (56%) were on Glucocorticoid (GC) at last assessment, 11/91 (21%) were GC naïve, 23/91 (25%) were previously treated with GC and in 6 (7%), this information was unavailable. By last assessment, 43 boys (47%) had sustained fractures. On KaplanMeier analysis, 50% of the cohort had sustained a fracture by the age of 10.2 years and 75% had sustained a fracture by 12.8 years. Non-VF occurred in 36/91 (40%). Seven (8%) of those boys who sustained non-VF were GC-naïve, median age of 3.5 years (2.0,10.1). Symptomatic VFs were reported in 8/91 (9%). In those who were started on GC, there was a period of 2.3 years before the first symptomatic VF was diagnosed and 50% had sustained VF by 8 years after start of GC (95% CI: 6.39.6). Multivariate analysis including boys currently and previously treated with GC showed that no single clinical factor (age at starting GC, duration GC, age lost ambulation) was associated with fractures.
Conclusion: In this study of a contemporary nationwide cohort of boys with DMD, it is clear that radiologically-confirmed non-VFs can occur irrespective of GC therapy, whereas there is a latency period of 2 years before detection of the first symptomatic VF. The data gleaned from this large cohort will inform the design of future interventional studies of bone protective therapy powered on fracture reduction.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology