P.27 Spinal aspects in DMD patients on intermittent corticosteroid dosing - a single center study

Abstract

Scoliosis and low bone mineral density (BMD) are common in Duchenne muscular dystrophy (DMD). Treatment with corticosteroids (CS) delays the onset of scoliosis, but also induce low BMD, resulting in increased fracture risk. We report natural history data in DMD patients treated with CS in a 10 days on/off scheme. Spinal imaging was obtained by yearly anterioposterior radiographs. Scoliosis was defined as a lateral spinal curvature with a Cobb's angle of more than 10 degrees as assessed by a qualified radiologist. Yearly BMD Z-scores were measured with dual-energy X-ray absorptiometry (DXA) scan of the lumbar spine. Vertebral fractures assessment (VFA) was done using physician viewer from Hologic. Vertebral height loss was assessed by a trained technician. Data from 112 patients were reviewed. Thirty-eight were excluded because of missing data (27) or different CS regime (11). From the remaining 74 patients, 499 AP radiographs and 489 DXA scans were included from 2010 to 2021. Sixty-four patients (86.5%) developed scoliosis (median age 10.8 yrs, 95% CI: 9.6-12.2). In this group mean annual increase in Cobb's angle was 7.8 degrees. Scoliosis progressed to 20 degrees in 34 (53.1%) and to 30 degrees in 23 (35.9%) patients. Spinal fusion was done in 18 (median age 15.5 yrs). BMD Z-score declined below -2.0 in 34% of the patients. Z-scores were significantly lower after loss of ambulation (-1.58 vs -0.75, p-value<0.01 using a linear mixed effect model). Of the 74 patients, 61 patients underwent a total of 238 VFA`s, with 17 patients having vertebral height loss at some point during follow-up. There was no correlation between Z-scores and development of scoliosis. Scoliosis is common in DMD patients on intermittent CS treatment, whereas vertebral fractures may be less prominent when compared to daily dosing. Natural history data are important to discuss risk-benefit balances in shared decision processes.