2024 American Academy of Neurology Abstract Website

Channa Hewamadduma¹, Laura Chapman², Sophie McNicholas², Oliver Cousins³, Luke Borg⁴, Anshul Navalgaria², Lindsay Maidment², Zahra Cader², Rosa Tanzi³, Anna Rutherford⁴, Sherryl Chatfield³, Phillip Kelly⁴, Jon Street², Katie Nevin², Clare Galtery³, James Lilleker⁴
¹Neuromuscular Unit, Sheffield Institute for Translational Neurosciences, University of Sheffield, Sheffield, UK, ²Academic Neurosciences, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, UK, ³Atkinson Morley Neurosciences Centre, St George's University Hospitals NHS Foundation Trust, London, UK, ⁴Muscle Disease Unit, Salford Royal Hospital Northern Care Alliance NHS Foundation Trust, Manchester, UK

Objective:

To describe the impact of poor-bone health as an under-recognised comorbidity in the adult SMA patients.

Background:

Spinal muscular atrophy (SMA) due to loss of SMN1 causes progressive, symmetrical muscle weakness. Patients with SMA are at a higher risk of reduced bone mineral regardless of age or type of SMA. Ambulant SMA type 3 patients are at risk of fractures due to falling, and may struggle to recover ambulation post-fracture, whilst SMA type 2 patients are at risk of fractures during transfers, and equipment use causing significant pain and further reduced limb function. Bone health monitoring and fracture prevention is thus of critical importance in the management of SMA.

Design/Methods:

An audit tool was designed by a multi-disciplinary team. We assessed the bone health in a large multi-centre cohort of adult-SMA patients from the UK. We collected demographics, phenotype, genotype, bone biochemistry, functional outcome measures, DEXA scan results, fracture risks, rate of falls and fractures, and any preventative interventions.

Results:

Total of 136 patients (median age of 29.5 years) were included (SMA Type 2 and 3 were, n=61 and 71 respectively) and 33 were ambulant. 127 patients were treated with either Nusinersen or Risdiplam. DEXA scan was done only in 31% of patients (SMA-Type 2 vs 3, 8% vs 54%, p<0.0006). Suboptimal vitamin D level was observed in 85%, whilst severely low in 60%. 24% (8/33) Type 3 ambulatory SMA patients suffered a low impact fracture in the last two years resulting in loss of ambulation. Follow up DEXA scan results and the impact of therapies on bone outcomes will be discussed.

Conclusions:

Our study highlights that poor-bone health is an under-recognised comorbidity in the adult-SMA patients and future care standards should address this unmet-need. Fracture prevention is particularly important in SMA type 3 patients which is a preventable cause of loss of ambulation.