Respiratory management in spinal muscular atrophy: development of a global outcome measure.

Spinal muscular atrophy is a multisystem neuromuscular condition which crosses a spectrum of paediatric care. With disease modifying therapies demonstrating a range of clinical responses, effectively monitoring change is vital. The need for a respiratory longitudinal outcome measure is important due to the large impact on patient quality of life and cost to healthcare. The International Spinal Muscular Atrophy Consortium is developing a global scale for assessing the overall status of patients with SMA. We report the process of creating and piloting the pulmonary module. 10 respiratory specialists, with experience managing patients with SMA, developed a single module to be used across the developmental spectrum. Modules included Clinical History, Physical Exam, and Pulmonary Function Testing. The module was piloted at three institutions, demonstrating the module was easy to use and produced data in 51 subjects representing SMA types 1, 2 and 3. The data demonstrated differences between the three types: patients with SMA1 had the lowest score, and increasing scores for patients with SMA2 and SMA3, respectively. Designing the module to assess the respiratory status in SMA is both feasible and allows for discrimination between SMA subtypes. While results are encouraging, more data is needed to validate the module and determine its precision.