Assessing the Relationship of Quality of Life With Functional Status in a Large Cohort of Adult Patients With Neuromuscular Disorders.

Background and Objectives: Health-related quality of life (HR-QoL) is compromised in patients with neuromuscular disorders (NMDs). Disease severity alone does not predict HR-QoL; there are other known predictors including physical, psychological, and social factors. This study aims to provide insight into how mobility, age, and diagnosis may affect HR-QoL in adults with NMD. Methods: The QoL in Genetic Neuromuscular Disease Questionnaire (QoL-gNMD) was completed by adult patients with NMDs before attending a clinical visit at the John Walton Muscular Dystrophy Research Centre in Newcastle upon Tyne, UK. The Summary of Function Scale was administered during the clinical visit to characterize mobility status. Results: A total of 580 responses were included in this cross-sectional study. Overall perceived health and HR-QoL were reported poorest by ambulant patients who walked using aids. Items from the QoL-gNMD that were affected the most by NMDs were future planning and the need to rely more on others. A nonlinear trend where patients with "midlevel" mobility (walked with aids or manual wheelchair users) reported the poorest HR-QoL were observed in all 3 HR-QoL domains: Impact of Physical Symptoms (IPSs), Self-Perception (SP), and Activities and Social Participation (ASP). This nonlinear trend between HR-QoL and mobility was observed for younger patients but became more linear in older age groups. In our cohort, patients with "midlevel" mobility were the oldest, and those with the lowest levels of mobility (i.e., powered wheelchair users) were the youngest. Interaction between age and mobility was significant and both affected HR-QoL. There was marked variability in HR-QoL between diagnoses. Diagnosis was a significant factor for IPS ( Discussion: Age and mobility status affect HR-QoL. Individuals with limited ambulation reported the poorest HR-QoL, which was partially restored in powered wheelchair users, to levels comparable with more ambulant patients. However, the positive effect of wheelchair use became less substantial as patients get older. There was also marked variability in HR-QoL between diagnoses that was unrelated to physical disability. These findings provide evidence to guide care management discussions and highlight the importance of timely introduction of powered mobility.