The impact of nusinersen on respiratory function in adult patients with spinal muscular atrophy after 1.5 years of treatment.

<bold>Background:</bold> Spinal muscular atrophy (SMA) is a severe neuromuscular disorder. The development of nusinersen for SMA patients has led to a need for treatment monitoring. <bold>Objective:</bold> To determine changes in respiratory function in adult SMA patients after 1.5 years of treatment with nusinersen. <bold>Methods:</bold> A total of 33 patients (age 19 – 69 years) with SMA types 2 - 4, who were treated with nusinersen participated in this study. To determine the changes in respiratory function, we performed spirometry tests and respiratory muscle tests: vital capacity (VC), forced expiratory volume in first second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF), maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP) and sniff nasal inspiratory pressure (SNIP). Assessments were conducted before treatment initiation and every six months for 1.5 years. <bold>Results:</bold> Nusinersen treatment over 1.5 years significantly improved respiratory function, with mean increases of 12.74 cmH2O in MEP (t(32) = -3.18, p = 0.003) and 11.82 cmH2O in SNIP (t(32) = -4.14, p < 0.001). PEF showed a non-significant but promising trend towards improvement (t(32) = 1.87, p = 0.071). <bold>Conclusion:</bold> Nusinersen treatment for 1.5 years in adult SMA patients led to significant improvements in key respiratory measures, including MEP and SNIP. While PEF did not reach statistical significance, its observed trend warrants further study due to its potential clinical relevance. Given the progressive nature of SMA, these findings hold promising implications for managing respiratory function in adult patients.