Investigate quality of life (QoL) in adults with genetically proven Spinal Muscular Atrophy (SMA) at baseline and after 14 months of Nusinersen therapy.

This is a secondary analysis from an open label single center study on adults with SMA treated with Nusinersen. We assessed health-related quality of life (HR-QoL) at baseline and at 2, 6, 10, and 14 months post-treatment in adults with SMA using the SF-36. The SF-36 physical component summary (PCS) and mental component summary (MCS) scores, standardized to a US reference population, were calculated. Patients were stratified based on their ability to independently ambulate 30 feet. Linear mixed models were used to explore the change of these measures across time with random intercepts for each participant.

Data from 32 participants (18 women; 14 men), mean age 38.35 (range 18-65), and 13 ambulatory (40%) were analyzed. Neither non-ambulatory nor ambulatory patients showed significant changes in the MCS. In the non-ambulatory group, the PCS increased significantly at 2- and 10-month post-treatment compared to baseline with a similar trend at 14-month. In contrast, there were no significant changes in the ambulatory group. 

Non-ambulatory patients' perception of their own physical QoL significantly increased following Nusinersen treatment. Although paradoxical, it has been reported that measured low physical function has been associated with higher quality of life. This could be even more true for more disabled patients in whom small significant changes are still hard to recognize by physicians. Finally, ambulatory and non-ambulatory groups reported an overall stable mental quality of life.