Researchers Determine What Patients, Caregivers Deem Meaningful Change in SMA Motor Function

Findings from a 3-part study are giving insight into how patients with spinal muscular atrophy (SMA) and their caregivers perceive changes, or lack thereof, in motor function. Through the use of patient testimonials as well as analysis of data from a study of SMA patients, researchers were able to describe patient-centered “meaningful outcomes” in the 32-item Motor Function Measure (MFM32).

MFM32, a clinician-reported measure of both fine and gross motor ability, is among the various clinical outcomes assessments created to quantify signs and symptoms of motor function among patients with SMA and other neuromuscular disorders. Abilities measured by the tool include walking and standing up from sitting, rolling and sitting, and finger dexterity and hand function.

However, the researchers of the study note that although research has confirmed the reliability, validity, and responsiveness of MFM32, there is still an inadequate understanding of meaningful change in ability from a patient-centered perspective.

Using a multipronged approach that leveraged both qualitative and quantitative methodologies, the researchers performed semistructured interviews and disseminated an online survey to describe clinical meaningfulness of changes in a patient-friendly version of MFM32. The group also conducted an independent quantitative analysis of data from the SUNFISH Part 2 randomized controlled trial to describe meaningful change using the validated version of the tool.

“The combined qualitative and quantitative approaches represent endorsed methods, ensuring inclusion of the patient voice via the collection of interview and survey data using patient-friendly versions of the MFM32 as well as traditional quantitative methods using the validated MFM32 clinical assessment,” stated the researchers in their paper.

Findings from the 40 interviews and more than 200 answered surveys from patients with SMA types 2 and 3 and caregivers validated that a change or maintaining functional ability over 1 year, as determined by MFM32, is an important outcome. Every interviewee indicated that improvement in functional ability is a meaningful outcome, and 98% of interviewees said that both deterioration of and maintaining functional ability are meaningful outcomes.

The online surveys showed similar findings, with 90% of respondents answering that maintaining functional ability over 1 year based on the patient-friendly version of the measure was meaningful, citing feelings of being able to maintain quality of life, having reassurance that their disease was not progression, and being able to maintain independence.

“The individuals with SMA and caregivers enrolled in the qualitative interview and survey sample confirmed that stability on the concepts assessed in the patient-friendly MFM32 over 1 year is a meaningful outcome across SMA types and functional status (ie, ambulant and non-ambulant individuals),” wrote the researchers. “This finding supports the importance of examining ≥0 points change on MFM32 as a meaningful change threshold. This is in line with previous interview and survey findings that have included children, adolescents and adults with SMA and have similarly found that maintaining current ability is a meaningful outcome.”

In the final leg of their analysis, the researchers compiled data from 180 patients in Part 2 of the SUNFISH trial, determining that at the patient level, approximately 3 points is a meaningful improvement in motor function using the validated version of MFM32.

Reference

Duong T, Staunton H, Braid J, et al. A patient-centered evaluation of meaningful change on the 32-item motor function measure in spinal muscular atrophy using qualitative and quantitative data. Front Neurol. Published online January 17, 2022. doi:10.3389/fneur.2021.770423