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The Spinal Muscular Atrophy Health Index: A novel outcome for measuring how a patient feels and functions
Author(s) -
Zizzi Christine E.,
Luebbe Elizabeth,
Mongiovi Phillip,
Hunter Michael,
Dilek Nuran,
Garland Connie,
Ciafaloni Emma,
Zaidman Craig M.,
Kissel John T.,
McDermott Michael P.,
Johnson Nicholas,
Sansone Valeria,
Heatwole Chad R.
Publication year - 2021
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.27223
Subject(s) - sma* , spinal muscular atrophy , cronbach's alpha , intraclass correlation , medicine , physical therapy , physical medicine and rehabilitation , patient reported outcome , psychology , disease , gerontology , quality of life (healthcare) , clinical psychology , psychometrics , mathematics , nursing , combinatorics
The Spinal Muscular Atrophy Health Index (SMA‐HI) is a multifaceted, disease‐specific, patient‐reported outcome to measure an SMA patient's perception of their disease burden. In preparation for upcoming therapeutic trials, we examine the validity, reliability, and usability of the SMA‐HI in adults, teenagers, and children with SMA. Methods Using data from a cross‐sectional study of 359 international adult patients with SMA, we identified the most relevant symptoms to include in the SMA‐HI. We utilized factor analysis, patient interviews with adults and minors (age 8‐15 years), known‐group validity testing, and test‐retest reliability assessments to evaluate and refine the SMA‐HI. Results The SMA‐HI measures overall disease burden and 15 areas of SMA health. Fifteen adult patients and five patients, age 8 to 15 years, participated in semistructured qualitative interviews and found the SMA‐HI to be comprehensive, easily completed, and to have clear meaning. The final SMA‐HI and its subscales demonstrated good internal consistency (Cronbach α = 0.77‐0.96), high test‐retest reliability (intraclass correlation coefficient = 0.60‐0.96), and an ability to differentiate between SMA groups with different disease severities affecting areas such as employment and ambulation ( P < .0001 for both). Discussion This research provides evidence that the SMA‐HI is a valid, relevant, and reliable outcome measure to assess multifaceted patient‐reported disease burden in older children, teenagers, and adults with SMA. The SMA‐HI provides an opportunity for researchers and clinicians to measure a SMA patient's perception of their health and determine relevant changes in response to therapeutic intervention or disease progression.