Evaluating ALSFRS-R as an indicator of disease milestones and functional independence: An observational study of US neurologists and their patients with amyotrophic lateral sclerosis

BACKGROUND: The Revised Amyotrophic Lateral Sclerosis (ALS) Functional Rating Scale (ALSFRS-R) is a clinician-reported outcome measure monitoring disease progression in people living with ALS (pALS). This study examined the relationship of ALSFRS-R scores with disease progression and independence levels for activities of daily living (ADLs) among pALS. METHODS: Real-world data, including the ALSFRS-R, were drawn from a cross-sectional survey of US neurologists treating pALS (Adelphi ALS Disease Specific Programme™), conducted between July 2020 and March 2021. ALSFRS-R scores were modeled against 11 pre-defined disease milestones. The relationship between ALSFRS-R scores and levels of independence in 24 ADLs was examined using ordered logistic regression. RESULTS: Fifty-nine neurologists provided data for 379 pALS (mean age: 59.5 years; mean disease duration: 16.1 months). Estimated mean ALSFRS-R total score decreased (worsened) from 46.1 at first consultation regarding ALS symptoms to 25.1 upon receipt of a feeding tube. In general, pALS were likely to be completely dependent in most ADLs when their ALSFRS-R total scores were ≤ 25. A 1-point decrease in ALSFRS-R total score was associated with increased risks of losing independence across all ADLs. For each ADL, a 1-point decrease in domain score was associated with varying risks of losing independence across different domains. CONCLUSIONS: There is a correlation between ALSFRS-R scores and levels of independence in ADLs among pALS, facilitating score interpretation for monitoring disease and function status. Yet, the relevance of the ALSFRS-R total score diminishes in advanced stages of ALS, indicating a need for additional measures to provide comprehensive evaluation.