Trajectories of impairment in amyotrophic lateral sclerosis: Insights from the Pooled Resource Open-Access ALS Clinical Trials cohort.
Rate of decline of the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) score is a common outcome measure and a powerful predictor of mortality in ALS.METHODS
Observed rate of decline (postslope) of ALSFRS-R, its linearity, and its relationship to decline at first visit (preslope) were examined in the Pooled Resource Open-Access ALS Clinical Trials cohort by using longitudinal mixed effects models.RESULTS
Mean ALSFRS-R postslope in 3,367 patients was -0.99 points/month. Preslope and postslope were correlated and had powerful effects on survival. ALSFRS-R trajectories were slightly accelerated overall, but slope and direction/degree of curvature varied. Subscore decline was sequential by site of onset. Respiratory subscore decline was the least steep.DISCUSSION
Variable curvilinearity of ALSFRS-R trajectories confounds interpretation in clinical studies that assume linear decline. Subscore trajectories recapitulate phenotypic diversity and topographical progression of ALS. ALSFRS-R is better used as a multidimensional measure. Muscle Nerve, 2017.