Exploring the diagnosis delay and ALS functional impairment at diagnosis as relevant criteria for clinical trial enrolment.

ABSTRACT

Objectives were i) to describe the phenotypic heterogeneity of incident amyotrophic lateral sclerosis (ALS) patients diagnosed in 2012 in French ALS centres; ii) to look at the associations between ALSFRS-R score and ALSFRS-R slope (ΔFS) at time of diagnosis with diagnosis delay, ALS phenotypes and Airlie House diagnosis criteria (AHDC); iii) to describe the rate of progression on ΔFS, according to diagnosis delay. METHODS: Incident ALS cases diagnosed in French ALS centres were included. The rate of progression was evaluated as follows ΔFS = (48 - ALSFRS-R at time of diagnosis)/duration from onset to diagnosis (months). Fast and slow progressors were defined by ΔFS >1 and <0.5, respectively. RESULTS: At time of diagnosis, 476 patients were classified into eight phenotypes bulbar (33.0%), spinal lumbar (28.2%), spinal cervical (23.1%), flail leg (4.4%), ALS/FTD (4.2%), possible flail arm (4.0%), respiratory (2.1%), dropped-head (1.0%). Median ΔFS (n = 358/476) was 1.0 [0.5-2.0]. ΔFS was associated with AHDC (p = 0.009), but not with clinical phenotype (p = 0.902). Stratification on diagnosis delay (<12 months or ≥18 months) allowed to differentiate fast progressors from slow progressors. CONCLUSION: At time of inclusion in therapeutic trial closed to diagnosis, ΔFS or diagnosis delay may discriminate the rate of progression.