Prognostic Factors and Epidemiology of Amyotrophic Lateral Sclerosis in Southeastern United States

Abstract

Objective: To assess the performance of known survival predictors and evaluate their stratification capability in patients with amyotrophic lateral sclerosis (ALS).

Patients and methods: We analyzed demographic and clinical variables collected at the Mayo Clinic, Florida ALS center during the first clinical visit of 1442 (100%) patients with ALS.

Results: Our cohort had a median (interquartile range [IQR]) age at diagnosis of 64.8 (57-72) years; 1350 (92%) were non-Hispanic White; and 771 (53.5%) were male. The median (IQR) diagnostic delay was 10.1 (6-18) months, body mass index was 25.4 (23-49), and forced vital capacity was 72% (52%-87%). Approximately 12% of patients tested carried a pathologic C9orf72 hexanucleotide repeat expansion. Median (IQR) ALS functional rating scale-revised score was 35 (29-40) and ALS cognitive behavioral screen score was 15 (12-17). The median (IQR) survival after diagnosis was 17.2 (9-31) months, and survival from symptom onset was 30 (20-48) months. We found that older age decreased forced vital capacity, and fast-progressing ALS functional rating scale-revised scores significantly (P<.0001) influence survival curves and associated hazard risk.

Conclusion: Although results obtained from our cohort are consistent with other reports (eg, men with spinal onset experience a longer survival than women with bulbar onset), they remind us of the complexity of the disease's natural history and the limited prognostic power of the most common clinical predictors.

Figure

Kaplan-Meier survival curves. Probability of survival of (A) age at first visit (P<1e-4); (B) site of onset (P<1e-4); (C) forced vital capacity (P<1e-4); (D) Functional rating scale-revised (P=4e-4); (E) diagnostic delay—months (P<1e-4); and (F) progression rate (P<1e-4). ΔFS indicates progression rate.