Incidence of Amyotrophic Lateral Sclerosis in Older Adults.

Document Type



INTRODUCTION/AIMS: We investigated age- and sex-specific incidence and survival of Medicare beneficiaries with amyotrophic lateral sclerosis (ALS) aged 66-90 years.

METHODS: We identified all incident ALS cases within a population-based sample of Medicare beneficiaries in 2009 (22,000,177 person-years at risk for ALS). We calculated age- and sex-specific incidence in 2009 according to multiple, progressively more stringent case definitions. Our most inclusive definition required one ALS code, while the most restrictive definition required at least one additional ALS code >6 months after the first code, including one from a neurologist. We identified associated imaging studies and electrodiagnostic testing and followed all cases through the end of 2014 to determine survival.

RESULTS: The overall incidence for our most inclusive definition was 22.84/100,000 person-years for men and 16.05/100,000 person-years for women. The overall incidence was 5.72/100,000 person-years for men and 3.99/100,000 person-years for women for our most restrictive definition. In our most inclusive definition, fewer than 39.7% of cases ever had an ALS diagnosis from a neurologist, more than 50% had an electrodiagnostic test or imaging study, and 40.1% survived less than a year after diagnosis, with 25.5% of these cases surviving ≤6 months. Cases who did not meet the most restrictive definition were more likely than those who did meet the restrictive definition to be older, Black, or Asian.

DISCUSSION: The oldest and marginalized Medicare beneficiaries diagnosed with ALS are less likely to be included in epidemiological studies with restrictive definitions; however, future studies will need to assess the accuracy of diagnosis. This article is protected by copyright. All rights reserved.

Publication Date


Publication Title

Muscle & nerve



PubMed ID


Digital Object Identifier (DOI)


This document is currently not available here.