Bulbar-onset amyotrophic lateral sclerosis (ALS) is the most common form of the disease among patients 80 and older at disease onset, a factor that seems to contribute to shorter survival for these patients compared with younger ALS patients, a retrospective study has found.
The study, “Very late-onset amyotrophic lateral sclerosis in a Portuguese cohort,” was published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration.
ALS is a progressive neurological disorder in which motor neurons — the nerve cells responsible for controlling voluntary muscles — gradually degenerate and die, causing muscles to shrink, or atrophy, and become weaker.
According to two European epidemiological studies, in recent years, the steady increase in life expectancy and population aging in Western countries may be contributing to an increased number of much older ALS patients — a group often excluded from clinical trials and poorly characterized in terms of disease presentation, progression, and prognosis.
In this study, researchers focused on examining and characterizing a population of ALS patients who were 80 or older at disease onset, in particular their survival, compared with younger ALS patients.
The retrospective study involved 1,083 ALS patients followed from January 1995 to December 2017. Patients were divided into two groups, depending on their age at disease onset: those younger than 80 and those 80 or older. All parameters analyzed in the study, including demographic, clinical, and survival data, were compared between the two groups.
Only 4.62% of ALS patients were 80 or older at disease onset. More than half (56%) of these patients were men. Regardless of gender, bulbar-onset ALS was the most prevalent form of the disease among older patients, occurring in 54%.
Unlike limb-onset ALS, the most common form of the disease where patients start to experience muscle weakness in the limbs, bulbar-onset ALS affects the muscles of the head and neck, leading to difficulties in speaking and swallowing.
Older ALS patients sought medical assistance much sooner after experiencing their first symptoms than younger patients (13.4 vs. 18.8 months). However, the survival of older ALS patients was shorter than the younger patients (31.9 vs. 45.6 months).
“Shorter total survival in [older ALS patients] was shown to be dependent on predominant bulbar presentation and not related with other factors such as deficient health care practices. Nevertheless, we could not rule-out age-related comorbidities and age-related shorter life expectancy,” the researchers wrote.
No significant differences were found between the two groups of ALS patients regarding cognitive impairments, familial history of frontotemporal dementia associated with ALS (FTD-ALS), non-invasive ventilation, and Rilutek (riluzole) prescription.
These findings suggest that the majority of elderly patients with late disease onset have the ALS bulbar type, which could be one of the reasons why these patients live for shorter periods of time and have, in general, a worse prognosis than younger patients.
“Very-old patients represented a minor but distinctive ALS group. A predominant bulbar presentation (with no gender predilection) was disclosed, and it could probably explain the shorter disease duration and poor prognosis,” the researchers said.