FIRST DATA ON ALS PREVALENCE

The first national prevalence data on amyotrophic lateral sclerosis (ALS) was reported today from the National ALS Registry, using administrative data to ascertain cases of ALS in the United States.

In 2009, the federal Agency for Toxic Substances and Disease Registry (ATSDR), a sister agency to the Centers for Disease Control and Prevention (CDC), implemented the National ALS Registry to collect and analyze data regarding persons with ALS, which is a non-notifiable disease in the United States (except in Massachusetts). The main goals of the Registry, as defined by the 2008 ALS Registry Act, are to describe the incidence and prevalence of ALS better, examine risk factors such as environmental and occupational exposures, and characterize the demographic characteristics of those living with ALS.

In their first report, researchers estimate the overall prevalence of ALS is 3.9 per 100,000 people in the United States, with the highest prevalence (17.0 per 100,000) among those aged 70 to 79 years. Men have a higher prevalence than women (4.8 vs 3.0 per 100,000), and whites a higher rate than blacks (4.2 vs 2.0 per 100,000).

The new report is published online July 24 and appears in the July 25 issue of Morbidity and Mortality Weekly Report (MMWR).

Facilitating Research

ALS is a progressive and fatal neuromuscular disease. Most people with the condition die within 5 years of receiving the diagnosis. There's no known cause, but a hereditary form of the disease, familial ALS, occurs in 5% to 10% of cases.

There is no blood or other test for ALS; diagnosis is based on signs and symptoms and on neurophysiologic tests. There's also no cure, although riluzole (Rilutek, Sanofi-Aventis) has been shown to slow disease progression and has been approved in the United States to treat the condition.

The ATSDR is collecting data from 4 national databases, maintained by Medicare, Medicaid, the Veterans Health Administration, and the Veterans Benefits Administration. Researchers used an algorithm with variables such as international classification codes, a prescription for riluzole, and frequency of visits to a neurologist, to identify people with "definite ALS."

The algorithm, developed during previous pilot projects, was shown to have a sensitivity of 87% and specificity of 85%.

Researchers also used a secure Web portal to identify ALS cases. On this site, patients answer a series of validated screening questions that are very accurate, according to the report authors, led by Paul Mehta, MD, Division of Toxicology and Human Health Science, ATSDR, Atlanta, Georgia. Just over 93% of those who passed the screening questions were determined by a neurologist to have ALS/motor neuron disease.

A total of 12,187 people were identified as having "definitive ALS" across the 4 databases and through the Web portal.

The higher prevalence of ALS among men was observed across all age groups and data sources. The ratio of males to females (1:56) is consistent with other published data, said the authors.