How Many Americans Have ALS? The National ALS Registry's 2015 Count

Amyotrophic lateral sclerosis (ALS), often called Lou Gehrig's disease, is a progressive, fatal disease of the nerves that control muscles; most patients die within 2–5 years of diagnosis. Familial (inherited) ALS makes up 5%–10% of cases; the rest have no clear cause. It affects people of every race and ethnicity, but white people, men, non-Hispanic people, people aged 60 and older and those with a family history are more likely to develop it. There is no cure; the drugs edaravone and riluzole slow it in some patients.

How the Registry counts cases

Congress's ALS Registry Act of 2008 created the National ALS Registry, which began collecting data in 2010. ALS isn't a nationally notifiable disease, so the Registry uses two approaches:

1. National databases — Medicare, the Veterans Health Administration and the Veterans Benefits Administration — screened by an algorithm that uses diagnosis codes, neurologist visits and prescriptions. Only "definite ALS" cases are entered. From October 1, 2015, the algorithm switched from ICD-9 to ICD-10 codes, with no apparent effect on case finding.
2. A secure web portal where people with ALS can enroll themselves and fill in up to 17 short surveys on possible risk factors — jobs, military service, smoking, alcohol, family history, head and neck injuries.

Cases stay on the count until confirmed deceased through the National Death Index.

The 2015 count

16,583 people had definite ALS — 62% found through the databases alone, 19% through the portal alone, and 19% through both. 6,250 new cases were found in 2015 and 5,594 registered people died, a net increase of 656. Prevalence was 5.2 per 100,000, close to 5.0 in 2014 (15,927 cases).

The ratio of men to women was 1.6 to 1.

Estimated ALS prevalence by age group, 2012–2015. Figure from CDC's report.

What it means

• The patterns — more common in white people, men and people 60 and older — match 2010–2014.
• The net rise of 656 cases is probably from better case finding in Medicare data as records build up over years, not necessarily more ALS. More years are needed to see trends.
• Regional differences likely reflect population makeup: more white residents in the Midwest and Northeast, more diversity in states such as California.

Research

• The National ALS Biorepository collects samples at home (blood, urine, saliva) and after death (brain, spinal cord, spinal fluid, muscle and more) from a nationally representative set of enrollees — ideally at least one person per state — and pairs them with risk-factor survey answers for researchers.
• Since 2010 the Registry has funded 16 research projects, three new in 2018, on environmental pollutants, epigenetics, cyanobacteria and prior medical conditions.
• Its research notification system connects patients with clinical trials; about 40 institutions have used it.

Limits

• ALS isn't notifiable, so cases may be missed, and the databases lean toward people 50 and older — although Medicare and Veterans Affairs waive waiting periods and age rules for ALS.
• Deduplication across sources may be imperfect.
• Incidence can't be calculated, because 79.6% of cases lack a diagnosis date.

Sources

Based on Mehta P, Kaye W, Raymond J, et al., "Prevalence of Amyotrophic Lateral Sclerosis — United States, 2015," MMWR Morbidity and Mortality Weekly Report, volume 67, Centers for Disease Control and Prevention, Agency for Toxic Substances and Disease Registry; a work of the United States government in the public domain.