Is firstly diagnosed ALS really ALS? Results of a population-based study with long-term follow-up

Abstract

Objective: To revise the first diagnosis of amyotrophic lateral sclerosis (ALS) in patients from a well-defined population.

Methods: Patients diagnosed with ALS in the years 1998-2002 and resident of Lombardy Region, Northern Italy were followed until death or April 30 2016 to assess long-term survival. During follow-up, the caring neurologists were asked to confirm the first diagnosis. Revised diagnoses were classified as confirmed and unconfirmed motor neuron disease (MND) with further specification where available. The two groups were compared for age, sex, disease duration at diagnosis, site of onset, and El Escorial category. Survival with predictors were also compared.

Results: Included were 280 men and 203 women aged 18-93 years. During follow-up, 25 cases (5.2%) received a diagnosis different from MND. Diseases of spinal roots and peripheral nerves and vascular encephalopathy predominated. Patients with definite (OR 0.15; 95%CI 0.04-0.52) and probable (OR 0.15; 95%CI 0.04-0.62) ALS were least likely to have an unconfirmed MND diagnosis. At end of follow-up, 2.2% of patients with confirmed MND and 44.0% of patients with unconfirmed MND were reported alive (HR 0.14; 95%CI 0.08-0.25).

Conclusions: At the time of a first diagnosis of ALS, the possibility still exists that another, less severe clinical condition, is present.

Key words:

• Amyotrophic lateral sclerosis
• motor neuron disease
• false positive diagnosis
• epidemiology

Disclosure of interest

Drs Poloni and Bianchi report no conflicts of interest.

Dr Pupillo has received funding from the American ALS Association and Italian Ministry of Health for data management and data monitoring of an observational study protocol. She received funding from Italian Drug Agency (AIFA) for data monitoring and study management of randomised clinical trial.

Dr Beghi serves on the editorial boards of Amyotrophic Lateral Sclerosis, Clinical Neurology & Neurosurgery, and Neuroepidemiology; is an associate editor of Epilepsia Open; has received money for board membership from VIROPHARMA and EISAI; has received funding for travel and speaker honoraria from UCB-Pharma, Sanofi-Aventis, GSK; has received funding for educational presentations from GSK and grants from the Italian Drug Agency and from the Italian Ministry of Health.