What is amyotrophic lateral sclerosis prevalence?

Abstract

Objective: To assess amyotrophic lateral sclerosis (ALS) prevalence and to analyze how this estimate vary according to the historical depth of data collection. Methods: Data from the PARALS register have been used. Crude prevalence ratio was estimated on 31 December 2015 for the period 2015–2013 and then repeated extending the time interval by 3 years each time. For each time interval, prevalence ratio was calculated globally and stratified by sex, age at diagnosis, and phenotype. Prevalence was also calculated considering patients who underwent tracheostomy during the same study period. Results: Prevalence ratios increased proportionally to the length of the time period considered, ranging from 6 (95% CI 5.3–6.7) for a 3-year period to 12.1 (95% CI 11.1–13.1) per 100,000 population for a 21-year period. Prevalence ratio increase was inversely proportional to age at diagnosis, being null in the >85 years class and maximal in the 25–35 age class (+1700%). Among phenotypes, predominant UMN showed the highest increase (from 0.5, 95% CI 0.3–0.8, to 2.1, 95% CI 1.7 − 2.6, +320%). Discussion: Because of the variability of ALS survival, prevalence ratio strongly depends on the length of the follow-up period. A 12-year period should be sufficient to get a reliable estimate of ALS prevalence including long-survival patients.

Keywords:

• Amyotrophic lateral sclerosis
• epidemiology
• cohort studies
• prevalence
• burden

Acknowledgements

The authors acknowledge the PARALS group: Adriano Chiò, Andrea Calvo, Cristina Moglia, Antonio Canosa, Umberto Manera, Rosario Vasta, Francesca Palumbo, Alessandro Bombaci, Maurizio Grassano, Maura Brunetti, Federico Casale, Giuseppe Fuda, Paolina Salomone, Barbara Iazzolino, Laura Peotta, Paolo Cugnasco, Giovanni De Marco, Maria Claudia Torrieri, Salvatore Gallone, Marco Barberis, Luca Sbaiz, Salvatore Gentile, Alessandro Mauro, Letizia Mazzini, Fabiola De Marchi, Lucia Corrado, Sandra D'Alfonso, Antonio Bertolotto, Maurizio Gionco, Daniela Leotta, Enrico Oddenino, Daniele Imperiale, Roberto Cavallo, Pietro Pignatta, Marco De Mattei, Claudio Geda, Diego Maria Papurello, Salvatore Amaru', Graziano Gusmaroli, Cristoforo Comi, Carmelo Labate, Fabio Poglio, Luigi Ruiz, Delfina Ferrandi, Lucia Testa, Eugenia Rota, Marco Aguggia, Nicoletta Di Vito, Piero Meineri, Paolo Ghiglione, Nicola Launaro, Michele Dotta, Alessia Di Sapio, Guido Giardini, Patrizia Julita, Claudio Solaro.

Declaration of interest

Rosario Vasta, Antonio Canosa, Umberto Manera, Maurizio Grassano, Francesca Palumbo, Paolo Cugnasco, Fabiola De Marchi, Letizia Mazzini: no disclosures. Andrea Calvo has received research support from the Italian Ministry of Health (Ricerca Finalizzata). Cristina Moglia has received research support from the Italian Ministry of Health (Ricerca Finalizzata). Adriano Chiò serves on the editorial advisory board of Amyotrophic Lateral Sclerosis and Neurological Sciences and has received research support from the Italian Ministry of Health (Ricerca Finalizzata), Regione Piemonte (Ricerca Finalizzata), University of Turin and the European Commission (Health Seventh Framework Programme) and serves on scientific advisory boards for Mitsubishi Tanabe, Roche, Denai, and Cytokinetics.

Additional information

Funding

This work was in part supported by the Italian Ministry of Health (Ministero della Salute, Ricerca Sanitaria Finalizzata, Grant RF-2016-02362405), the European Commission’s Health Seventh Framework Programme (FP7/2007-2013 under Grant agreement 259867), the Italian Ministry of Education, University and Research (Progetti di Ricerca di Rilevante Interesse Nazionale, PRIN, Grant 2017SNW5MB), the Joint Programme – Neurodegenerative Disease Research (ALS-Care, Strength and Brain-Mend projects), granted by the Italian Ministry of Education, University and Research. This study was performed under the Department of Excellence grant of the Italian Ministry of Education, University and Research to the “Rita Levi Montalcini” Department of Neuroscience, University of Torino, Italy. This study was partly funded by the AGING Project for Department of Excellence at the Department of Translational Medicine (DIMET), Università del Piemonte Orientale, Novara, Italy.