Prognostic Factors in Amyotrophic Lateral Sclerosis: A Population-Based Study

OBJECTIVE To determine the prognostic factors associated with survival in amyotrophic lateral sclerosis at diagnosis. METHODS This retrospective population-based study evaluated 218 patients treated with riluzole between 2005 and 2014 and described their clinical and demographic profiles after the analysis of clinical data and records from the mortality information system in the Federal District, Brazil. Cox multivariate regression analysis was conducted for the parameters found. RESULTS The study sample consisted of 132 men and 86 women with a mean age at disease onset of 57.2±12.3 years; 77.6% of them were Caucasian. The mean periods between disease onset and diagnosis were 22.7 months among men and 23.5 months among women, and the mean survival periods were 45.7±47.0 months among men and 39.3±29.8 months among women. In addition, 80.3% patients presented non-bulbar-onset amyotrophic lateral sclerosis, and 19.7% presented bulbar-onset. Cox regression analysis indicated worse prognosis for body mass index (BMI) <25 kg/m2 (relative risk [RR]: 3.56, 95% confidence interval [CI]: 1.44-8.86), age >75 years (RR: 12.47, 95% CI: 3.51-44.26), and bulbar-onset (RR: 4.56, 95% CI: 2.06-10.12). Electromyography did not confirm the diagnosis in 55.6% of the suspected cases and in 27.9% of the bulbar-onset cases. CONCLUSIONS The factors associated with lower survival in amyotrophic lateral sclerosis were age >75 years, BMI <25 kg/m2, and bulbar-onset.