Long-term survival in amyotrophic lateral sclerosis: a population-based study

Abstract

Objective: To determine the long-term survival in amyotrophic lateral sclerosis (ALS) and identify predictors of prolonged survival in a population-based cohort of newly diagnosed patients.

Methods: An incident cohort from a population-based registry during the years 1998 through 2002 in Lombardy, Italy was followed until death or to February 28, 2013. Age, sex, date of onset of symptoms, site of onset, date of diagnosis, and El Escorial diagnostic category were collected. Survival was assessed using Kaplan-Meier curves. Cox proportional hazards function was used to identify independent prognostic predictors. Standardized mortality ratios (SMRs) were used to assess the 5-year and 10-year excess mortality of ALS patients.

Results: Included were 280 men and 203 women aged 18 to 93 years. Spinal onset ALS was present in 312 cases (64.6%). Definite ALS was diagnosed in 213 cases (44.1%), probable ALS in 130 (26.9%), possible ALS in 93 (19.3%), and suspected ALS in 47 (9.7%). The cumulative time-dependent survival at 1, 5, and 10 years from diagnosis was 76.2%, 23.4%, and 11.8%, respectively. Independent predictors included younger age, the diagnosis of possible/suspected ALS, spinal onset, and symptoms having started >12 months previously at diagnosis. SMR was 9.4 at 5 years and 5.4 at 10 years. SMR at 10 years was higher until age 75 year, predominating in women, and became nonsignificant for males thereafter.

Interpretation: The outcome in ALS varies with phenotype. Longer survival is predicted by younger age, spinal onset, male gender, and suspected ALS. After age 75 years, 10-year survival in men with ALS is similar to the general population.