Effects of Demographic Factors on Survival Time after a Diagnosis of Amyotrophic Lateral Sclerosis

Abstract

Background: The Agency for Toxic Substances and Disease Registry established surveillance projects to determine the incidence, prevalence, and demographic characteristics of persons with Amyotrophic Lateral Sclerosis (ALS) in defined geographic areas. There is a need to characterize and account for the survival and prognostic factors among a population-based cohort of ALS cases in the United States. Methods: A cohort of incident cases diagnosed from 2009-2011 in New Jersey was followed until death or December 31, 2013, whichever happened first. Survival was assessed using Kaplan-Meier curves and Cox proportional hazards regression was used to identify prognostic factors. Results: Sixty-four percent of incident cases died between 2009 and 2013, 93.7% specifically from ALS. Among the 456 cases studied in the survival analysis, the median survival from diagnosis was 21 months; 46% of cases survived longer than two years from diagnosis. Older age predicted shorter survival. While there is some indication of differences because of sex, race, and ethnicity, these differences were not statistically significant when accounting for age. Conclusions: New Jersey mortality data were queried to determine the vital status of a cohort of incident ALS cases and used to investigate relationships between demographic factors and survival. Results are consistent with other population-based studies. Older age was a strong predictor of shorter survival time. Additional follow-up time is needed to characterize longer-term survival.