Objective: In order to define the predictors of prolonged survival available at the time of first examination we performed a historical cohort study of amyotrophis sclerosis (ALS) patients referred to our ALS Clinic over the last 20 years.
Methods: In a group of 1034 patients with the diagnosis of definite or probable ALS the effects of individual prognostic factors on tracheostomy-free survival were assessed with the Kaplan-Meier life-table method. The prognostic value of each factor was estimated using univariate and multivariate Cox proportional hazard analyses.
Results: The median survival time was 3.45 years, (95%CI 3.27-3.74). Both the univariate and multivariate Cox models indicated that younger age, limb site of onset, longer diagnostic delay, lower Appel ALS score (AALSS) at first examination, lower AALSS-rate of change between first symptom and first exam (preslope), and higher baseline forced vital capacity (FVC) were associated with longer survival. In addition, four factors: age, diagnostic delay, baseline FVC and AALSS preslope have been identified as independent predictors of survival in our patient population.
Conclusions: The identification of younger age, limb site of onset and longer diagnostic delay as predictors of prolonged survival in ALS clinic population supports the findings of several, earlier studies that were based on smaller groups of patients. More significantly, several additional variables assessed at the first examination predict longer survival: lower baseline AALSS, lower AALSS- preslope and higher baseline FVC. All of these parameters are of value in patient management and in clinical trial development.