Analysis of survival and prognostic factors in amyotrophic lateral sclerosis: a population based study

Abstract

Objective To measure survivorship and predictors of prognosis of amyotrophic lateral sclerosis (ALS). Methods Incident cases, diagnosed in the 1998-1999 period and classified according to the El Escorial criteria, were enrolled from a prospective population based registry established in Puglia, Southern Italy, with a reference population of 4,025,329. Cases were followed up until death or 30 June 2004. Results We identified 130 incident cases of ALS while four were lost to follow-up. Median survival was 28 months from first symptoms and 16 months from diagnosis, while cumulative survivorship at 4 years was approximately 30%. Advanced age (>75 years: hazard ratio (HR) 7.5; 95% CI 1.9 to 29.6; p = 0.004) and bulbar or generalised (HR 1.8; 95% CI 1.1 to 3.0; p = 0.01) onset of symptoms were independent predictors of adverse survival. After stratifying patients according to site of first symptoms, age was a predictor of death among spinal (HR for patients aged >75 years compared with patients aged 45 years or less: HR 11; 95% CI 1.5 to 78.5; p = 0.01) but not among bulbar ALS (HR 4.5; 95% CI 0.4 to 46.5; p = 0.2). Among spinal onset cases, cases with predominant upper motoneuronal (UMN) involvement presented with a borderline significant better survivorship (HR 0.5; 95% CI 0.2 to 1.3; p = 0.1) Conclusions Bulbar signs and advanced age among subjects with spinal onset were indicators of poor prognosis while El Escorial category at entry did not predict survival. Among subjects wit…