Associations between co-medications and survival in ALS-a cohort study from Austria.

The aim of this study was to evaluate associations between co-medications and survival of patients with amyotrophic lateral sclerosis (ALS). Prescription databases of the Austrian sickness funds covering more than 5 million people formed the basis of this study. ALS cases were deduced from riluzole prescriptions during the study period from January 1, 2008, to June 30, 2012. After adjusting for potential confounding factors associations between co-medications and ALS survival were analyzed. A total of 522 ALS patients could be identified during the study period. Sixteen of the most frequently used drug classes were considered for the survival analyses of which two were nominally associated with ALS survival. Proton pump inhibitors (PPI) were negatively correlated with survival (HR 1.34, 95 % CI 1.04-1.73) and centrally acting muscle relaxants (CAMR) showed a positive association (HR 0.56, 95 % CI 0.39-0.81). After correcting for multiple testing, the association between CAMR and ALS survival remained significant (p = 0.03). In conclusion, this is the first study systematically evaluating potential associations between commonly used drugs and ALS disease course. We report a positive association between CAMR use and survival, which may have derived from an indication bias representing the better prognosis of the upper motor neuron predominant disease variant. However, this is still interesting since it demonstrates the sensitivity of our study design to pick up survival effects. The use of large prescription registries could thus provide a valuable basis to find clues to underlying pathophysiological mechanisms in ALS.

Epidemiology of amyotrophic lateral sclerosis and effect of riluzole on disease course.

OBJECTIVES: To assess the epidemiology of ALS in Austria and to evaluate the long-term effect of riluzole treatment on survival. METHODS: Hospital discharge and riluzole prescription databases were used to identify ALS cases from January 2008 to June 2012. Using the capture-recapture method we evaluated the incidence and prevalence of ALS and patients' survival in dependence of age, gender and riluzole treatment. RESULTS: The corrected incidence and prevalence of ALS were 3.13/100,000 person-years (95% CI, 2.77 to 3.50) and 9.14/100,000 persons (95% CI, 8.53 to 9.79), respectively. Median survival from diagnosis was 676 days (95% CI, 591 to 761). A younger age at diagnosis was associated with a longer survival. Gender did not appear to affect survival time. Riluzole therapy was associated with a survival advantage only for the initial treatment period. The adjusted hazard ratio of mortality for using riluzole increased continually over time resulting in an apparent reversal of its beneficial effect after 6 months of therapy. CONCLUSIONS: We report incidence and prevalence estimates that are on the upper end of the wide range discussed in literature. Riluzole seems to exert a beneficial effect only in the first 6 months of therapy.