Correlation between platelet serotonin levels and survival in patients with amyotrophic lateral sclerosis (ALS).

Kaplan-Meyer survival curves of patients with ALS stratified according to their platelet serotonin levels. Survival was calculated as the time period between blood sampling and death. The black line represents patients with ALS having abnormal serotonin values (serotonin <50 ng/mL, n = 22 patients); light grey line represents patients with high normal values (serotonin >100 ng/mL i.e. median of control group, n = 25 patients), and light black line patients with borderline values (50–100 ng/mL, n = 35 patients). Group comparison shows a statistically significant difference (p = 0.024 by the log-rank).