The utility of ALS staging systems in a multi-ethnic patient cohort

Objective: To compare two ALS staging systems, King's clinical staging and Milano-Torino (MiToS) functional staging, using prospective data from a multi-ethnic cohort of ALS patients. Methods: The stages of disease were determined prospectively based on existing definitions. The two systems were compared for timing of stages using box plots, correspondence using chi-square tests and association using Spearman's rank correlation. Results: The distribution of stages differed between the two systems. The proportions of disease stages of the King's staging system were more evenly distributed whereas in MiToS, there was greater weight seen at the later stages of disease. At the early stages, patients moved consecutively in the MiToS staging system but not in the King's staging system where patients tended to skip stages to reach later stages. Both systems had good correlation (Spearman's rho = 0.869) and the King's stage 4 most frequently corresponded to MiToS stage 2. Conclusion: We found the King's staging was helpful in determining the stages of disease burden, whereas both were helpful in determining the time to functional dependence with MiToS further refining the levels of dependence.