Change in disease severity as measured by the ALS Functional Rating Scale-Revised (ALSFRS-R) total score using a Bayesian repeated measures model that accounts for loss to follow-up due to mortality. Each of 12 questions assessing distinct functional ability is scored from 4 (normal) to 0 (no ability), with a maximum total score of 48 and a minimum total score of 0. Patients with higher scores have more physical function.

Mortality is defined as death or death equivalent. A participant is determined to meet the criteria of death equivalent if permanent assisted ventilation (PAV) is used for more than 22 hours per day for more than seven days in a row. The rate of mortality was estimated from a Bayesian shared-parametric model that assumed exponentially distributed survival times.