Figure 1. Decision model.

Treatment-naive patients with relapsing-remitting multiple sclerosis (RRMS) choose 1 of the 3 representative disease-modifying drugs: natalizumab, fingolimod, or glatiramer acetate (A, left). From a baseline Expanded Disability Status Scale (EDSS) state, each year, a patient will remain in the same EDSS state (stable), move to an improved state, move to a worse state (disability worsening), or die (B, right). The probability of disability worsening on each drug is calculated with relative risk data from the most recently published randomized controlled trial (appendix e-1 and table e-1). Patients treated with natalizumab or fingolimod have a risk of developing progressive multifocal leukoencephalopathy (PML). Patients who develop PML either die (PML mortality) or survive with an increase in disability (PML morbidity) by the start of the following year.