Have you considered why multiple sclerosis (MS) progresses more quickly in some of your patients than in others? Many people with MS have at least one comorbidity, even at diagnosis. By ‘comorbidity’, we mean any illness that is not MS or a complication arising from MS. Such conditions may contribute to greater disability, accelerated disease progression, reduced quality of life and increased mortality. Could we improve outcomes by incorporating the prevention and management of comorbidities into the care of people with MS?