Multiple Sclerosis

Ruth Ann Marrie, MD, PhD, on Comorbidities in Patients With Multiple Sclerosis

Physical and mental comorbidities, such as depression and hypertension, are common among patients with multiple sclerosis (MS), even before they are diagnosed with MS. It is believed that comorbidities are one factor that contributes to the heterogeneity of the clinical course for MS as well.

Ruth Ann Marrie, MD, PhD, discussed existing knowledge regarding the effects of comorbidities on the diagnosis and treatment of MS at the Americas Committee for Treatment and Research in Multiple Sclerosis (ACTRIMS) Forum 2019.

Ruth Ann Marrie, MD, PhD, is a professor of medicine and community health sciences at the Max Rady College of Medicine at the University of Manitoba and the director of the Multiple Sclerosis Clinic in the Health Sciences Centre in Manitoba, Canada.

NEUROLOGY CON: What are the diagnostic challenges associated with patients with MS plus comorbidities?

Ruth Ann Marrie: The presence of comorbid conditions may increase the potential for misdiagnosis, due to overlapping symptoms and/or because they cause lesions on brain magnetic resonance imaging (MRI) scans. For example, diabetes, hypertension, and migraine can all cause brain lesions. In some studies, up to one-third of migraineurs with white matter lesions had a periventricular lesion. The presence of comorbid conditions can also lead to longer diagnostic delays between MS symptom onset and diagnosis.

NEURO CON: What are the treatment implications in these patients? Are there any drug-drug interactions?

RAM: Several comorbid conditions are associated with greater disability progression, including depression, diabetes, hypertension, hyperlipidemia, and ischemic heart disease. A higher burden of comorbidity is also associated with higher relapse rates and a lower likelihood of initiating disease-modifying therapy and lower persistence to disease-modifying therapy. Tolerability of therapies may also be lower in the presence of comorbidity. Depending on the specific disease-modifying therapy chosen, there may be drug interactions with the therapies used to manage the comorbidity. For example, ß-blockers and calcium channel blockers, which may be used to treat hypertension, should not be used in conjunction with fingolimod.

NEURO CON: What is the key takeaway from your session that neurologists should keep top of mind?

RAM: Comorbidity is common in MS and adversely affects outcomes. It needs to be considered when choosing interventions, whether disease-modifying or symptomatic. We need to empower people with MS to adopt positive health behaviors.


Marrie RA. Role of comorbidities in the course of MS: diagnosis and treatment implications. Paper presented at: ACTRIMS Forum 2019; February 28-March 2, 2019; Dallas, TX. Accessed February 25, 2019.