Multiple Sclerosis

What is it?

Multiple sclerosis is considered to be an immune-mediated disease of the central nervous system. The disease affects the protective covering of the nerve (myelin) and damages the nerve fibers (axons). The result may be a wide variety of symptoms, depending on what parts of the central nervous system are affected.

The cause of multiple sclerosis remains unknown. However, it is considered to be a complex disease in which one or more environmental factors act together in a genetically susceptible individual to cause disease. The genetic factors most consistently associated with multiple sclerosis involve the HLE allele. Environmental factors of particular interest include Epstein-Barr virus infection, vitamin D insufficiency, smoking and obesity.

Multiple sclerosis is the most common non-traumatic cause of disability in young adults. Most affected individuals present with symptoms between the ages of 20 and 40 years. Women are affected nearly three times as often as men. The disease is variable from one person to another, and the ability to predict outcomes is limited. Most affected individuals present with an initially relapsing-remitting course. Symptoms are stable between relapses, but most individuals will develop gradual disability progression (secondary progressive multiple sclerosis). About 15% of persons have a gradual progression of disability from onset (primary progressive multiple sclerosis). Ultimately, most patients experience a constellation of symptoms, including weakness, sensory symptoms, bowel and bladder dysfunction, fatigue, spasticity, pain and cognitive impairment. Multiple sclerosis adversely affects employment and social relationships, and burdens the affected individual, their family, the health care system and society. Quality of life is lower in persons with multiple sclerosis compared to the general population and persons with other chronic diseases.

Treatment involves treatment of acute relapses, use of disease-modifying therapies and chronic symptom management. While there have been major advancements in disease-modifying medications that reduce the risk of relapses and delay progression in relapsing forms of multiple sclerosis, there are currently no approved disease-modifying therapies for primary progressive multiple sclerosis.

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  • number of people in Ontario with the disorder
  • age of people with the disorder
  • sex ratio of people with the disorder
  • what other brain disorders commonly co-occur
  • overlap with mental health and addictions health system use
  • costs & cost drivers associated with health system use

Sex breakdown

On April 1, 2019 females accounted for 72% of the 31,470 Ontarians identified with multiple sclerosis.

Age breakdown

On April 1, 2019 the majority of people with multiple sclerosis were between the ages of 40 and 64 years, with 77% of people being under the age of 65. The mean age of a person with multiple sclerosis was 54 ± 14 years.

Number of people

Incidence is the number of people newly diagnosed with a disorder within a given time period while prevalence is the number of people existing with the disorder at a given time.

The incidence and prevalence of Ontarians with multiple sclerosis are depicted in orange and blue, respectively. Between 2011 and 2019, incidence changed from 12.84 to 13.21 per 100,000 people and prevalence increased from 243.03 to 273.86 per 100,000 people.

In total, the number of people with multiple sclerosis increased from 24,843 in 2011 to 31,470 people in 2019.

Cost drivers

In 2019, the average total cost to the health system for an Ontarian with multiple sclerosis was 1.3X more for an incident case than a prevalent case. Cost relationship is indicated by total box size. The largest cost driver of incident cases was attributable to hospital care (37%), while hospital care (22%) and long term care (20%) had the highest costs for prevalent cases.

The average total health care costs for a person with multiple sclerosis (prevalent case) for 1 year are 5X higher for adults and 2X higher for seniors compared to the average Ontarian.

Cost driver breakdown

Overall, health care costs (in Canadian dollars, 2019) for people with multiple sclerosis are higher for senior (65+ years) population compared to adults (20 - 64 years) and are also higher for males than females. The cost drivers, those services that drive health care costs, vary depending on age and sex. Amongst adults, drugs and hospital care account for the largest cost drivers at 25% and 22% of all costs respectively, while in seniors long term care and hospital care account for the largest cost drivers at 30% and 22% respectively. Hospital care is the largest cost driver in males representing 25% health care costs while long term care and hospital care drive female costs at 21% each.

Co-occurring brain disorders

Of those individuals who were identified as having multiple sclerosis between 2011 and 2019, 32% (blue) were also identified as having one of the other 12 brain disorders studied using health administrative data. Traumatic brain injury or concussion was the top co-occurring brain disorder, with 10% of those with brain injury also having multiple sclerosis, followed by 8% having had a stroke, and 7% having dementia.

Mental health

Of those individuals who were identified as having multiple sclerosis in 2019, their visit rates for mental health and addictions related services were between 1.9X to 2.5X greater than the general Ontario population, depending on visit type.