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Course & Prognosis

Untreated MS is a progressive condition. It is uncommon for people with MS not to progress to disability over time. The rate at which this happens has been the subject of much conjecture, but recent studies have clarified this considerably. A large study of the natural history of the condition has shown that a relapsing course is followed by chronic progression in around 80% of cases within 20 years.1 While there is considerable individual variation in the rate of progression, this process is relatively typical in most patients and seems likely to be degenerative in nature.

Primary progressive MS (PPMS) appears to proceed to disability faster than other forms, although again there is considerable variation. One large study showed that a quarter of patients with PPMS needed a cane by 7. 3 years after diagnosis; in contrast a quarter still didn’t need one at 25 years.2

A recent study suggested that disability progression in MS is actually slower than previously reported.3 It showed that in a group of 2,837 patients with all forms of MS, only 21% needed a cane 15 years after disease onset, and by age 50, 28% required a cane. These figures may reflect the effect MRI has in making the diagnosis in people who may previously not have been diagnosed at all, and in making the diagnosis earlier. It did however show that men progressed 38% more quickly than women.

Another US study reported similar findings.4 In 115 patients in one county, the median time from diagnosis to EDSS score of 3 was 17 years, and to a score of 6 was 24 years. Twenty years after onset, only 25% of those with relapsing-remitting MS had EDSS scores of 3 or more. The median time from diagnosis to EDSS score of 6 for the secondary progressive groups was 10 years and for the primary progressive group was 3 years. Once an EDSS score of 3 was reached, progression of disability was more likely and more rapid.

A large study of 1,844 patients suggested that MS is really one disease with progressive illness, whether primary or secondary, essentially following the same course.5,6 For most people with MS, disability landmarks were reached at about the same age. For instance, patients required a cane on average at about the age of 63, give or take a couple of years, regardless of the initial course. As in previous studies, women reached these milestones later than men. The authors suggested that age-related degeneration may be an important mediator of this progression in people with MS.

It is important to note that, according to the best available evidence, the course of MS appears to be altered a little by regular medication, whereas lifestyle modifications such as diet, sunlight, exercise, and meditation are more likely to have a major impact.
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Prognosis

The medical literature suggests that the only way to predict how you will go is to observe how you go. In other words, giving a prognosis at the outset is impossible. An Australian study found that people have a worse prognosis if they are older at the onset of the disease, have a progressive disease course, have symptoms at onset which are multiple, motor or balance, and have a short time to their first relapse, but these are generalisations.7 One of the few constant findings in the MS literature is that the ‘sooner to cane, sooner to wheelchair’.2

There are many myths about the long term outlook for people with MS. It used to be said that people with MS did not have a shortened life span compared with the general population, and that no-one dies of MS. In fact, it is clear that people with MS die considerably earlier than those without the disease, at least if they do nothing about the illness. A 2004 Danish study analysing a registry of people diagnosed in that country with MS since 1948 showed that people with MS die around 10 years earlier than the general population.8 They also showed that over half (56%) died from MS. An encouraging feature was that the excess death rate for those with MS compared with the general population fell by the end of the study to about half the rate it was in the mid-1900s. It is likely this represents the fact the diagnosis is being made earlier and in more people these days, and possibly the effect of the newer disease-modifying drugs.

One group of patients who seem to have quite a benign course is those whose first symptoms are visual, that is those who get optic neuritis.9 This group of people seems to develop only mild disability over the 10 years after the diagnosis of optic neuritis.
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  1. Kremenchutzky M, Rice GP, Baskerville J, et al. The natural history of multiple sclerosis: a geographically based study 9: Observations on the progressive phase of the disease. Brain 2006
  2. Tremlett H, Paty D, Devonshire V. The natural history of primary progressive MS in British Columbia, Canada. Neurology 2005; 65:1919-1923
  3. Tremlett H, Paty D, Devonshire V. Disability progression in multiple sclerosis is slower than previously reported. Neurology 2006; 66:172-177
  4. Pittock SJ, Mayr WT, McClelland RL, et al. Disability profile of MS did not change over 10 years in a population-based prevalence cohort. Neurology 2004; 62:601-606
  5. Confavreux C, Vukusic S. Natural history of multiple sclerosis: a unifying concept. Brain 2006
  6. Confavreux C, Vukusic S. Age at disability milestones in multiple sclerosis. Brain 2006
  7. Hammond SR, McLeod JG, Macaskill P, et al. Multiple sclerosis in Australia: prognostic factors. J Clin Neurosci 2000; 7:16-19.
  8. Bronnum-Hansen H, Koch-Henriksen N, Stenager E. Trends in survival and cause of death in Danish patients with multiple sclerosis. Brain 2004; 11:11
  9. Neurologic Impairment 10 Years After Optic Neuritis. Arch Neurol 2004; 61:1386-1389