Multiple Sclerosis Society of Canada

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The natural history of secondary progressive multiple sclerosis

  • Canadian Study

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Summary
A study of over 5,000 people with MS, researchers pinpointed motor symptoms at onset (such as muscle stiffness known as spasticity) and male gender as factors associated with a faster progression from relapsing-remitting MS to secondary-progressive Researchers were funded by the National MS Society, the MS Society of Canada and others. Koch M, Kingwell E, Rieckmann P, Tremlett H; UBC MS Clinic Neurologists. J Neurol Neurosurg Psychiatry. 2010 Sep;81(9):1039-43. Epub 2010 Jul 16

Details
Of the 85% of people who are initially diagnosed with relapsing-remitting MS (RRMS), many will eventually transition to secondary-progressive MS (SPMS), which means that the disease will begin to progress more steadily, with or without any relapses. Although we have some clues, we don’t yet fully understand what triggers relapses or what causes MS to progress. The disease progression rate, severity, and specific symptoms of MS are unpredictable and vary from one person to another. Research is ongoing to find risk factors that might contribute to MS progression and markers that will help predict the course of MS, which would help greatly in making treatment decisions.

The team selected people who initially presented with RRMS from a database that contains information on people with MS at the four MS clinics in British Columbia, Canada. Information was available on 5169 people, and of these, 1821 (35%) had progressed to SPMS during the observation period from 1980 to 2003. Because this study set out to be a “natural history” study, data from people who went on disease-modifying therapies were excluded starting on the first day of their therapy.

In this untreated group, the median time to secondary progression was 21.4 years from onset, but there was a wide range of variability. Those 25% of patients with the slowest progression took more than 32 years to reach secondary progression after onset. The investigators found that having motor symptoms at onset (such as uncontrolled tremor or spasticity) and male gender were associated with a faster progression to SPMS and younger age when converting to SPMS. Median time to SPMS was 18.6 years for those with motor symptoms at onset vs. 22.0 years for those without such symptoms.   Median time to SPMS was 17.1 years for men vs. 22.7 years for women.   Also, younger age at disease onset was associated with a slower progression to SPMS, but also a younger age when SPMS began. The presumed influence of disease-modifying therapies on progression to SPMS cannot be determined from this study.

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