The number of people living with multiple sclerosis (MS) in British Columbia has increased over the past 18 years, but the number of new MS cases each year has held stable, a new study has found.
Researchers at the Djavad Mowafaghian Centre for Brain Health analyzed province-wide population-based administrative health data from BC to estimate the incidence and prevalence of multiple sclerosis and examine potential trends over time.
“To the best of our knowledge, our study is the first to report on the incidence of MS in BC and the only published report that examines changes in incidence or prevalence over time in BC,” says Dr. Elaine Kingwell, the lead author on the paper recently published in the Journal of Neurology.
“These data are important not only for the monitoring of time trends and comparison to estimates from other regions within and outside of Canada, but also for healthcare planning at the provincial level – this really helps to understand and plan for potential MS patient needs.”
Incidence refers to the number of new cases during a given period, while prevalence is the total number of people that are affected at a given time.
MS incidence and prevalence in BC are among the highest in the world.
- From 1996 to 2008, the annual MS incidence rate was stable (average: 7.8/100,000), but the prevalence increased significantly during the 18 year period.
- From 1991 to 2008, MS prevalence increased by 4.7 per cent on average per year, and the peak prevalence age range increased from 45-49 to 55-59 years.
As the number of new cases has not been increasing, the greater number of people living with MS is likely attributable to the longer survival with MS (longer life expectancy) as well as the earlier diagnosis of MS.
”This study is a great example of how the administrative health databases can help us monitor the distribution and time trends of a chronic disease such as MS – both reliably and cost-effectively.”
All BC residents meeting previously validated health administrative case definitions for MS were identified as incident or prevalent using hospital, physician, death, and health registration files.
Other members of the research team include Feng Zhu (UBC and VCHRI) and the CIHR Team in the Epidemiology and Impact of Comorbidity on Multiple Sclerosis (PI: Ruth Ann Marrie, University of Manitoba; co-PI: Helen Tremlett, University of British Columbia). The study was funded by the Canadian Institutes of Health Research and the Rx&D Health Research Foundation.
The BC Ministry of Health, BC Vital Statistics Agency and BC PharmaNet provided approval and support with accessing provincial data for this study; Population Data BC facilitated approval and use of the data.
Kingwell E, Zhu F, Marrie RA, Fisk JD, Wolfson C, Warren S, Profetto-Grath, Svenson LW, Jette N, Bhan V, Yu BN, Elliott, L, Tremlett, H. High incidence and increasing prevalence of multiple sclerosis in British Columbia, Canada: findings from over two decades (1991–2010) J. Neurol. 24 July, 2015: DOI 10.1007/s00415-015-7842-0