Skip to main content
×
×
Home

Establishing the Incidence and Prevalence of Multiple Sclerosis in Saskatchewan

  • Lina H. Al-Sakran (a1), Ruth Ann Marrie (a2), David F. Blackburn (a1), Katherine B. Knox (a3) and Charity D. Evans (a1)...
Abstract

Objective: To validate a case definition of multiple sclerosis (MS) using health administrative data and to provide the first province-wide estimates of MS incidence and prevalence for Saskatchewan, Canada. Methods: We used population-based health administrative data between January 1, 1996 and December 31, 2015 to identify individuals with MS using two potential case definitions: (1) ≥3 hospital, physician, or prescription claims (Marrie definition); (2) ≥1 hospitalization or ≥5 physician claims within 2 years (Canadian Chronic Disease Surveillance System [CCDSS] definition). We validated the case definitions using diagnoses from medical records (n=400) as the gold standard. Results: The Marrie definition had a sensitivity of 99.5% (95% confidence interval [CI] 92.3-99.2), specificity of 98.5% (95% CI 97.3-100.0), positive predictive value (PPV) of 99.5% (95% CI 97.2-100.0), and negative predictive value (NPV) of 97.5% (95% CI 94.4-99.2). The CCDSS definition had a sensitivity of 91.0% (95% CI 81.2-94.6), specificity of 99.0% (95% CI 96.4-99.9), PPV of 98.9% (95% CI 96.1-99.9), and NPV of 91.7% (95% CI 87.2-95.0). Using the more sensitive Marrie definition, the average annual adjusted incidence per 100,000 between 2001 and 2013 was 16.5 (95% CI 15.8-17.2), and the age- and sex-standardized prevalence of MS in Saskatchewan in 2013 was 313.6 per 100,000 (95% CI 303.0-324.3). Over the study period, incidence remained stable while prevalence increased slightly. Conclusion: We confirm Saskatchewan has one of the highest rates of MS in the world. Similar to other regions in Canada, incidence has remained stable while prevalence has gradually increased.

Établir l’incidence et la prévalence de la sclérose en plaques en Saskatchewan. Objectif: Au moyen de données administratives relatives à la santé, valider une définition des cas de sclérose en plaques (SP) et fournir les premières estimations de l’incidence et de la prévalence de la SP en Saskatchewan. Méthodes: Les données administratives que nous avons utilisées se rapportaient à la période allant du 1er janvier 1996 au 31 décembre 2015 et étaient relatives à la population de la Saskatchewan. Nous avons ainsi cherché à identifier des individus atteints de SP au moyen de deux définitions de cas potentielles : (1) ≥3 demandes de remboursement d’un hôpital, actes facturés par un médecin ou demandes de règlement relatives à un médicament sur ordonnance (définition de Marrie); (2) ≥1 hospitalisation ou ≥5 actes facturés par un médecin au cours de deux ans (définition du Système canadien de surveillance des maladies chroniques [SCSMC]). À titre de norme de référence, nous avons ensuite validé ces définitions de cas en nous référant à des diagnostics établis dans des dossiers médicaux (n=400). Résultats: La définition de Marrie a montré une sensibilité de 99,5 % (IC 95 %, 92,3-99,2), une spécificité de 98,5 % (IC 95 %, 97,3-100,0), une valeur prédictive positive (VPP) de 99,5 % (IC 95 %, 97,2-100,0) et une valeur prédictive négative (VPN) de 97,5 % (IC 95 %, 94,4-99,2). La définition du SCSMC a quant à elle montré une sensibilité de 91,0 % (IC 95 %, 81,2-94,6), une spécificité de 99,0 % (IC 95 %, 96,4-99,9), une VPP de 98,9 % (IC 95 %, 96,1-99,9) et une VPN de 91,7 % (IC 95 %, 87,2-95,0). À l’aide de la définition de Marrie, plus sensible, il appert que l’incidence moyenne annuelle ajustée de SP par 100 000 habitants était, entre 2001 et 2013, de 16,5 (IC 95 %, 15,8-17,2). En ce qui regarde la prévalence standardisée de SP selon l’âge et le sexe en Saskatchewan, elle était de 313,6 par 100 000 habitants en 2013 (IC 95 %, 303,0-324,3). Il est à noter, au cours de la période étudiée, que l’incidence de SP est demeurée stable alors que la prévalence s’est accrue légèrement. Conclusions: Nous pouvons confirmer que la Saskatchewan possède un des taux de SP parmi les plus élevés au monde. De 1996 à 2015, l’incidence de cette maladie est demeurée stable alors que sa prévalence a légèrement augmenté. Il s’agit là d’une constatation similaire à celles qui caractérisent d’autres régions au Canada.

  • View HTML
    • Send article to Kindle

      To send this article to your Kindle, first ensure no-reply@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about sending to your Kindle. Find out more about sending to your Kindle.

      Note you can select to send to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

      Find out more about the Kindle Personal Document Service.

      Establishing the Incidence and Prevalence of Multiple Sclerosis in Saskatchewan
      Available formats
      ×
      Send article to Dropbox

      To send this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Dropbox.

      Establishing the Incidence and Prevalence of Multiple Sclerosis in Saskatchewan
      Available formats
      ×
      Send article to Google Drive

      To send this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your <service> account. Find out more about sending content to Google Drive.

      Establishing the Incidence and Prevalence of Multiple Sclerosis in Saskatchewan
      Available formats
      ×
Copyright
This is an open access article, distributed under the terms of the creative commons attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Corresponding author
Correspondence to: Charity D. Evans, College of Pharmacy and Nutrition, University of Saskatchewan, 104 Clinic Place, Saskatoon, SK, Canada S7N 2Z4. Email: charity.evans@usask.ca
References
Hide All
1. Multiple Sclerosis Federation. Atlas of MS database. 2013. Available at: http://www.atlasofms.org/index.aspx. Accessed May 19, 2015.
2. Ebers, GC. Environmental factors and multiple sclerosis. Lancet Neurol. 2008;7(3):268-277.
3. Poppe, AY, Wolfson, C, Zhu, B. Prevalence of multiple sclerosis in Canada: a systematic review. Can J Neurol Sci. 2008;35(5):593-601.
4. Marrie, R, Yu, N, Blanchard, J, et al. The rising prevalence and changing age distribution of multiple sclerosis in Manitoba. Neurology. 2010;74(6):465-471.
5. Public Health Agency of Canada. Canadian Chronic Disease Surveillance System 1996/1997-2011/2012. 2016. Available at: http://open.canada.ca/data/en/dataset/9525c8c0-554a-461b-a763-f1657acb9c9d. Accessed February 21, 2017.
6. Hader, WJ, Yee, IM. Incidence and prevalence of multiple sclerosis in Saskatoon, Saskatchewan. Neurology. 2007;69(12):1224-1229.
7. Beck, CA, Metz, LM, Svenson, LW, et al. Regional variation of multiple sclerosis prevalence in Canada. Mult Scler. 2005;11(5):516-519.
8. Government of Saskatchewan. Saskatchewan population reports. 2017. Available at: http://www.stats.gov.sk.ca/pop/. Accessed September 26, 2017.
9. Downey W, Stang M, Beck P, Osei W, Nichol JL. Health services databases in Saskatchewan. In: Strom BL, editor. Pharmacoepidemiology. Chichester: John Wiley & Sons, 2006, p. 295-310.
10. Poser, CM, Paty, DW, Scheinberg, L, et al. New diagnostic criteria for multiple sclerosis: guidelines for research protocols. Ann Neurol. 1983;13(3):227-231.
11. McDonald, WI, Compston, A, Edan, G, et al. Recommended diagnostic criteria for multiple sclerosis: guidelines from the international panel on the diagnosis of multiple sclerosis. Ann Neurol. 2001;50(1):121-127.
12. Polman, CH, Reingold, SC, Edan, G, et al. Diagnostic criteria for multiple sclerosis: 2005 revisions to the “Mcdonald criteria”. Ann Neurol. 2005;58(6):840-846.
13. Polman, CH, Reingold, SC, Banwell, B, et al. Diagnostic criteria for multiple sclerosis: 2010 revisions to the Mcdonald criteria. Ann Neurol. 2011;69(2):292-302.
14. Canadian Institute for Health Information. Rehabilitation. 2016. Available at: https://www.cihi.ca/en/types-of-care/hospital-care/rehabilitation. Accessed May 5, 2016.
15. Marrie, RAYN, Blanchard, J, Leung, S, Elliot, L. The rising prevalence and changing age distribution of multiple sclerosis in Manitoba. Neurology. 2010;74(6):465-471.
16. Wijnands, JM, Kingwell, E, Zhu, F, et al. Health-care use before a first demyelinating event suggestive of a multiple sclerosis prodrome: a matched cohort study. Lancet Neurol. 2017;16(6):445-451.
17. Evans, C, Marrie, RA, Zhu, F, et al. Adherence to disease‐modifying therapies for multiple sclerosis and subsequent hospitalizations. Pharmacoepidemiol Drug Saf. 2017;26(6):702-711.
18. Evans, C, Marrie, RA, Zhu, F, et al. Adherence and persistence to drug therapies for multiple sclerosis: a population-based study. Mult Scler Relat Disord. 2016;8:78-85.
19. Marrie, RA, Elliott, L, Marriott, J, et al. Effect of comorbidity on mortality in multiple sclerosis. Neurology. 2015;85(3):240-247.
20. Kingwell, EZF, Marrie, RA, Fisk, JD, et al. High incidence and increasing prevalence of multiple sclerosis in British Columbia, Canada: findings from over two decades (1991-2010). J Neurol. 2015;262(10):2352-2363.
21. Marrie, RAFJ, Stadnyk, KJ, Yu, BN, et al. The incidence and prevalence of multiple sclerosis in Nova Scotia, Canada. Can J Neurol Sci. 2013;40(6):824-831.
22. Widdifield, J, Ivers, NM, Young, J, et al. Development and validation of an administrative data algorithm to estimate the disease burden and epidemiology of multiple sclerosis in Ontario, Canada. Mult Scler. 2015;21(8):1045-1054.
23. Dohoo, IR, Martin, SW, Stryhn, H. Methods in epidemiologic research. Charlottetown: VER Inc.; 2012.
24. Amankwah, N, Marrie, RA, Bancej, C, et al. Multiple sclerosis in Canada 2011 to 2031: results of a microsimulation modelling study of epidemiological and economic impacts. Chronic Dis Inj Can. 2017;37(2):37-48.
25. Government of Canada. Multiple sclerosis in Canada 2011 to 2031: results of a microsimulation modelling study of epidemiological and economic impacts - HPCDP: Volume 37-2. 2017. Available at: https://www.canada.ca/en/public-health/services/reports-publications/health-promotion-chronic-disease-prevention-canada-research-policy-practice/vol-37-no-2-2017/multiple-sclerosis-canada-2011-2031-results-microsimulation-modelling-study-epidemiological-economic-impacts.html. Accessed September 27, 2017.
26. McGuigan, C, Dunne, C, Crowley, J, et al. Population frequency of HLA haplotypes contributes to the prevalence difference of multiple sclerosis in Ireland. J Neurol. 2005;252(10):1245-1248.
27. Marrie, RA, Cutter, G, Tyry, T, et al. Changes in the ascertainment of multiple sclerosis. Neurology. 2005;65(7):1066-1070.
28. Warren, SA, Svenson, LW, Warren, KG. Contribution of incidence to increasing prevalence of multiple sclerosis in Alberta, Canada. Mult Scler. 2008;14(7):872-879.
29. Koch-Henriksen, N, Sorensen, PS. The changing demographic pattern of multiple sclerosis epidemiology. Lancet Neurol. 2010;9(5):520-532.
30. Ng, R, Bernatsky, S, Rahme, E. Observation period effects on estimation of systemic lupus erythematosus incidence and prevalence in Quebec. J Rheumatol. 2013;40(8):1334-1336.
31. Kingwell, E, van der Kop, M, Zhao, Y, et al. Relative mortality and survival in multiple sclerosis: findings from British Columbia, Canada. J Neurol Neurosurg Psychiatry. 2012;83(1):61-66.
32. Warren, SA, Janzen, W, Warren, KG, et al. Multiple sclerosis mortality rates in Canada, 1975-2009. Can J Neurol Sci. 2016;43(1):134-141.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Canadian Journal of Neurological Sciences
  • ISSN: 0317-1671
  • EISSN: 2057-0155
  • URL: /core/journals/canadian-journal-of-neurological-sciences
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Keywords

Type Description Title
WORD
Supplementary materials

Al-Sakran et al. supplementary material
Al-Sakran et al. supplementary material 1

 Word (32 KB)
32 KB

Metrics

Altmetric attention score

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed