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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.
Background: This study is part of the Innovations in Data, Evidence and Applications for Persons with Neurological Conditions project to understand the strengths, preferences, and needs of persons with neurological conditions living in Canada. Objective: To estimate the prevalence and describe the sociodemographic and clinical characteristics of persons with multiple sclerosis in Canadian home care, nursing home, Complex Continuing Care hospitals, and inpatient mental health care settings. Methods: Cross-sectional study of adults aged 18 years and older with multiple sclerosis (MS; n=11,250) across Canada from 1996 through 2011 using interRAI Resident Assessment Instrument (RAI) comprehensive health assessments (RAI Minimum Data Set 2.0, RAI-Home Care, RAI-Mental Health). Comparisons were made to adults with Alzheimer’s disease and related dementias (n=260,910), other neurological conditions (n=163,578) and non-neurological conditions (n=571,567). Results: The prevalence of MS was highest in Complex Continuing Care hospitals (4125 cases per 100,000 patients), followed by home care (2020 cases per 100,000 patients), nursing homes (1424 cases per 100,000 patients), and mental health settings (138 cases per 100,000 patients). Persons with MS experienced greater impairment in the completion of activities of daily living, pain, pressure ulcers, swallowing difficulty, depression, and anxiety compared with peers within care settings. There were also significant differences between settings, particularly the degree of physical and cognitive impairment experienced by persons with MS. Conclusions: Except for mental health care settings, the prevalence of MS in community, institutional and hospital-based care settings exceeded that of the general population. These data describing the sociodemographic and clinical characteristics of persons with MS may be used to inform clinical practice and policy decisions for persons with MS across the continuum of care.
Background: Many Canadians with multiple sclerosis (MS) have recently travelled internationally to have procedures for a putative condition called chronic cerebrospinal venous insufficiency (CCSVI). Here, we describe where and when they went and describe the baseline characteristics of persons with MS who participated in this non–evidence-based medical tourism for CCSVI procedures. Methods: We conducted a longitudinal observational study that used online questionnaires to collect patient-reported information about the safety, experiences, and outcomes following procedures for CCSVI. A convenience sample of all Albertans with MS was recruited between July 2011 and March 2013. Results: In total, 868 individuals enrolled; 704 were included in this cross-sectional, baseline analysis. Of these, 128 (18.2%) participants retrospectively reported having procedures for CCSVI between April 2010 and September 2012. The proportion of participants reporting CCSVI procedures declined from 80 (62.5%) in 2010, to 40 (31.1%) in 2011, and 8 (6.3%) in 2012. In multivariable logistic regression analysis, CCSVI procedures were independently associated with longer disease duration, secondary progressive clinical course, and greater disability status. Conclusions: Although all types of people with MS pursued procedures for CCSVI, a major driver of participation was greater disability. This highlights that those with the greatest disability are the most vulnerable to unproven experimental procedures. Participation in CCSVI procedures waned over time possibly reflecting unmet expectations of treated patients, decreased media attention, or that individuals who wanted procedures had them soon after the CCSVI hypothesis was widely publicized.
Estimates of incidence and prevalence are needed to determine disease risk and to plan for health service needs. Although the province of Nova Scotia, Canada is located in a region considered to have a high prevalence of multiple sclerosis (MS), epidemiologic data are limited.
We aimed to validate an administrative case definition for MS and to use this to estimate the incidence and prevalence of MS in Nova Scotia.
We used provincial administrative claims data to identify persons with MS. We validated administrative case definitions using the clinical database of the province's only MS Clinic; agreement between data sources was expressed using a kappa statistic. We then applied these definitions to estimate the incidence and prevalence of MS from 1990 to 2010.
We selected the case definition using ≥7 hospital or physician claims when >3 years of data were available, and ≥3 claims where less data were available. Agreement between data sources was moderate (kappa = 0.56), while the positive predictive value was high (89%). In 2010, the age-standardized prevalence of MS per 100,000 population was 266.9 (95% CI: 257.1- 277.1) and incidence was 5.17 (95% CI: 3.78-6.56) per 100,000 persons/year. From 1990-2010 the prevalence of MS rose steadily but incidence remained stable.
Administrative data provide a valid and readily available means of estimating MS incidence and prevalence. MS prevalence in Nova Scotia is among the highest in the world, similar to recent prevalence estimates elsewhere in Canada.
The Expanded Disability Status Scale (EDSS) represents the most widely accepted measure of disease progression in multiple sclerosis (MS), and is used in many natural history studies. This chapter discusses natural history of relapsing onset MS, primary progressive MS, changes in natural history and impact on clinical trial design, traditional prognostic factors, and other factors which may influence prognosis such as race, comorbid diseases, and health behaviors. Pharmacoepidemiological studies using real world data derived from clinical practice represent a cost-effective means of evaluating the long-term effectiveness of immunomodulatory drug treatments for MS. Along with evidence from the basic sciences, epidemiological studies can provide insights into potentially novel treatments, as well as the rationale and hypotheses for testing these treatments in clinical trials. For example, vitamin D and estrogen are being evaluated in clinical trials based partly on epidemiological observations. Heterogeneity remains the hallmark of MS.
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