The Epidemiology and Pharmacoepidemiology of Multiple Sclerosis in Saskatchewan

My PhD project involved examining the epidemiology and pharmacoepidemiology of multiple sclerosis (MS) in Saskatchewan through the use of health administrative data. First, I validated a case definition of MS for administrative data, and then used the validated definition to determine the incidence and prevalence of MS in Saskatchewan. Prior to my studies, Saskatchewan was thought to have one of the highest rates of MS in Canada, but province-wide estimates were not available. I utilized the provincial MS cohort to then describe trends of healthcare utilization and the potential associations with comorbidities and use of disease-modifying therapies (DMTs) for MS using various study designs and methodologies. Both all-cause and MS-specific hospitalizations have decreased over time, but still remain higher than the general population. DMTs were associated with a minimal reduction in all-cause and MS-specific hospitalizations, and did not impact the number of physician services used. Higher rates of all-cause hospitalizations were observed in individuals that are older, have a higher comorbidity burden, and have previous hospitalizations, whereas the rate of MS-related hospitalizations increased with male sex and younger age. Comorbidity burden increased the rate of all-cause hospitalizations in a dose-response manner, but did not impact MS-related admissions. Finally, decreases in both all-cause and MS-specific hospitalizations was observed with an increase in disease duration. My research confirms that Saskatchewan has one of the highest rates of MS worldwide. While the introduction of DMTs has dramatically changed the management of MS, future research is needed to evaluate their true impact on subsequent healthcare utilization. Specific predictors, including individual comorbidities can be useful for identifying individuals with MS who are at higher risk for hospitalization, and can help guide collaborative efforts to manage the disease and prevent future hospitalizations