Browsing by Author "Rabi, Doreen M"

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    Expanding the evidence of endovascular treatment for acute ischemic stroke: patient–centered outcomes, population–level impact, and patients presenting with mild stroke symptoms
    (2020-10-06) Zerna, Anna Charlotte; Hill, Michael D; Demchuk, Andrew M; Rabi, Doreen M
    Endovascular treatment (EVT) for anterior circulation acute ischemic stroke due to large?vessel occlusion is the new standard of care resulting in reduced disability compared to medical treatment. Practice guidelines recommend the use of EVT but can only speak to the evidence provided by clinical trials and might not be appropriate when complex medical decisions need to consider the heterogeneity of patients in routine clinical care. Brought about by the limitations of the clinical trials, the work described in this doctoral thesis aimed to assess the long–term sustainability of efficacy of EVT, the utilization of post–stroke outcomes that are patient–centered and more meaningful to affected individuals, and the effectiveness of EVT in patient populations that have not been part of clinical trial cohorts. These are commonly older patients with comorbidities and patients presenting with mild stroke symptoms. The miFUNCTION scale was shown to display greater granularity in the mild to moderately–severe disability range post–stroke compared to the modified Rankin Scale and thus provide more insight into the patient's ability and capacity to engage in meaningful life roles after EVT. In a population–based analysis, adult patients undergoing EVT spent on average more than one week longer at home within the first 90 days compared with patients receiving medical treatment. Home?time was used as a novel, health?economic, and patient?centered outcome. For patients presenting with mild symptoms, EVT resulted in similar 90–day outcomes compared to medical management despite an increased risk of neurological deterioration at 24 hours. Due to uncertainty regarding the risk–benefit–ratio, a well–designed clinical trial will need to establish how best to treat these patients. Overall, the work described here provides greater understanding of how the benefits and risks of EVT might vary across the population and differ from the rather homogenous patient cohort that has been assessed in the clinical trials. The results of this research will be meaningful to patients who experience acute ischemic strokes caused by large vessel occlusion and also aid with economic and regulatory decisions to more broadly offer and organize EVT across Alberta and beyond.
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    Measuring medication adherence in patients with incident hypertension: a retrospective cohort study
    (2017-02-13) Tang, Karen L; Quan, Hude; Rabi, Doreen M
    Abstract Background Though pharmacy claims data are commonly used to study medication adherence, there remains no standard operational definition for adherence especially for patients on multiple medications. Even when studies use the same terminology, the actual methods of calculating adherence can differ drastically. It is unclear whether the use of different definitions results in different conclusions regarding adherence and associated outcomes. The objective of our study was to compare adherence rates and associations with mortality using different operational definitions of adherence, and using various methods of handling concurrent medication use. Methods We conducted a cohort study of patients aged ≥65 years from Manitoba, Canada, with incident hypertension diagnosed in 2004 and followed to 2009. We calculated adherence rates to anti-hypertensive medications using different operational definitions of medication adherence (including interval and prescription based medication possession ratios [MPR] and proportion of days covered [PDC]). For those on concurrent medications, we calculated adherence rates using the different methods of handling concurrent medication use, for each definition. We used logistic regression to determine the association between adherence and mortality for each operational definition. Results Among 2199 patients, 24.1% to 90.5% and 71.2% to 92.7% were considered adherent when using fixed interval and prescription-based interval medication possession ratios [MPRi and MPRp] respectively, depending on how concurrent medications were handled. Adherence was inversely associated with death, with the strongest association for MPRp measures. This association was significant only when considering adherence to any anti-hypertensive [aOR 0.70, 95% CI 0.51, 0.97], or when the mean of the class-specific MPRp’s [adjusted OR 0.71, 95% CI 0.53, 0.95] was used. No significant association existed when the highest or lowest class-specific MPRp was used as the adherence estimate. Conclusion The range of adherence estimates varies widely depending on the operational definition used. Given less variation in adherence rates and their stronger association against mortality, we recommend using prescription-based MPR’s to define medication adherence.