Browsing by Author "Frolkis, Alexandra"

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    Evolution of Surgery Risk in Crohn's Disease
    (2016) Frolkis, Alexandra; Kaplan, Gilaad; Jette, Nathalie; deBruyn, Jennifer
    While many individuals with Crohn’s disease require surgery for management, the risks of surgery are not well characterized in population-based studies. Advances in medical management may have influenced the risk of surgery over time. However, studies have not adequately evaluated the effect of smoking on temporal trends in surgery risk for Crohn’s disease. A mixed methodology approach was used to: 1) describe the morbidity and mortality associated with surgery in Crohn’s disease; 2) summarize the risk of first and second surgery in Crohn’s disease; 3) evaluate whether the risk of surgery has changed over time; and 4) assess whether smoking has influenced the risk of surgery in Crohn’s disease. In Alberta, postoperative morbidity (25%) and mortality (1.2%) was high for Crohn’s disease. A systematic review and meta-analysis found that the estimated pooled risk of surgery 10 years after the diagnosis of Crohn’s disease was 46.6% (95% Confidence Interval [CI] 37.7%-57.7%); however, the risk of first surgery in Crohn’s disease was significantly decreasing over time (meta-regression p- value<0.01). Another systematic review and meta-analysis identified that 10 years following the first surgery the estimated pooled risk of a second surgery was 35% (95% CI 31.8%-38.6%) and this risk was also decreasing over time (Cochran Q for subgroup comparison p-value<0.01). Finally, a nationally representative cohort showed that from 1996 to 2009 the risk of first surgery decreased significantly and the proportion of incident Crohn’s disease patients who have never smoked significantly increased annually by an estimated 3% (Risk Ratio [RR] 1.03; 95% CI 1.02-1.04). Furthermore, in older adults (>40 years at diagnosis) smoking was associated with twice the risk of surgery compared to those who did not smoke. The results of this dissertation demonstrate that surgery is associated with significant morbidity and mortality. Reassuringly, the risk of surgery is decreasing over time. In part, this decrease may be explained by fewer Crohn’s disease patients who are smokers at diagnosis. Thus, public health initiatives that reduce the prevalence of smoking in the general population may reduce the burden of Crohn’s disease.
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    The Prevalence and Incidence of Dementia Due to Alzheimer's Disease: a Systematic Review and Meta-Analysis
    (CAMBRIDGE UNIV PRESS, 2016) Fiest, Kirsten M.; Roberts, Jodie I.; Maxwell, Colleen J.; Hogan, David B.; Smith, Eric E.; Frolkis, Alexandra; Cohen, Adrienne; Kirk, Andrew; Pearson, Dawn; Pringsheim, Tamara; Venegas-Torres, Andres; Jette, Nathalie
    Background: Updated information on the epidemiology of dementia due to Alzheimer's disease (AD) is needed to ensure that adequate resources are available to meet current and future healthcare needs. We conducted a systematic review and meta-analysis of the incidence and prevalence of AD. Methods: The MEDLINE and EMBASE databases were searched from 1985 to 2012, as well as the reference lists of selected articles. Included articles had to provide an original population-based estimate for the incidence and/or prevalence of AD. Two individuals independently performed abstract and full-text reviews, data extraction and quality assessments. Random-effects models were employed to generate pooled estimates stratified by age, sex, diagnostic criteria, location (i.e., continent) and time (i.e., when the study was done). Results: Of 16,066 abstracts screened, 707 articles were selected for full-text review. A total of 119 studies met the inclusion criteria. In community settings, the overall point prevalence of dementia due to AD among individuals 60 + was 40.2 per 1000 persons (CI95%: 29.1-55.6), and pooled annual period prevalence was 30.4 per 1000 persons (CI95%: 15.6-59.1). In community settings, the overall pooled annual incidence proportion of dementia due to AD among individuals 60 + was 34.1 per 1000 persons (CI95%: 16.4-70.9), and the incidence rate was 15.8 per 1000 person-years (CI95%: 12.9-19.4). Estimates varied significantly with age, diagnostic criteria used and location (i.e., continent). Conclusions: The burden of AD dementia is substantial. Significant gaps in our understanding of its epidemiology were identified, even in a high-income country such as Canada. Future studies should assess the impact of using such newer clinical diagnostic criteria for AD dementia such as those of the National Institute on Aging-Alzheimer's Association and/or incorporate validated biomarkers to confirm the presence of Alzheimer pathology to produce more precise estimates of the global burden of AD.