Institute of Clinical Evaluative science

Toronto, Canada

Institute of Clinical Evaluative science

Toronto, Canada
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Cheng I.,Sunnybrook Health science Center | Kiss A.,Institute of Clinical Evaluative science | Lilge L.,University of Toronto
Wilderness and Environmental Medicine | Year: 2013

Objective To determine the level of UV radiation at extreme altitude and to assess the effect it has on the skin. Methods Fifteen expeditioners and 10 Sherpas were assessed during a climbing expedition on the north side of Mt Everest (8848 m). UV exposure measurement and diffuse skin reflectance spectrophotometry were performed at the beginning and end of the expedition. Results Over the course of the expedition, the expeditioners and Sherpas received a median dose of 93.6 (interquartile range [IQR], 61.0-102.8) and 102.5 (IQR, 72.2-117.8) minimal erythemal doses (MEDs) of UV radiation. The maximum dosage exceeded 106 ± 1.4 MEDs. Using reflectance spectrophotometry, expeditioner and Sherpa melanin-hemoglobin increased by 83.6% (IQR, -1.5 to 89.8%) and 24.7% (IQR, -22.4 to 61.5%) for exposed skin, respectively. The amount of subcutaneous lipid-water decreased by a factor of 196.6 (IQR, 52.1-308.4) and 46.7 (IQR, 1.8-1156.5), for expeditioners and Sherpas, respectively. Conclusions This expedition's participants received massive doses of UV radiation during their time at high altitude. In many individuals this was similar to the annual exposure of northern European office-workers (100 MEDs). Diffuse skin reflectance spectroscopy revealed considerable subcutaneous lipid loss, skin dehydration, and increased melanin in keeping with these levels of exposure. © 2013 Wilderness Medical Society.


Vicus D.,Sunnybrook Health science Center | Vicus D.,Institute of Clinical Evaluative science | Sutradhar R.,Institute of Clinical Evaluative science | Lu Y.,Institute of Clinical Evaluative science | And 4 more authors.
Gynecologic Oncology | Year: 2014

Objective To estimate the effect of cervical cancer screening on mortality from cervical cancer in women between the ages of 20 and 69 residing in Ontario by 5 year age groups. Methods An Ontario population based case-control study of women between ages 20 and 69 was performed. Cases were women who were diagnosed with cervical cancer between January 1, 1998 and December 31, 2008 who died from cervical cancer within this period. Controls were women without a diagnosis of cervical cancer between January 1, 1998 and December 31, 2008 who were alive on the case's date of death. Exposure was defined as cervical cytology history. Conditional logistic regression was used to estimate the strength of association between mortality from cervical cancer and screening in 5 year incremental age intervals. Results We identified 1052 cases and 10,494 controls. Less than 2.5% of women who died from cervical cancer were under the age of 30. Cervical cancer screening performed 3-36 months prior to the date of diagnosis was found to be protective of mortality from cervical cancer in women over the age of 30 (odds ratio = 0.28-0.60; p < 0.05 in all strata). In women under the age of 30 cervical cancer screening was not found to be protective of mortality from cervical cancer (odds ratio = 1.58-2.43; non significant). Conclusion No association between cervical cancer screening and mortality from cervical cancer under the age of 30 was found. This could be due to there being a small or having no effect or due to the fact that mortality from cervical cancer under the age of 30 is extremely rare. © 2014 Elsevier Inc.


Grunfeld E.,Ontario Cancer Institute | Grunfeld E.,University of Toronto | Earle C.C.,Ontario Cancer Institute | Earle C.C.,Institute of Clinical Evaluative science | Stovall E.,National Coalition for Cancer Survivorship
Cancer Epidemiology Biomarkers and Prevention | Year: 2011

Awareness has grown over the past few years that needs specific to cancer survivors have long been neglected. Clinicians and policy makers continue to struggle, however, with exactly how to address these needs. We present a comprehensive framework for survivorship research and couple it with a model for translating research into policy, using two examples for illustration. ©2011 AACR.


Pongmoragot J.,St Michaels Hospital | Saposnik G.,St Michaels Hospital | Saposnik G.,Institute of Clinical Evaluative science | Saposnik G.,University of Toronto
Current Atherosclerosis Reports | Year: 2012

Cerebral venous thrombosis (CVT) is an uncommon cause of stroke with the incidence of 0.5 % from all strokes. The clinical presentation with cerebral hemorrhage constitutes a diagnostic challenge. Approximately one- third of CVT patients developed intracerebral hemorrhage (ICH). Associated factors include older age, female sex, acute onset (48 h), headache, decreased level of consciousness, seizure, elevated blood pressure and papilledema. MRI and MR venogram is the most recommend diagnostic modality in CVT. Anticoagulation therapy is the most commonly accepted treatment even in patients with ICH related CVT. Mechanical thrombectomy/thrombolysis may be considered in patients with neurological deterioration despite intensive medical treatment. Intracerebral hemorrhage in the context of CVT is usually associated with poorer outcomes compared to CVT without ICH. © Springer Science+Business Media, LLC 2012.


Finlayson O.,University of Toronto | Kapral M.,University of Toronto | Kapral M.,Institute of Clinical Evaluative science | Hall R.,Institute of Clinical Evaluative science | And 4 more authors.
Neurology | Year: 2011

Objectives: Pneumonia is the most common medical complication after stroke. Although several risk factors have been reported, the role of common comorbidities in the development of pneumonia is not well established. Moreover, there is discrepancy in the literature regarding the impact of pneumonia on stroke outcomes. Methods: This is a multicenter retrospective cohort study including consecutive patients with ischemic stroke admitted to Regional Stroke Centers participating in the Registry of Canadian Stroke Network in July 2003-March 2007. Pneumonia was defined as a complication that occurred within the first 30 days of the stroke and was confirmed radiographically. The main outcome measure was adjusted 30-day mortality. Secondary outcomes were adjusted 7- and 365-day mortality, institutionalization, length of stay, and modified Rankin score on discharge. We also assessed the impact of organized stroke care on pneumonia development and mortality. Results: Overall, 8,251 patients were included in the study. Stroke-associated pneumonia was observed in 587 patients (7.1%). Pneumonia increased 30-day (odds ratio [OR] 2.2 [95% confidence interval (CI) 1.8-2.7]) and 1-year mortality (OR 3.0 [95% CI 2.5-3.7]), but not 7-day mortality. Pneumonia was associated with poor functional outcome. Higher access to organized inpatient care resulted in a reduction of 30-day mortality (OR 0.50 [95% CI 0.41-0.61]). Older age, male sex, stroke severity, dysphagia, chronic obstructive pulmonary disease, coronary artery disease, nonlacunar ischemic stroke, and preadmission dependency were independent predictors of pneumonia. Conclusions: Development of pneumonia after stroke was associated with mortality at 30 days and 1 year, longer length of stay, and dependency at discharge. Patients who received more inpatient stroke services had reduced mortality after pneumonia. © 2011 by AAN Enterprises, Inc.


Kirst M.,University of Toronto | Mecredy G.,University of Toronto | Mecredy G.,Institute of Clinical Evaluative science | Chaiton M.,University of Toronto
Canadian Journal of Public Health | Year: 2013

OBJECTIVES: Tobacco use co-morbidities, including co-occurring tobacco use, substance use and mental health problems, are a serious public health issue that has implications for treatment and policy. However, not enough is known about the prevalence of various types of tobacco use co-morbidities among the Canadian population. The purpose of this study was to increase understanding of the extent of this issue through an examination of prevalence and correlates of tobacco use co-morbidities in Canada. METHODS: We undertook a series of comprehensive secondary analyses of population survey data from the Canadian Community Health Survey (CCHS) and the Canadian Alcohol and Drug Monitoring Survey (CADUMS). Data were analyzed for 123,846 individuals from the CCHS and 13,581 individuals from the CADUMS. Substance use and mental health variables were compared by smoking status, with chi-square tests. Multivariate logistic regression models were fit to quantify the association between smoking, substance use and mental health issues, adjusting for age, sex, and family income. RESULTS: Prevalence of problematic alcohol and illicit drug use was significantly higher among current smokers than non-smokers. Co-morbid mental health problems were also elevated among current smokers, and co-morbidities varied by age and gender. While smokers of all ages and genders were more likely to report problematic substance use and poor mental health, the effect of smoking status was significantly larger among youth. CONCLUSION: Smoking in Canada is associated with problematic use of alcohol and illicit drugs, as well as co-morbid mental health problems. Youth tobacco use co-morbidities are at a concerning level, especially among young female smokers. More research on this issue in the Canadian context is needed, as well as the development of integrated interventions tailored to treat smokers with co-morbidities, particularly youth. © Canadian Public Health Association, 2013. All rights reserved.


Pongmoragot J.,University of Toronto | Parthasarathy S.,University of Toronto | Selchen D.,University of Toronto | Saposnik G.,University of Toronto | Saposnik G.,Institute of Clinical Evaluative science
Journal of Stroke and Cerebrovascular Diseases | Year: 2013

Bilateral infarction of the medial medulla (MMI) is rare. Limited information is available on clinical characteristics, etiology, and prognosis. High-resolution neuroimaging has a major role in elucidating the underlying stroke mechanism. The aim of this systematic review was to analyze the clinical presentations, stroke mechanisms, and outcomes in patients with bilateral MMI. We performed a systematic review of the literature from 1992-2011 that reported on clinical presentations, stroke mechanism, and/or outcomes in patients with magnetic resonance imaging-proven bilateral MMI. Medline, EMBASE, and Web of Science Scholars Portal were searched without language restriction. Two reviewers independently assessed identified studies to determine eligibility, validity, and quality. The primary outcome was inpatient mortality; a secondary outcome was case fatality at 12 months. We identified 138 articles from Medline, EMBASE, and Scholars Portal including the MeSH terms "brainstem infarction," "medulla," and "bilateral." Twenty-nine articles met our inclusion criteria, including a total of 38 cases with bilateral MMI, and included in our study. These 38 patients had a mean age of 62.2 years and were predominately male (74.2%). The most common clinical presentations were motor weakness in 78.4%, dysarthria in 48.6%, and hypoglossal palsy in 40.5%. The most common vascular pathology was vertebral artery atherosclerosis, in 38.5%. The clinical outcome was poor (mortality, 23.8%; dependency, 61.9%). Bilateral medial medullary infarction is a rare stroke syndrome. Clinical presentations were mostly rostral medullary lesions. Large-artery atherosclerosis and branch disease were the most common stroke mechanisms. The clinical outcome was usually poor. © 2013 by National Stroke Association.


Edjoc R.K.,Ottawa Hospital Research Institute | Reid R.D.,University of Ottawa | Sharma M.,McMaster University | Fang J.,Institute of Clinical Evaluative science
Journal of Stroke and Cerebrovascular Diseases | Year: 2013

Objective: The aim of this study was to determine the prognostic influence of cigarette smoking on stroke severity, disability, length of stay (LOS) in hospital, and mortality in different stroke types. Methods: A cohort separated by smoking status from the Registry of the Canadian Stroke Network was analyzed using logistic regression while controlling for key outcomes and clinical and demographic characteristics. Results: There were 20,523 patients that were included for this study from July 2003 to March 2008. Multivariable analyses revealed that, in general, long-time smoking had a negative effect on functional outcome at discharge, mortality at 1 year, and LOS in hospital. In general, former smoking had a positive impact in reducing the risk of severe stroke, mortality risk at 30 days, and the LOS in hospital. Significant differences in clinical and demographics were found between smokers, nonsmokers, and former smokers with cerebrovascular disease. On average, smokers had an earlier initial stroke presentation of cerebrovascular disease. Conclusions: Our results provide empirical evidence regarding the prognostic influence of cigarette smoking on stroke severity, disability, and LOS in hospital and mortality, but the magnitude of the effect varied by stroke type. © 2013 Elsevier B.V. All rights reserved.


Seow H.-Y.,McMaster University | Sibley L.M.,Institute of Clinical Evaluative science
BMC Health Services Research | Year: 2014

Results: We identified 11.4 million adults. 16.1% were aged 65 or older, 3.2 million (28%) did not use health care services that year, and 45,000 (0.4%) were in the highest acuity ACG category using 12 times more than an average adult. The sickest 1%, 5% and 15% of the population use about 10%, 30% and 50% of total health system costs respectively. The dashboard measures 2 dimensions of Triple Aim: 1) reduced costs: when total system costs per ACG or when average costs per person is reduced; and 2) improved population health: when more people move into healthier rather than sicker ACGs. It can help to achieve the third aim, improved care experience, when ACG utilization predictions are reported to providers to proactively develop care plans.Conclusions: The dashboard, developed via case-mix methods, measures 2 of the Triple Aim goals and can help health system planners better manage their health delivery systems. © 2014 Seow and Sibley; licensee BioMed Central Ltd.Methods: We applied a case-mix adjustment method to a population-based analysis to assess its usefulness as a measure of health system performance and Triple Aim. The study design was a retrospective, cohort study of adults from Ontario, Canada using administrative databases: individuals were assigned a predicted illness burden score using a case-mix adjustment system from diagnoses and health utilization data in 2008, and then followed forward to assess the actual health care utilization and costs in the following year (2009). We applied the Johns Hopkins Adjusted Clinical Group (ACG) Case-Mix System to categorize individuals into 60 levels of healthcare need, called ACGs. The outcomes were: 1) Number of individuals per ACG; 2) Total system costs per ACG; and 3) Mean cost per person per ACG, which together formed a health system "dashboard".Background: Health system planners aim to pursue the three goals of Triple Aim: 1) reduce health care costs; 2) improve population health; and 3) improve the care experience. Moreover, they also need measures that can reliably predict future health care needs in order to manage effectively the health system performance. Yet few measures exist to assess Triple Aim and predict future needs at a health system level. The purpose of this study is to explore the novel application of a case-mix adjustment method in order to measure and help improve the Triple Aim of health system performance.


Henry D.A.,Institute of Clinical Evaluative science
Cochrane database of systematic reviews (Online) | Year: 2011

Concerns regarding the safety of transfused blood have led to the development of a range of interventions to minimise blood loss during major surgery. Anti-fibrinolytic drugs are widely used, particularly in cardiac surgery, and previous reviews have found them to be effective in reducing blood loss, the need for transfusion, and the need for re-operation due to continued or recurrent bleeding. In the last few years questions have been raised regarding the comparative performance of the drugs. The safety of the most popular agent, aprotinin, has been challenged, and it was withdrawn from world markets in May 2008 because of concerns that it increased the risk of cardiovascular complications and death. To assess the comparative effects of the anti-fibrinolytic drugs aprotinin, tranexamic acid (TXA), and epsilon aminocaproic acid (EACA) on blood loss during surgery, the need for red blood cell (RBC) transfusion, and adverse events, particularly vascular occlusion, renal dysfunction, and death. We searched: the Cochrane Injuries Group's Specialised Register (July 2010), Cochrane Central Register of Controlled Trials (The Cochrane Library 2010, Issue 3), MEDLINE (Ovid SP) 1950 to July 2010, EMBASE (Ovid SP) 1980 to July 2010. References in identified trials and review articles were checked and trial authors were contacted to identify any additional studies. The searches were last updated in July 2010. Randomised controlled trials (RCTs) of anti-fibrinolytic drugs in adults scheduled for non-urgent surgery. Eligible trials compared anti-fibrinolytic drugs with placebo (or no treatment), or with each other. Two authors independently assessed trial quality and extracted data. This review summarises data from 252 RCTs that recruited over 25,000 participants. Data from the head-to-head trials suggest an advantage of aprotinin over the lysine analogues TXA and EACA in terms of reducing perioperative blood loss, but the differences were small. Compared to control, aprotinin reduced the probability of requiring RBC transfusion by a relative 34% (relative risk [RR] 0.66, 95% confidence interval [CI] 0.60 to 0.72). The RR for RBC transfusion with TXA was 0.61 (95% CI 0.53 to 0.70) and was 0.81 (95% CI 0.67 to 0.99) with EACA. When the pooled estimates from the head-to-head trials of the two lysine analogues were combined and compared to aprotinin alone, aprotinin appeared more effective in reducing the need for RBC transfusion (RR 0.90; 95% CI 0.81 to 0.99).Aprotinin reduced the need for re-operation due to bleeding by a relative 54% (RR 0.46, 95% CI 0.34 to 0.62). This translates into an absolute risk reduction of 2% and a number needed-to-treat (NNT) of 50 (95% CI 33 to 100). A similar trend was seen with EACA (RR 0.32, 95% CI 0.11 to 0.99) but not TXA (RR 0.80, 95% CI 0.55 to 1.17). The blood transfusion data were heterogeneous and funnel plots indicate that trials of aprotinin and the lysine analogues may be subject to publication bias.When compared with no treatment aprotinin did not increase the risk of myocardial infarction (RR 0.87, 95% CI 0.69 to 1.11), stroke (RR 0.82, 95% CI 0.44 to 1.52), renal dysfunction (RR 1.10, 95% CI 0.79 to 1.54) or overall mortality (RR 0.81, 95% CI 0.63 to 1.06). Similar trends were seen with the lysine analogues, but data were sparse. These data conflict with the results of recently published non-randomised studies, which found increased risk of cardiovascular complications and death with aprotinin. There are concerns about the adequacy of reporting of uncommon events in the small clinical trials included in this review.When aprotinin was compared directly with either, or both, of the two lysine analogues it resulted in a significant increase in the risk of death (RR 1.39, 95% CI 1.02, 1.89), and a non-significant increase in the risk of myocardial infarction (RR 1.11 95% CI 0.82, 1.50). Most of the data contributing to this added risk came from a single study - the BART trial (2008). Anti-fibrinolytic drugs provide worthwhile reductions in blood loss and the receipt of allogeneic red cell transfusion. Aprotinin appears to be slightly more effective than the lysine analogues in reducing blood loss and the receipt of blood transfusion. However, head to head comparisons show a lower risk of death with lysine analogues when compared with aprotinin. The lysine analogues are effective in reducing blood loss during and after surgery, and appear to be free of serious adverse effects.

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