Clinical characteristics, angiographic findings, and one-year outcome of 101 consecutive stent thrombosis cases in British Columbia.

BACKGROUND: Stent thrombosis (ST) is rare, but is associated with significant morbidity and mortality. METHODS: We analyzed data from the British Columbia (BC) Registry from April 2011-January 2012. RESULTS: 101 ST cases were reported and verified. Based on timing, ST was considered early (≤30days) in 35.6%, late (>30days-1year) in 17.8% and very late (>1year) in 46.5%. The majority (68.5%) presented with STEMI, and the remaining with non-STEMI (31.5%). Most vessels were functionally occluded (TIM1 flow grade ≤1 in 67.1%). Thrombus burden was high (TIMI thrombus grade ≥4 in 77.2%). Aspiration thrombectomy was performed in 41% of cases. New stents were implanted in 62.4% cases. Intra-coronary imaging was low (11%). At the original stent implantation, STEMI was the clinical presentation in 39.6%, the lesion was complex in 62.1%, and thrombus was visualized in 23.0%. Prognosis after ST was unfavorable with high mortality (11.9% at 30days and 16.8% at one year), and further revascularization (5.0% repeat PCI and 6.9% coronary artery bypass graft surgery). Early ST was associated with worse clinical outcome compared to late/very late ST: 30-day mortality at 22.2% versus 6.2% (p=0.02), and 1-year mortality at 27.8% versus 10.8% (p=0.05). CONCLUSIONS: In this prospective registry from BC, all ST presented with myocardial infarction, and the majority was treated with emergency PCI. Additional stents were commonly implanted with infrequent use of intracoronary imaging. Mortality rate was higher for early ST in comparison with late/very late ST. A comprehensive approach should be developed to treat this difficult complication.

Thinking about aboriginal KT: learning from the Network Environments for Aboriginal Health Research British Columbia (NEARBC).

OBJECTIVE: Creating effective and actionable research has become increasingly important for the health disciplines. Despite greater attention to knowledge translation (KT) in the health research, policy, and professional literature and the mounting need for strategic action to reduce the burden of ill health experienced by Aboriginal people in Canada, little time has been dedicated to understanding KT in Aboriginal health research contexts (Aboriginal KT). The purpose of this study was to explore and discuss the unique qualities of Aboriginal KT. METHODS: An exploratory case study of the Network Environments for Aboriginal Research British Columbia (NEARBC) was undertaken, in which qualitative interviewing with experts associated with the network was conducted. RESULTS: Four themes were revealed from the analysis of 10 semi-structured qualitative interviews: 1) Definitional debate, 2) "Aboriginal" KT, 3) Doing KT, and 4) KT roles. These themes highlight the definitional complexity, practical confusion, multidisciplinary nature, and lack of accountability related to Aboriginal KT. DISCUSSION: The information gained from the study participants adds some important insights to the current literature. It also identifies areas where future discussion may help improve the understanding and meaning of KT in Aboriginal health research contexts, as well as its application in practice. The health disparities of Aboriginal people in Canada are a call for action with regards to KT and this study provides some basic information and advice on ways to move the research and policy agenda forward.

Disparities in chronic disease among Canada's low-income populations.

INTRODUCTION: Many studies have found inequities in health among income groups in Canada. We report the variations in the major chronic disease risks among low-income populations, by province of residence, as a proxy measure of social environment. METHODS: We used estimates from the 2005 Canadian Community Health Survey to study residents who were aged 45 years or older and from the lowest income quintile nationally. Multivariate logistic regression was used to examine the relationship between province of residence and risk of chronic diseases. RESULTS: British Columbia is the healthiest province overall but not in terms of its low-income residents, whereas Quebec's low-income residents are at the least risk for major chronic diseases. The significant differences in risk of hypertension, diabetes, and heart disease in favor of British Columbia over Quebec for the entire population disappear when considering only the low-income subset. CONCLUSION: Quebec's antipoverty strategy, formalized as law in 2002, has led to social and health care policies that appear to give its low-income residents advantages in chronic disease prevention. Our findings demonstrate that chronic disease prevalence is associated with investment in social supports to vulnerable populations.

Taking a life course perspective on cardiovascular disease and diabetes in First Nations peoples.

The burden of cardiovascular disease and diabetes and associated risk factors, such as obesity, smoking, impaired glucose tolerance, hypertension, and dietary factors, present a mix of factors that are detrimental to the immediate and long-term health of First Nations peoples in Canada. The authors use a life course perspective to examine the long-term effects of risk factors that are prevalent during gestation, childhood, adolescence, young adulthood, and adult life on developmental health and later disease risk. The resultant broader perspective may generate innovative approaches to addressing chronic disease in Canada's Aboriginal population.

Knowledge translation in the context of Aboriginal health.

Interest in the concept of knowledge translation (KT), one of the many terms used to describe the process(es) through which knowledge is transformed into action, is increasingly prevalent in the mainstream health literature. Despite a pressing need, little has been done to address the implications of evolving theories and strategies for KT in an Aboriginal context. The authors attempt to narrow the gap by reviewing the literature on Aboriginal KT and exploring ways to extend this work by engaging with the Aboriginal health research literature and the KT literature. They argue that the inclusion of multiple perspectives and an examination of the social and political context in which Aboriginal KT takes shape are important for the conceptual development of Aboriginal KT. This article is particularly relevant for those involved at the interface between nursing practice and efforts to improve Aboriginal health.

A KCNQ1 V205M missense mutation causes a high rate of long QT syndrome in a First Nations community of northern British Columbia: a community-based approach to understanding the impact.

PURPOSE: Hereditary long QT syndrome is named for a prolonged QT interval reflecting predisposition to ventricular arrhythmias and sudden death. A high rate in a remote, northern Canadian First Nations community was brought to attention. METHODS: Two severely affected index cases and 122 relatives were ascertained using community-based participatory research principles. Genetic sequencing of five known genes responsible for long QT syndrome was carried out on the index cases, leading to the identification of a novel missense mutation. Functional properties of the identified mutation were studied in transfected mouse ltk- cells using whole cell patch clamp techniques. Corrected QT interval measurements were obtained from participants and subsequent genotyping of relatives was carried out. RESULTS: In the two index cases, a novel missense mutation (V205M) was identified in the S3 transmembrane helix of KvLQT1, the pore forming domain of the IKs channel complex. In transfected mouse ltk-cells the V205M mutation suppressed IKs by causing a dramatic depolarizing shift in activation voltage coupled with acceleration of channel deactivation. Twenty-two mutation carriers had a significantly higher mean corrected QT interval than noncarriers (465 +/- 28 milliseconds vs. 434 +/- 26 milliseconds, P < 0.0001); however, 30% of carriers had a corrected QT interval below 440 milliseconds. CONCLUSION: A novel KCNQ1 mutation in this founder population likely confers increased susceptibility to arrhythmias because of decreased IKs current. Even with a common mutation within a relatively homogenous population, clinical expression remains variable, exemplifying the multifactorial nature of long QT syndrome, and supporting the difficulty of definitive diagnosis without genetic testing. A community participatory approach enabled a comprehensive evaluation of the impact.

Innovative approaches in public health research: applying life course epidemiology to aboriginal health research.

A life course epidemiology approach embraces the complexity of disease risk and acknowledges the long-term effects of physical, social, psychological, and behaviour pathways, operating across an individual's life, a community's generation, and a population's development, on health and well-being. Researchers who adopt a life course epidemiology approach broaden their ability to understand, explain, and prescribe ways to mitigate the effects of chronic diseases and reduce risk factor development and interaction. Although there are many diseases that explicate the importance and usefulness of a life course approach for Aboriginal health research, this commentary focuses on the benefits for understanding chronic respiratory diseases in Aboriginal populations. The hope is that this will expose the benefits of a life course approach for the study of Aboriginal health research and draw attention to the need for well-rounded, high-quality Aboriginal respiratory health research.

An innovative application of Bayesian disease mapping methods to patient safety research: a Canadian adverse medical event study.

Recently developed disease mapping and ecological regression methods have become important techniques in studies of disease epidemiology and in health services research. This increase in importance is partially a result of the development of Bayesian statistical methodologies that make it possible to study associations between health problems and risk factors at an aggregate (i.e. areal) level while taking into account such matters as unmeasured confounding and spatial relationships. In this paper we present a demonstration of the joint use of empirical Bayes (EB) and full Bayesian inferential techniques in a small area study of adverse medical events (also known as 'iatrogenic injury') in British Columbia, Canada. In particular, we illustrate a unified Bayesian hierarchical spatial modelling framework that enables simultaneous examinations of potential associations between adverse medical event occurrence and regional characteristics, age effects, residual variation and spatial autocorrelation. We propose an analytic strategy for complementary use of EB and FB inferential techniques for risk assessment and model selection, presenting an EB-FB combined approach that draws on the strengths of each method while minimizing inherent weaknesses. The work was motivated by the need to explore relatively efficient ways to analyse regional variations of health services outcomes and resource utilization when a considerable amount of statistical modelling and inference are required.

Transfusion rates vary significantly amongst Canadian medical centres.

PURPOSE: To document variation of transfusion practice following repair of hip fracture or cardiac surgery, as well as those requiring intensive care following a surgical intervention or multiple trauma (high risk patients). METHODS: We documented rates of allogeneic red cell transfusion in 41,568 patients admitted to 11 hospitals across Canada between August 1998 and August 2000 as part of a retrospective observational cohort study. In the subgroup of 7,552 patients receiving red cells, we also compared mean nadir hemoglobin concentrations from centre to centre. RESULTS: The overall rate of red cell transfusion was 38.7%, and ranged from 23.8% to 51.9% across centres among the 41,568 perioperative and critically ill patients. Women were more likely to be transfused (43.7% vs 35.3%, P < 0.0001), with higher rates of transfusion in eight of 11 centres. Compared to a chosen reference hospital having a crude transfusion rate near the median, the adjusted odds of transfusion ranged from 0.44 to 1.53 overall, from 0.42 to 1.22 in patients undergoing a hip fracture repair, from 0.72 to 3.17 in cardiac surgical patients undergoing cardiac surgery, and from 0.27 to 1.11 in critically ill and trauma patients. In the 7,552 transfused patients, the mean adjusted nadir hemoglobin was 74.0 +/- 4.83 g x L(-1) overall, and ranged from 66.9 +/- 1.7 g x L(-1) to 84.5 +/- 1.6 g x L(-1) across centres. Similar differences among centres were observed amongst hip fracture patients (71.2 +/- 2.9 g x L(-1) to 82.8 +/- 1.7 g x L(-1)), cardiac surgical patients (65.7 +/- 1.1 g x L(-1) to 77.3 +/- 1.0 g x L(-1)) and critically ill and trauma patients (66.1 +/- 3.04 g x L(-1) to 87.5 +/- 2.5 g x L(-1)). CONCLUSION: We noted significant differences in the rates of red cell transfusion and nadir hemoglobin concentrations in various surgical and critical care settings.

Clinical outcomes following institution of the Canadian universal leukoreduction program for red blood cell transfusions.

CONTEXT: A number of countries have implemented a policy of universal leukoreduction of their blood supply, but the potential role of leukoreduction in decreasing postoperative mortality and infection is unclear. OBJECTIVE: To evaluate clinical outcomes following adoption of a national universal prestorage leukoreduction program for blood transfusions. DESIGN, SETTING, AND POPULATION: Retrospective before-and-after cohort study conducted from August 1998 to August 2000 in 23 academic and community hospitals throughout Canada, enrolling 14 786 patients who received red blood cell transfusions following cardiac surgery or repair of hip fracture, or who required intensive care following a surgical intervention or multiple trauma. INTERVENTION: Universal prestorage leukoreduction program introduced by 2 Canadian blood agencies. A total of 6982 patients were enrolled during the control period and 7804 patients were enrolled following prestorage leukoreduction. MAIN OUTCOME MEASURES: All-cause in-hospital mortality and serious nosocomial infections (pneumonia, bacteremia, septic shock, all surgical site infections) occurring after first transfusion and at least 2 days after index procedure or intensive care unit admission. Secondary outcomes included rates of posttransfusion fever and antibiotic use. RESULTS: Unadjusted in-hospital mortality rates were significantly lower following the introduction of leukoreduction compared with the control period (6.19% vs 7.03%, respectively; P =.04). Compared with the control period, the adjusted odds of death following leukoreduction were reduced (odds ratio [OR], 0.87; 95% confidence interval [CI], 0.75-0.99), but serious nosocomial infections did not decrease (adjusted OR, 0.97; 95% CI, 0.87-1.09). The frequency of posttransfusion fevers decreased significantly following leukoreduction (adjusted OR, 0.86; 95% CI, 0.79-0.94), as did antibiotic use (adjusted OR, 0.90; 95% CI, 0.82-0.99). CONCLUSION: A national universal leukoreduction program is potentially associated with decreased mortality as well as decreased fever episodes and antibiotic use after red blood cell transfusion in high-risk patients.

Multiple imputation to account for missing data in a survey: estimating the prevalence of osteoporosis.

BACKGROUND: Nonresponse bias is a concern in any epidemiologic survey in which a subset of selected individuals declines to participate. METHODS: We reviewed multiple imputation, a widely applicable and easy to implement Bayesian methodology to adjust for nonresponse bias. To illustrate the method, we used data from the Canadian Multicentre Osteoporosis Study, a large cohort study of 9423 randomly selected Canadians, designed in part to estimate the prevalence of osteoporosis. Although subjects were randomly selected, only 42% of individuals who were contacted agreed to participate fully in the study. The study design included a brief questionnaire for those invitees who declined further participation in order to collect information on the major risk factors for osteoporosis. These risk factors (which included age, sex, previous fractures, family history of osteoporosis, and current smoking status) were then used to estimate the missing osteoporosis status for nonparticipants using multiple imputation. Both ignorable and nonignorable imputation models are considered. RESULTS: Our results suggest that selection bias in the study is of concern, but only slightly, in very elderly (age 80+ years), both women and men. CONCLUSIONS: Epidemiologists should consider using multiple imputation more often than is current practice.