Institute For Clinical Evaluative Sciences Research Articles

Ecological Studies and Cardiovascular Outcomes Research

Is it better to have a heart attack in the United States or Canada? Ecological studies are epidemiological evaluations in which the unit of analysis is populations, or groups of people, rather than individuals.1 They can answer important questions such as the question posed above that cannot easily be answered using any other form of study design. Ecological studies are conducted by researchers in a variety of disciplines, including outcomes researchers, to study potential causal associations between 1 or more exposure and outcome variables. They are frequently used where alternative study designs are not possible (eg, randomized control trials), such as when investigating the effect of geographical and temporal factors on disease incidence or the effect of a government policy change on health outcomes. In this overview, we provide an introduction to the use of ecological studies in cardiovascular outcomes research, drawing on published examples from our group and others. It is important for clinicians to be aware of both the potential strengths and weaknesses of this type of study design. Because ecological studies are ubiquitous in the medical literature, it is not possible to review all published cardiovascular ecological studies in a systematic manner. Individual-level variables are properties of each person whereas ecological variables are properties of groups, organizations, or places.1,2 All ecological studies are potentially prone to the so-called “ecological fallacy,” which is a term for the biases that may occur when the association that exists between variables at an aggregate level may not represent the true association that exists at an individual level.3 On the other hand, the ecological fallacy may be offset by avoidance of the “individualistic fallacy” whereby one assumes that individual patients are unaffected by the neighborhood in which they live or the setting in which they are treated.4 Complete …

Stroke Prevention and Sodium Restriction

Stroke prevention is extremely cost-effective. The Ontario Task Force for the Coordinated Stroke Strategy for Ontario received from Dr. Muhammad Mamdani of the Institute for Clinical Evaluative Sciences the estimate that stroke prevention is approximately ten times more cost-effective than treating acute stroke with tPA.1 Hackam and Spence2 have calculated that in the highest-risk patients it would be possible to reduce the risk of stroke by more than 90% by a combination of interventions (including blood pressure control, smoking cessation, diet, treatment of diabetes, lipid-lowering therapy, and for patients in whom it is indicated, anticoagulation for atrial fibrillation or carotid endarterectomy). Dr Mukul Sharma (personal communication) has shown that stroke prevention is a dominant strategy in health economic terms; i.e. that it improves outcomes while reducing net costs. Effective control of hypertension has the potential to reduce stroke by half.3,4 Because hypertension is so prevalent, it accounts for the greatest population attributable risk for stroke, and thus represents the greatest opportunity to reduce stroke.

ICES Report: Do Ontario Patients with Heart Failure Have Equal Access to Life-Saving Technology?

Sudden cardiac death (SCD) is a major cause of mortality, and many such events are due to lethal heart rhythm disturbances or ventricular arrhythmias. Patients with a prior heart attack and left ventricular dysfunction are at particularly high risk of SCD. Although the majority of drug therapies have been ineffective in preventing sudden cardiac death, the implantable cardioverter defibrillator (ICD) – a device similar in size to a pacemaker that allows for heart monitoring and immediate cardiac shock if necessary – has been found to significantly reduce the chance of mortality and arrhythmic death in those at increased risk of cardiac events. Randomized trials of the ICD found that it substantially improved outcome in cardiac arrest survivors. The ICD was also found to offer significant survival benefits when used for primary prevention (i.e., in heart failure patients with no history of a cardiac arrest). The recommendations for ICDs were, therefore broadened to include those who have never had a cardiac arrest, but had reduced cardiac pump function and prior heart attack or heart failure. However, there may be disparities in access to this technology because of its novelty and high cost (approximately $30,000 per device). To better explore possible inequities in the use of implantable defibrillators in a universal healthcare environment, scientists at the Institute for Clinical Evaluative Sciences (ICES) examined the use of such procedures for the primary prevention of sudden cardiac death in Ontario from 1993 to 2004. The Study Using the Canadian Institute for Health Information Discharge

Testing a TheoRY-inspired MEssage ('TRY-ME'): a sub-trial within the Ontario Printed Educational Message (OPEM) trial

BackgroundA challenge for implementation researchers is to develop principles that could generate testable hypotheses that apply across a range of clinical contexts, thus leading to generalisability of findings. Such principles may be provided by systematically developed theories. The opportunity has arisen to test some of these theoretical principles in the Ontario Printed Educational Materials (OPEM) trial by conducting a sub-trial within the existing trial structure. OPEM is a large factorial cluster-randomised trial evaluating the effects of short directive and long discursive educational messages embedded into informed, an evidence-based newsletter produced in Canada by the Institute for Clinical Evaluative Sciences (ICES) and mailed to all primary care physicians in Ontario. The content of educational messages in the sub-trial will be constructed using both standard methods and methods inspired by psychological theory. The aim of this study is to test the effectiveness of the TheoRY-inspired MEssage ('TRY-ME') compared with the 'standard' message in changing prescribing behaviour.MethodsThe OPEM trial participants randomised to receive the short directive message attached to the outside of informed (an 'outsert') will be sub-randomised to receive either a standard message or a message informed by the theory of planned behaviour (TPB) using a two (long insert or no insert) by three (theory-based outsert or standard outsert or no outsert) design. The messages will relate to prescription of thiazide diuretics as first line drug treatment for hypertension (described in the accompanying protocol, "The Ontario Printed Educational Materials trial"). The short messages will be developed independently by two research teams.The primary outcome is prescription of thiazide diuretics, measured by routinely collected data available within ICES. The study is designed to answer the question, is there any difference in guideline adherence (i.e., thiazide prescription rates) between physicians in the six groups? A process evaluation survey instrument based on the TPB will be administered pre- and post-intervention (described in the accompanying protocol, "Looking inside the black box"). The second research question concerns processes that may underlie observed differences in prescribing behaviour. We expect that effects of the messages on prescribing behaviour will be mediated through changes in physicians' cognitions.Trial registration numberCurrent controlled trial ISRCTN72772651

The Ontario printed educational message (OPEM) trial to narrow the evidence-practice gap with respect to prescribing practices of general and family physicians: a cluster randomized controlled trial, targeting the care of individuals with diabetes and hypertension in Ontario, Canada

BackgroundThere are gaps between what family practitioners do in clinical practice and the evidence-based ideal. The most commonly used strategy to narrow these gaps is the printed educational message (PEM); however, the attributes of successful printed educational messages and their overall effectiveness in changing physician practice are not clear. The current endeavor aims to determine whether such messages change prescribing quality in primary care practice, and whether these effects differ with the format of the message.Methods/designThe design is a large, simple, factorial, unblinded cluster-randomized controlled trial. PEMs will be distributed with informed, a quarterly evidence-based synopsis of current clinical information produced by the Institute for Clinical Evaluative Sciences, Toronto, Canada, and will be sent to all eligible general and family practitioners in Ontario. There will be three replicates of the trial, with three different educational messages, each aimed at narrowing a specific evidence-practice gap as follows: 1) angiotensin-converting enzyme inhibitors, hypertension treatment, and cholesterol lowering agents for diabetes; 2) retinal screening for diabetes; and 3) diuretics for hypertension.For each of the three replicates there will be three intervention groups. The first group will receive informed with an attached postcard-sized, short, directive "outsert." The second intervention group will receive informed with a two-page explanatory "insert" on the same topic. The third intervention group will receive informed, with both the above-mentioned outsert and insert. The control group will receive informed only, without either an outsert or insert.Routinely collected physician billing, prescription, and hospital data found in Ontario's administrative databases will be used to monitor pre-defined prescribing changes relevant and specific to each replicate, following delivery of the educational messages. Multi-level modeling will be used to study patterns in physician-prescribing quality over four quarters, before and after each of the three interventions. Subgroup analyses will be performed to assess the association between the characteristics of the physician's place of practice and target behaviours.A further analysis of the immediate and delayed impacts of the PEMs will be performed using time-series analysis and interventional, auto-regressive, integrated moving average modeling.Trial registration numberCurrent controlled trial ISRCTN72772651.

Written on the Landscape: Health and Region in Canada

Canada's health-care system is a cornerstone of the welfare state and, equally, a cornerstone in the country's national identity. Whether discussing access to services, the politics of providing particular kinds of services such as abortion, the distribution of health-care providers, the and treatment of chronic disease, or new global threats to health such as SARS, few topics stir the passions of Canadians like health care. Recent reports such as Revitalizing Medicare (Rachlis et al. 2001) and the Romanow report (Commission on the Future of Health Care 2002) suggest many strategies for sustaining and reforming health and, while they differ in their orientation and approach, both affirm Canadians' affection for Medicare. It is, however, equally important to acknowledge that this affection is the product of an imagined Medicare, one that emphasizes a story of access and equity. To use Michael Bliss's phrase, this imagined Medicare is the result of a brief but very important golden age of Canadian medicare (2002, 38). This golden age emerged from the reconstruction of health from the early 1950s to the early 1970s, took many forms including the implementation of the national health grants, the passage of the federal Hospital Insurance and Diagnostic Services Act (1957), and legislation for physicians' services (1966); but a complete analysis must address how this golden age quickly evaporated in the face of mounting costs and regional disparities. Indeed, the Romanow report itself highlighted major regional discrepancies in the quality of health care. The idea that place matters for health services and health outcomes is not a particularly novel notion. In introducing the inaugural issue of the journal Health and Place, editor Graham Moon wrote that the journal sought to publish research which contributes to an understanding of how, why and whether place and context really matter when it comes to health and health care (1995, 1). Canada, it would seem, provides a veritable laboratory through one can explore this question. In a general sense, the health-care system provides comprehensive coverage for inpatient, hospital-based services and for outpatient physician services. Among the early civics lessons Canadians learn are the divisions of power under the Constitution Act, places health (with some important exceptions, such as responsibility for Aboriginal health) firmly under provincial jurisdiction. Each of the provinces and territories is responsible for managing and delivering health services within its jurisdiction. The focus on federal or provincial responsibilities, however, obscures the fact that much of the real activity of health takes place in an even more local setting, in the town or municipality or, more recently, in the health regions that were established in most jurisdictions during the administrative reorganization of the 1990s. It is perhaps not surprising, then, that health services are uneven across Canada and health outcomes can vary tremendously from setting to setting, even for the same procedures. There is, for example, abundant evidence that a woman's chance of having a caesarian section is higher in some facilities, while similar women in other facilities may avoid the procedure (Anderson and Lomas 1985). Data from 2001-2002 demonstrate that primary caesarian section rates ranged from a low of 12.4% in Manitoba to 21% in Prince Edward Island. Provincial statistics obscure even higher variations: in the Region 6 Health Corporation in New Brunswick (centred on Bathurst), primary caesarian section rates reached 25.5% (CIHI 2004). Since 1994, the Institute for Clinical Evaluative Sciences (ICES), based at the University of Toronto, has generated a great deal of publicity, raised the ire of some hospitals, and prompted critiques from different quarters, through their clinical atlas initiatives and report cards on various clinical services. The institute's objective was to collect and analyze data on a variety of performance measures, paying particular attention to individual institutions and geographic setting. …

The Transition to Adulthood for Children With Cerebral Palsy

From the Laurentian University, Sudbury, Ontario; The Hospital for Sick Children, Toronto, Ontario; and The Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada.

Poststroke Care

See related article, pages 1899–1904. “Thinking is easy, acting is difficult, and to put one’s thoughts into action is the most difficult thing in the world”. — —Goethe (1749–1832) Major advances in acute stroke management have been seen over the past decade, including the use of thrombolysis, antithrombotic therapy, and organized in-hospital stroke care. However, relatively few studies have evaluated the effectiveness of these interventions in routine clinical practice, or have assessed issues related to delivery of services, access to care, and long-term care after discharge from stroke. In this issue of Stroke , Bravata et al1 contribute to our understanding of outcomes after stroke by analyzing readmissions and deaths in the first 5 years after a hospitalization for stroke. The target population included stroke survivors aged over 65 years who were Medicare beneficiaries and who were discharged from Connecticut acute care hospitals in 1995. This population was followed from discharge in 1995 through 2000 using Medicare claims and Social Security Administration mortality data. Among 2603 patients discharged alive, 40% were readmitted at least once within the first year of discharge, 53% had died or been readmitted within 1 year and only 15% survived admission-free for 5 years. Leading causes for readmission included pneumonia (8.2% to 9.0%), stroke (3.9% to 6.1%) and acute myocardial infarction (4.2% to 6.0%). There was no apparent association between length of hospital stay and readmission rate (unreported data kindly provided by the authors, 2007), and no information was available on potential patient and system factors associated with higher hospital readmission rates. Lower readmission rates of 25% to 27% within 1 year have been previously reported.2,3 These studies found that the average number of days of rehospitalization was 23.2 Stroke was the single most frequent reason for readmission followed by cardiac disease, …

ICES Report: The Growing Prevalence of Diabetes in Ontario: Are We Prepared?

The Issue The number of persons with diabetes worldwide has increased dramatically over the past 20 years, making it one of the most burdensome diseases of our time. It is one of the leading causes of blindness and end-stage renal disease, and an important cause of cardiovascular complications. Furthermore, the treatment is complex and costly, with the direct healthcare costs of diabetes ranging from 2.5 to 15% of health budgets. Rates of diabetes are expected to continue to increase over time. The World Health Organization (WHO) predicted that the global diabetes prevalence rate among adults would reach 6.4% by 2030, representing a 60% increase since 1995 and a 39% rise from 2000. However, these projections may be underestimates as they were based on an unwarranted assumption that obesity rates would remain constant. In a recent study, scientists at Ontario’s Institute for Clinical Evaluative Sciences (ICES) described trends in diabetes prevalence, incidence and mortality in Ontario, from 1994/95 (April 1, 1994 to March 31, 1995) to 2004/05 (April 1, 2004 to March 31, 2005). The Growing Prevalence of Diabetes in Ontario: Are We Prepared?

Factors Associated With Incomplete Colonoscopy: A Population-Based Study

The U.S. Multi-Society Task Force on Colorectal Cancer sets a target of cecal intubation in at least 90% of colonoscopies. We conducted a population-based study to determine the colonoscopy completion rate and to identify factors associated with incomplete procedures. Men and women 50 to 74 years of age who underwent a colonoscopy in Ontario between January 1, 1999, and December 31, 2003, were identified. The first (index) colonoscopy was classified as complete or incomplete. A generalized estimating equations model was used to evaluate the association between patient, endoscopist (specialty, colonoscopy volume), and setting (academic hospital, community hospital, private office) factors and incomplete colonoscopy. A total of 331,608 individuals had an index colonoscopy, of which 43,483 (13.1%) were incomplete. Patients with an incomplete colonoscopy were older (odds ratio [OR] 1.20 per 10-year increment; 95% confidence interval [CI]=1.18-1.22), more likely to be female (OR 1.35; 95% CI: 1.30-1.39), have a history of prior abdominal surgery (OR 1.07; 95% CI: 1.05-1.09) or prior pelvic surgery (OR 1.04; 95% CI: 1.01-1.06). For colonoscopies done in a private office, the odds of an incomplete procedure were more than 3-fold greater than for procedures done in an academic hospital (OR 3.57; 95% CI: 2.55-4.98). In usual clinical practice in Ontario, 13.1% of colonoscopies are incomplete. The factors most strongly associated with incomplete colonoscopy were increased patient age, female sex, and having the procedure in a private office. Quality improvement programs are needed to improve colonoscopy completion rates.

Colorectal Cancer Screening: Opportunistic or Organized?

Colorectal Cancer Screening: Opportunistic or Organized?

Using Technology to Reduce Adverse Drug Events in Elderly Long-Term Care Patients: The Case for Computerized Physician Order Entry

Jennifer L Gold1 & Paula A Rochon2† †Author for correspondence 1University of Toronto, Kunin-Lunenfeld Applied Research Unit, Baycrest Centre for Geriatric Care, Faculty of Law, Canada. 2University of Toronto, Institute for Clinical Evaluative Sciences, Sunnybrook & Women’s College Health Sciences Centre, Department of Health Policy, Management and Evaluation, Kunin-Lunenfeld Applied Research Unit Baycrest Centre for Geriatric Care, 3560 Bathurst Street, Toronto M6A 2E1, Canada. Tel.: +1 416 785 2500 ext. 2516; Fax: +1 416 785 4230; E-mail: paula.rochon@ utoronto.ca

The growing volume of diabetes-related dialysis: a population based study

End-stage renal failure requiring dialysis is one of the most serious complications of diabetes mellitus, and diabetes is the most common cause of end-stage renal failure. The aim of this large, observational study is to describe the population-based incidence and prevalence rates and outcomes of diabetic individuals in Ontario, Canada who require dialysis therapy. Two cohorts of patients, those with diabetes and those without, were created between April 1, 1994 and March 31, 2000 (total of approximately 8.4 million) and followed until March 31, 2001 using several large, linked administrative databases at the Institute for Clinical Evaluative Sciences. The incidence, prevalence and mortality on dialysis for each cohort were determined. A multivariate Cox proportional hazards analysis, adjusting for age, sex and co-morbidity, was used to determine the independent impact of diabetes on patient survival. The average annual incidence rate of dialysis was 12 times greater in persons with diabetes (130 per 100,000) vs without diabetes (11 per 100,000). By 1999-2000, diabetic patients comprised 51% of the incident dialysis population. The average annual prevalence rate was 10 times greater in the diabetic cohort. Patients with diabetes had more co-morbidities at the start of dialysis and poorer 3 year survival (55 vs 68%; P < 0.0001). The incident and prevalent rates of dialysis for patients with diabetes mellitus are many times the rates of those without diabetes. Patients with diabetes mellitus often start dialysis with significant co-morbidities, which may contribute to the relatively high rate of mortality on dialysis.

The Costs of Safeguarding Privacy: One Research Organization's Experience

While academic health research has always observed strict vigilance in the guardianship of the rich information found in health databases, new legislation faced by all organizations ups the ante even higher. Research organizations like the Institute for Clinical Evaluative Sciences are delving into even more rigorous policies to keep sensitive information secure while preserving the value that dedicated research provides. The costs of implementing privacy protections are of great concern to Canadian researchers. This report discusses basic costs associated with privacy practices undertaken at the Institute.

Reporting of numerical and statistical differences in abstracts: improving but not optimal.

The reporting of relative risk reductions (RRRs) or absolute risk reductions (ARRs) to quantify binary outcomes in trials engenders differing perceptions of therapeutic efficacy, and the merits of P values versus confidence intervals (CIs) are also controversial. We describe the manner in which numerical and statistical difference in treatment outcomes is presented in published abstracts. A descriptive study of abstracts published in 1986 and 1996 in 8 general medical and specialty journals. controlled, intervention trials with a binary primary or secondary outcome. Seven items were recorded: raw data (outcomes for each treatment arm), measure of relative difference (e.g., RRR), ARR, number needed to treat, P value, CI, and verbal statement of statistical significance. The prevalence of these items was compared between journals and across time. Of 5,293 abstracts, 300 met the inclusion criteria. In 1986, 60% of abstracts did not provide both the raw data and a corresponding P value or CI, while 28% failed to do so in 1Dr. Hux is a Career Scientist of the Ontario Ministry of Health and receives salary support from the Institute for Clinical Evaluative Sciences in Ontario.996 ( P <.001; RRR of 53%; ARR of 32%; CI for ARR 21% to 43%). The variability between journals was highly significant ( P <.001). In 1986, 100% of abstracts lacked a measure of absolute difference while 88% of 1996 abstracts did so ( P <.001). In 1986, 98% of abstracts lacked a CI while 65% of 1996 abstracts did so ( P <.001). The provision of quantitative outcome and statistical quantitative information has significantly increased between 1986 and 1996. However, further progress can be made to make abstracts more informative.

Cardiovascular News

Cardiovascular News

Determinants of mortality from Co-morbid conditions in a population based follow-up of 39,710 newly diagnosed heart failure patients in Ontario, Canada Erika Vowinckel, Philip Jong, Peter Liu, Jack Tu. Heart &amp; Stroke/Richard Lewar Centre of Excellence, Toronto, ON, Canada, Institute for Clinical Evaluative Sciences, Toronto, ON, Canada

Determinants of mortality from Co-morbid conditions in a population based follow-up of 39,710 newly diagnosed heart failure patients in Ontario, Canada Erika Vowinckel, Philip Jong, Peter Liu, Jack Tu. Heart &amp; Stroke/Richard Lewar Centre of Excellence, Toronto, ON, Canada, Institute for Clinical Evaluative Sciences, Toronto, ON, Canada

Persistent high mortality in a population based cohort of 39,710 newly diagnosed heart failure patients in Ontario, Canada Erika Vowinckel, Phlip Jong, Peter Liu, Jack Tu. Heart &amp; Stroke/Richard Lewar Centre of Excellence, Toronto, ON, Canada, Institute for Clinical Evaluative Sciences, Toronto, ON, Canada

Persistent high mortality in a population based cohort of 39,710 newly diagnosed heart failure patients in Ontario, Canada Erika Vowinckel, Phlip Jong, Peter Liu, Jack Tu. Heart &amp; Stroke/Richard Lewar Centre of Excellence, Toronto, ON, Canada, Institute for Clinical Evaluative Sciences, Toronto, ON, Canada

Health care in Canada: incrementalism under fiscal duress.

Driven by fiscal pressures in the 1990s, Canada's provincial Medicare systems cut inpatient care, expanded community services, and consolidated hospitals under regional authorities in nine of ten provinces. Public confidence has been badly shaken by the transition. No province has successfully integrated services across the continuum of care. Home care and prescription drug coverage vary from province to province. Efforts to reform physician payment have stalled, and capacity to measure and manage the quality of care is generally underdeveloped. Thus, for the next few years, policymakers must stabilize the acute care sector, while cautiously pursuing an agenda of piece-meal reforms.

Cohort Study on Circumcision of Newborn Boys and Subsequent Risk of Urinary-Tract Infection

Population Health Sciences, Research Institute, and Paediatric Outcomes Research Team, Division of Paediatric Medicine, Hospital for Sick Children, Toronto; Institute for Clinical Evaluative Sciences in Ontario, North York; Department of Public Health Sciences, University of Toronto; Clinical Epidemiology Unit, Sunnybrook and Women's College Health Science Centre, North York; and Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada Lancet 1998;352:1813-1816