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Jack V Tu

Publications and source records attributed to Jack V Tu.

At least 73 records · Page 4Linked to original sources
PubMed2004

Automated variable selection methods for logistic regression produced unstable models for predicting acute myocardial infarction mortality.

OBJECTIVES: Automated variable selection methods are frequently used to determine the independent predictors of an outcome. The objective of this study was to determine the reproducibility of logistic regression models developed using automated variable selection methods. STUDY DESIGN AND SETTING: An initial set of 29 candidate variables were considered for predicting mortality after acute myocardial infarction (AMI). We drew 1,000 bootstrap samples from a dataset consisting of 4,911 patients admitted to hospital with an AMI. Using each bootstrap sample, logistic regression models predicting 30-day mortality were obtained using backward elimination, forward selection, and stepwise selection. The agreement between the different model selection methods and the agreement across the 1,000 bootstrap samples were compared. RESULTS: Using 1,000 bootstrap samples, backward elimination identified 940 unique models for predicting mortality. Similar results were obtained for forward and stepwise selection. Three variables were identified as independent predictors of mortality among all bootstrap samples. Over half the candidate prognostic variables were identified as independent predictors in less than half of the bootstrap samples. CONCLUSION: Automated variable selection methods result in models that are unstable and not reproducible. The variables selected as independent predictors are sensitive to random fluctuations in the data.

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PubMed2004

Time-related mortality for women after coronary artery bypass graft surgery: a population-based study.

OBJECTIVE: This study explores the relative early and late mortality risks in women and men after coronary artery bypass graft surgery. METHODS: This was a retrospective cohort study (n = 54,425 patients, 12,079 women) using clinical data for all patients who underwent isolated coronary artery bypass graft surgery in Ontario between fiscal years 1991 and 1999 obtained from the Cardiac Care Network database, with outcomes of early (< or =1 year) and late (>1 year up to 10 years) interval mortality identified through linkage to administrative databases. RESULTS: Female surgical candidates were older (65 vs 62 years, P <.0001) and higher-risk patients. The risk-adjusted survival of female patients was worse than that of male patients in the first year after coronary artery bypass graft surgery, but their long-term mortality was similar to that of male patients. The Cox proportional hazards model for early mortality had an adjusted female hazard ratio of 1.44 (95% confidence interval, 1.29-1.61; P =.02). This significantly differed from the late mortality model, which had a hazard ratio of 0.89 (95% confidence interval, 0.78-1.0; P =.06). CONCLUSIONS: Early mortality was significantly higher for women after coronary artery bypass graft surgery, despite adjustment for confounding factors. However, the long-term relative mortality risk for women appeared equivalent to or even better than that experienced by men as early as 1 year after coronary artery bypass graft surgery. This population-based study of long-term mortality supports the benefits of coronary artery bypass graft surgery for women in the current era. However, further research is needed to identify ways to reduce early postoperative mortality in women.

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PubMed2004

Use of angiotensin-converting enzyme inhibitor therapy and dose-related outcomes in older adults with new heart failure in the community.

OBJECTIVE: To evaluate the dose-related benefit of angiotensin-converting enzyme (ACE) inhibitor therapy among older adults with heart failure and to evaluate whether low-dose ACE inhibitor therapy is better than none. DESIGN: Observational cohort study. SETTING: Community-dwelling older adults in Ontario, Canada. PATIENTS/PARTICIPANTS: We identified 16539 adults 66 years or older who survived 45 days following their first heart failure hospitalization discharge. MEASUREMENT AND MAIN RESULTS: Multivariate techniques including propensity scores were used to study the association between the dose of ACE inhibitor therapy dispensed and 3 outcomes: survival, survival or heart failure rehospitalization, and survival or all-cause hospitalization at 1 year of follow-up. Logistic regression models explored the association between initial dose dispensed and subsequent dose reduction or drug cessation. Overall, 10793 (65.3%) of patients were dispensed ACE inhibitor therapy, with more than a third (3935; 36.5%) initiated on low-dose therapy. Relative to dispensing of low-dose ACE inhibitor therapy, nonuse was associated with increased mortality (hazard ratio [HR], 1.12; 95% confidence interval [CI], 1.02 to 1.22). Dispensing medium-dose therapy provided a benefit similar to low-dose (HR, 0.94; CI, 0.86 to 1.03) and dispensing of high-dose therapy was associated with improved survival benefit (HR, 0.76; CI, 0.68 to 0.85). Relative to dispensing of low-dose ACE inhibitor therapy, dispensing high-dose conferred a benefit (HR, 0.87; CI, 0.80 to 0.95) on the composite outcome of 1-year mortality or heart failure hospitalization and the composite outcome of 1-year mortality or all-cause hospitalization (HR, 0.87; CI, 0.81 to 0.93). Relative to those dispensed low-dose ACE inhibitor therapy, those initially dispensed high-dose therapy were twice as likely to have their subsequent dose reduced or the therapy discontinued (odds ratio, 2.36; CI, 2.07 to 2.69). CONCLUSION: Our findings suggest that when possible, older adults should be titrated to the higher doses of ACE inhibitor therapy evaluated in clinical trials. If older adults cannot tolerate higher doses, then low-dose ACE inhibitor therapy is superior to none. High-dose ACE inhibitor therapy is not as well tolerated as lower doses.

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PubMed2004

Secondary prevention after acute myocardial infarction in four Canadian provinces, 1997-2000.

BACKGROUND: Publication of population-based analyses of medication use after acute myocardial infarction (AMI) could encourage the use of effective secondary prevention medications. OBJECTIVE: To describe outpatient use of beta-blockers, angiotensin-converting enzyme (ACE) inhibitors, statins, calcium channel blockers and nitrates in elderly survivors of AMI over the fiscal years from 1997/98 to 1999/2000 in Nova Scotia, Quebec, Ontario and British Columbia. METHODS: Linked administrative databases were used to identify all AMI patients 65 years of age or older admitted in Quebec (n=14,880), Ontario (n=28,647) and British Columbia (n=7549) over the study period, and to measure 90-day postdischarge utilization rates of cardiac medications for these patients. A population-based clinical registry was used to measure rates of prescription at discharge for elderly patients in Nova Scotia admitted to an acute care hospital from 1997 to 2000 (n=1997). RESULTS: Utilization rates for beta-blockers, ACE inhibitors and statins increased over time, while rates for calcium channel blockers and nitrates decreased only slightly. The largest increases were for statins (Nova Scotia: 26% to 42%, Quebec: 27% to 43%; Ontario: 28% to 40%; British Columbia: 30% to 42%) and for ACE inhibitors in Ontario (55% to 65%) and Nova Scotia (46% to 68%). Of the three drugs recommended for secondary prevention, overall utilization rates for beta-blockers were highest in Nova Scotia, lowest in British Columbia, and similar in Quebec and Ontario. Rates for ACE inhibitors were highest in Ontario and similar in Quebec, Nova Scotia and British Columbia. Rates for statins were slightly higher in Quebec and British Columbia than in Ontario and Nova Scotia. The proportion of patients without a prescription for any of the recommended drugs was highest in British Columbia (20%), lowest in Nova Scotia (8%), and similar in Quebec and Ontario (Ontario: 12%; Quebec: 13%). There was marked regional variation in utilization rates within the four provinces. CONCLUSIONS: Although utilization rates for recommended cardiac medications are increasing over time, there remains room for improvement. Overall utilization rates and temporal trends are generally similar in all four provinces, but there are wide regional variations within provinces.

Adrenergic beta-Antagonists↗
PubMed2004

Cardiac procedures after an acute myocardial infarction across nine Canadian provinces.

BACKGROUND: Geographical variations in the use of invasive cardiac procedures have been documented. It remains unclear to what extent these variations exist across the Canadian provinces. OBJECTIVE: To describe variation in the use of invasive cardiac procedures and waiting times for these procedures across nine Canadian provinces. METHODS: Using longitudinal, de-identified patient data from the Canadian Institute for Health Information, records of patients who had suffered an acute myocardial infarction (AMI) in each of nine Canadian provinces between 1997/1998 and 1999/2000 were selected. Rates and median waiting times for percutaneous coronary intervention and coronary artery bypass graft surgery were calculated by age, sex and health region. RESULTS: There was a large variation in the use of and waiting times for invasive cardiac procedures across the Canadian provinces studied. In general, cardiac procedure rates in Western provinces were higher than in Eastern provinces, most notably higher than in the Maritime provinces and Ontario. In addition to interprovincial variation, there was also significant regional variation in the rates of revascularization and waiting times. Rates of percutaneous coronary intervention increased over the study period, whereas rates of bypass surgery remained relatively stable. CONCLUSIONS: Significant variation in the use of cardiac procedures after AMI exists across Canada and this April represent potential inequalities in the treatment of AMI across Canada.

Adult↗
PubMed2004

Population rates of hospitalization for atrial fibrillation/flutter in Canada.

BACKGROUND: Atrial fibrillation (AF) is the most prevalent sustained cardiac dysrhythmia and constitutes a major public health problem. AF significantly increases the risk of stroke, and anticoagulation has been shown to reduce this risk. However, Canadian data on the prevalence of AF and the use of warfarin in these patients are lacking. METHODS: International Classification of Diseases, ninth revision, codes for admissions to acute care hospitals in Canada were used to estimate the prevalence of hospitalization for AF between 1997/1998 and 1999/2000, and subsequent readmissions for stroke in all 10 provinces and overall in Canada. Warfarin use was obtained by linkage with drug benefit plans in Alberta, British Columbia, Nova Scotia and Ontario, for patients 65 years and older. RESULTS: The overall rate of hospitalization with AF between April 1, 1997, and March 31, 2000, was 582.7 per 100,000 population. The age- and sex-standardized rate rose from 513.4 to 555.3 during the three-year period of observation. The mean age was 74.4 years and 51.8% of patients were male. Of those discharged alive, 2.7% were readmitted for stroke within one year. Overall, less than one-half of the patients with AF filled a prescription for warfarin within 90 days of discharge, with only a small increase in warfarin use over the study time period. CONCLUSIONS: The rate of hospitalization with AF is increasing in Canada and is more frequent in men than in women across all age groups. Consistent with reports from other countries, warfarin use was lower than one might expect given its efficacy, with only a small increase in use over time.

Adult↗
PubMed2003

Predicting mortality among patients hospitalized for heart failure: derivation and validation of a clinical model.

CONTEXT: A predictive model of mortality in heart failure may be useful for clinicians to improve communication with and care of hospitalized patients. OBJECTIVES: To identify predictors of mortality and to develop and to validate a model using information available at hospital presentation. DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of 4031 community-based patients presenting with heart failure at multiple hospitals in Ontario, Canada (2624 patients in the derivation cohort from 1999-2001 and 1407 patients in the validation cohort from 1997-1999), who had been identified as part of the Enhanced Feedback for Effective Cardiac Treatment (EFFECT) study. MAIN OUTCOME MEASURES: All-cause 30-day and 1-year mortality. RESULTS: The mortality rates for the derivation cohort and validation cohort, respectively, were 8.9% and 8.2% in hospital, 10.7% and 10.4% at 30 days, and 32.9% and 30.5% at 1 year. Multivariable predictors of mortality at both 30 days and 1 year included older age, lower systolic blood pressure, higher respiratory rate, higher urea nitrogen level (all P<.001), and hyponatremia (P<.01). Comorbid conditions associated with mortality included cerebrovascular disease (30-day mortality odds ratio [OR], 1.43; 95% confidence interval [CI], 1.03-1.98; P =.03), chronic obstructive pulmonary disease (OR, 1.66; 95% CI, 1.22-2.27; P =.002), hepatic cirrhosis (OR, 3.22; 95% CI, 1.08-9.65; P =.04), dementia (OR, 2.54; 95% CI, 1.77-3.65; P<.001), and cancer (OR, 1.86; 95% CI, 1.28-2.70; P =.001). A risk index stratified the risk of death and identified low- and high-risk individuals. Patients with very low-risk scores (< or =60) had a mortality rate of 0.4% at 30 days and 7.8% at 1 year. Patients with very high-risk scores (>150) had a mortality rate of 59.0% at 30 days and 78.8% at 1 year. Patients with higher 1-year risk scores had reduced survival at all times up to 1 year (log-rank, P<.001). For the derivation cohort, the area under the receiver operating characteristic curve for the model was 0.80 for 30-day mortality and 0.77 for 1-year mortality. Predicted mortality rates in the validation cohort closely matched observed rates across the entire spectrum of risk. CONCLUSIONS: Among community-based heart failure patients, factors identifiable within hours of hospital presentation predicted mortality risk at 30 days and 1 year. The externally validated predictive index may assist clinicians in estimating heart failure mortality risk and in providing quantitative guidance for decision making in heart failure care.

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PubMed2003

Risk factors for death or stroke after carotid endarterectomy: observations from the Ontario Carotid Endarterectomy Registry.

BACKGROUND AND PURPOSE: Carotid endarterectomy is an effective method for preventing strokes if patients do not suffer adverse perioperative outcomes. The purpose of this study was to identify preoperative patient risk factors for adverse outcomes (death or nonfatal stroke) after carotid endarterectomy through the use of a large population-based registry from Ontario, Canada. METHODS: Medical records of all 6038 patients who underwent carotid endarterectomy in Ontario between January 1, 1994, and December 31, 1997, were abstracted from 34 hospitals. Patient characteristics (demographic data, past medical history, neurological symptoms, comorbidities, radiological findings) and 30-day postoperative death or stroke rates were analyzed with logistic regression analysis. RESULTS: The overall 30-day death or stroke rate after surgery was 6.0%. A history of transient ischemic attack or stroke (odds ratio [OR], 1.75; 95% confidence interval [CI], 1.39 to 2.20), atrial fibrillation (OR, 1.89; 95% CI, 1.29 to 2.76), contralateral carotid occlusion (OR, 1.72; 95% C.I., 1.25 to 2.38), congestive heart failure (OR, 1.80; 95% CI, 1.15 to 2.81), and diabetes (OR, 1.28; 95% CI, 1.01 to 1.63) were significant independent predictors for 30-day death or stroke. These 5 factors were combined into a simple risk score that can be used to stratify patients into different risk groups for complications after surgery. CONCLUSIONS: Several patient characteristics predict the development of stroke and death after carotid endarterectomy. These characteristics may help clinicians in patient counseling and contribute to studies "benchmarking" the outcomes of carotid surgery in the community setting.

Adult↗
PubMed2003

A comparison of several regression models for analysing cost of CABG surgery.

Investigators in clinical research are often interested in determining the association between patient characteristics and cost of medical or surgical treatment. However, there is no uniformly agreed upon regression model with which to analyse cost data. The objective of the current study was to compare the performance of linear regression, linear regression with log-transformed cost, generalized linear models with Poisson, negative binomial and gamma distributions, median regression, and proportional hazards models for analysing costs in a cohort of patients undergoing CABG surgery. The study was performed on data comprising 1959 patients who underwent CABG surgery in Calgary, Alberta, between June 1994 and March 1998. Ten of 21 patient characteristics were significantly associated with cost of surgery in all seven models. Eight variables were not significantly associated with cost of surgery in all seven models. Using mean squared prediction error as a loss function, proportional hazards regression and the three generalized linear models were best able to predict cost in independent validation data. Using mean absolute error, linear regression with log-transformed cost, proportional hazards regression, and median regression to predict median cost, were best able to predict cost in independent validation data. Since the models demonstrated good consistency in identifying factors associated with increased cost of CABG surgery, any of the seven models can be used for identifying factors associated with increased cost of surgery. However, the magnitude of, and the interpretation of, the coefficients vary across models. Researchers are encouraged to consider a variety of candidate models, including those better known in the econometrics literature, rather than begin data analysis with one regression model selected a priori. The final choice of regression model should be made after a careful assessment of how best to assess predictive ability and should be tailored to the particular data in question.

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PubMed2003

Waiting times, revascularization modality, and outcomes after acute myocardial infarction at hospitals with and without on-site revascularization facilities in Canada.

OBJECTIVES: This study was designed to determine whether admission to a Canadian hospital with on-site revascularization (invasive hospital) affected revascularization choice, timing, and outcome compared with community (non-invasive) hospitals. BACKGROUND: Health care systems in Canada are characterized by relative restraint in diffusion of tertiary cardiovascular services, with capacity for revascularization procedures concentrated in large regional referral centers. METHODS: We used linked administrative data and a clinical registry to follow-up 15,166 Ontario patients who underwent revascularization within the year after their index acute myocardial infarction (MI). Outcomes included recurrent urgent cardiac hospitalization, hospital bed-days, and death within the same year after the index admission. We adjusted for age, gender, socioeconomic status, illness severity, attending physician specialty, and academic hospital affiliation. RESULTS: After adjusting for baseline factors, patients admitted to invasive hospitals were more likely to receive angioplasty than bypass surgery (adjusted odd ratio: 1.85; 95% confidence interval: 1.68 to 2.04, p < 0.001). The converse pattern was seen for patients admitted to community hospitals. Median revascularization waiting times were significantly shorter at invasive hospitals (12 vs. 48 days, p < 0.001). Patients admitted to invasive hospitals had fewer cardiac re-admissions (41.5 vs. 68.9 events per 100 patients, p < 0.001) before their first revascularization and consumed fewer hospital bed-days (379 vs. 517 per 100 patients, p < 0.001). There were no differences in outcomes beyond revascularization. CONCLUSIONS: Outcome advantages associated with timely post-MI revascularization highlight the importance of organizing revascularization referral networks and facilitating access to revascularization for patients with acute coronary syndromes admitted to community hospitals in Canada.

Canada↗
PubMed2003

Care and outcomes of patients newly hospitalized for heart failure in the community treated by cardiologists compared with other specialists.

BACKGROUND: It is not known whether subspecialty care by cardiologists improves outcomes in heart failure patients from the community over care by other physicians. METHODS AND RESULTS: Using administrative data, we monitored 38 702 consecutive patients with first-time hospitalization for heart failure in Ontario, Canada, between April 1994 and March 1996 and examined differences in processes of care and clinical outcomes between patients attended by physicians of different disciplines. We found that patients attended by cardiologists had lower 1-year risk-adjusted mortality than those attended by general internists, family practitioners, and other physicians (28.5% versus 31.7%, 34.9%, and 35.9%, respectively; all pairwise comparisons, P<0.001). The 1-year risk-adjusted composite outcome of death and readmission for heart failure was also lower for the cardiologists compared with family practitioners and other physicians but not general internists (54.7% versus 58.1%, 58.3%, and 55.4%; P<0.001, P<0.001, and P=0.39, respectively). Multivariable hierarchical modeling demonstrated a significant physician-level effect for both outcomes in favor of the cardiologists, particularly against non-general internists. Cardiologist care was associated with higher adjusted rates of invasive interventions and postdischarge prescriptions of heart failure medications. CONCLUSIONS: In this population-based cohort, heart failure patients attended by cardiologists in hospital had lower risk of death as well as the composite risk of death or readmission than patients attended by noncardiologists. These data raise the need to identify specialty-driven differences in processes of care for heart failure patients, which may explain the observed disparity in clinical outcomes that presently favor cardiologist care.

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PubMed2003

Effectiveness of implantable defibrillators for preventing arrhythmic events and death: a meta-analysis.

OBJECTIVES: The aim of this study was to compare the effectiveness of the implantable cardioverter defibrillator (ICD) and medical strategies for prevention of arrhythmic events and death. BACKGROUND: The ICD is a potential strategy to reduce mortality in patients at risk of sudden death. METHODS: The MEDLINE, EMBASE, and Cochrane Library electronic databases were searched from January 1966 to April 2002. All published randomized controlled trials comparing ICD implantation with medical therapy were reviewed. Four independent reviewers extracted data on all-cause mortality, nonarrhythmic death, and arrhythmic death using a standardized protocol. RESULTS: Nine studies including over 5,000 patients were synthesized using both fixed-effects and random-effects models. The primary and secondary prevention trials showed a significant benefit of the ICD with respect to arrhythmic death, with relative risks (RR) of 0.34 and 0.50, respectively (both p < 0.001). The mortality benefit of the ICD was entirely attributable to a reduction in arrhythmic death (all trials: p < 0.00001). Whereas the secondary prevention trials exhibited a robust decrease in all-cause ICD mortality (RR 0.75; p < 0.001), the pooled primary prevention trials demonstrated decreased all-cause ICD mortality (RR 0.66; p < 0.05) which was dependent on selected individual trials. The disparity in ICD-related mortality reductions in the primary prevention trials was related to variability in the incidence of arrhythmic death between individual studies. CONCLUSIONS: Although the ICD decreases the risk of arrhythmic death, its impact on all-cause mortality is related to the underlying risk of arrhythmia-related death relative to competing causes. Given the cost of the device strategy, policies of targeted intervention based on the future risk of arrhythmia are warranted.

Arrhythmias, Cardiac↗
PubMed2003

Sex differences in carotid endarterectomy outcomes: results from the Ontario Carotid Endarterectomy Registry.

BACKGROUND AND PURPOSE: The existing literature provides conflicting evidence on surgical risks of carotid endarterectomy in women compared with men. We used data from a large population-based carotid surgery registry to determine whether sex differences exist in the risk of perioperative complications from carotid endarterectomy. METHODS: We analyzed data from the Ontario Carotid Endarterectomy Registry, which contains data on all patients who underwent carotid endarterectomy in the province of Ontario between 1994 and 1997. We compared the risk of death or stroke at 30 days in women and men and used multivariate analyses to adjust for age, comorbid conditions, and surgical factors. Secondary analyses compared the risks of death and/or stroke in women and men at 2 years after surgery. RESULTS: The study sample consisted of 6038 patients (35% women). The risks of perioperative stroke or death were not significantly different in women compared with men (adjusted hazard ratio, 1.10; 95% CI, 0.90 to 1.35). The combined risk of stroke or death at 2 years after surgery was also similar in women and men (adjusted hazard ratio, 1.05; 95% CI, 0.92 to 1.21). However, women were more likely to have a stroke (adjusted hazard ratio, 1.26; 95% CI, 1.05 to 1.51) and less likely to die (adjusted hazard ratio, 0.82; 95% CI, 0.68 to 0.99) within 2 years after surgery. CONCLUSIONS: Perioperative complication rates from carotid endarterectomy are similar in women and men. Women should not be discouraged from carotid endarterectomy solely on the basis of surgical risks.

Adult↗
PubMed2003

CCORT/CCS quality indicators for congestive heart failure care.

BACKGROUND: Quality indicators are measurement tools for assessing the structure, processes and outcomes of care. Although quality indicators have been developed in other countries, Canadian cardiovascular disease indicators do not exist. OBJECTIVE: To develop quality indicators for measuring and improving congestive heart failure (CHF) care in Canada. METHODS: An 11-member multidisciplinary national expert panel was selected from nominees from national medical organizations. Potential quality indicators were identified by a detailed search of published guidelines, randomized trials and outcomes studies. A two-step modified Delphi process was employed with an initial screening round of indicator ratings, followed by a national quality indicator panel meeting, where definitions of the indicators were developed using consensus methods. Indicators were designed to be measurable, using retrospective chart review and linking existing administrative databases. RESULTS: The case definition criterion was developed based on a discharge diagnosis of CHF (International Classification of Diseases, 9th revision [ICD-9] code 428.x), with diagnostic confirmation using clinical criteria. In total, 29 indicators and five test indicators were recommended. Process indicators included prescription for angiotensin-converting enzyme inhibitors, beta-blockers or warfarin (for atrial fibrillation) at hospital discharge. Nonpharmacological in hospital process indicators included evaluation of left ventricular function, weight measurement and selected patient education counselling instructions. Process indicators in the ambulatory setting included prescription and adherence to drug therapies and physician follow-up. Outcome indicators included mortality, readmissions and emergency visits. CONCLUSIONS: A set of Canadian quality indicators for CHF care encompassing organizational attributes, pharmacotherapy, investigations, counselling, continuity of care and disease outcomes has been developed. These quality indicators will serve as a foundation for future studies evaluating the quality of CHF care in Canada.

Adrenergic beta-Antagonists↗
PubMed2003

Introduction to the Canadian Cardiovascular Outcomes Research Team's (CCORT) Canadian Cardiovascular Atlas project.

The Canadian Cardiovascular Outcomes Research Team's (CCORT) Canadian Cardiovascular Atlas project was developed to provide Canadians with a national report on the state of cardiovascular health and health services in Canada. Written by a group of Canada's leading experts in cardiovascular outcomes research, the CCORT cardiac Atlas will cover a wide variety of topics ranging from cardiac risk factors and cardiac mortality rates to the treatment of patients with acute myocardial infarction and congestive heart failure and the outcomes of invasive cardiac procedures across Canada. Data in the Atlas will be presented at a national, provincial and health region level. The Atlas will be published as a series of 20 articles and chapters in future issues of The Canadian Journal of Cardiology and on CCORT's web site (www.ccort.ca). The journal version of the Atlas chapters will be written for a clinical audience and will include editorials written by invited experts, whereas the web-based version of each chapter will be written for a more general audience and will include additional supplemental information (for example, interactive colour maps and tables) that cannot be included in the journal version. Material from the Journal and the web will eventually be compiled into a book that will be distributed across Canada. This article serves as an introduction to the Atlas project and describes the rationale for and objectives of the CCORT national cardiac Atlas project.

Atlases as Topic↗
PubMed2003

The striking effect of the Heart Outcomes Prevention Evaluation (HOPE) on ramipril prescribing in Ontario.

BACKGROUND: The Heart Outcomes Prevention Evaluation (HOPE), a Canadian-led, multicentre, randomized controlled trial, demonstrated the effectiveness of the ACE inhibitor ramipril in the secondary prevention of cardiovascular disease in patients who were at high risk for cardiovascular events but did not have left ventricular dysfunction or heart failure. We studied whether HOPE affected the prescribing of ACE inhibitors generally, and ramipril specifically, in Ontario, where the trial was coordinated. METHODS: We used linked administrative databases to examine prescribing patterns for ACE inhibitors in the 1.29 million to 1.54 million elderly (aged 66 and over) residents of Ontario during the study period and specifically those with diabetes or congestive heart failure. For all new prescriptions for these drugs filled between Jan. 1, 1993, and Mar. 31, 2001, we conducted time-series analyses to measure any association with the release of the HOPE results. RESULTS: The monthly number of new prescriptions for ramipril from the time it was introduced in 1995 until HOPE's early termination, in April 1999, peaked at 58 per 100,000 elderly Ontario residents. The rate increased to 92/100,000 in May, coincident with newspaper coverage of the trial's early termination, then fell back to 63/100,000 in August. After HOPE's results were formally released, starting Aug. 31, the rate increased significantly; it peaked at 304/100,000 in May 2000 (p < 0.01). The market share of ramipril among ACE inhibitors also increased significantly (p < 0.01), both overall and among patients with diabetes or congestive heart failure. INTERPRETATION: HOPE led to a striking and unprecedented increase, over 400%, in ramipril prescribing to elderly Ontario residents, including those not eligible for the trial. Many physicians are now prescribing ramipril for patients with diabetes or congestive heart failure.

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