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Peter C Austin

Publications and source records attributed to Peter C Austin.

At least 55 records · Page 3Linked to original sources
PubMed2004

Trends in heart failure outcomes and pharmacotherapy: 1992 to 2000.

PURPOSE: To review trends in drug therapy and concomitant outcomes of elderly heart failure patients in Ontario, Canada. METHODS: Utilization of drug therapies, mortality, and rehospitalization rates from April 1992 to March 2000 were determined in 77,421 elderly (aged >/=65 years), community-based heart failure patients using linked administrative databases. Treatment effects were identified from published meta-analyses and randomized trials. The effect of drug trends on mortality and morbidity were assessed based on their absolute treatment effects. RESULTS: From 1992 to 2000, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use increased from 58% to 62% (P = 0.001) while beta-blocker use increased from 6% to 22% (P <0.001). There was a decrease in the use of treatments for which no survival advantage had been demonstrated in randomized trials, such as digitalis (49% to 35%, P <0.001), Vaughan-Williams class I antiarrhythmic agents (3.5% to 1.4%, P <0.001), and first-generation calcium antagonists (21.3% to 9.6%, P <0.001). The trends in drug therapy were associated with a 2.8% reduction in age-, sex-, and comorbidity-adjusted 1-year mortality and a 4.1% reduction in 1-year hospitalization rates. The observed trends in therapy over time explained 37% of the decrease in mortality and 30% of the decrease in rehospitalization rates. The treatment effect from beta-blockers was most pronounced, explaining 30% of the decrease in mortality and 10% of the decrease in rehospitalization rates. CONCLUSION: During 1992 to 2000, mortality and morbidity improved among elderly patients with heart failure, with increased utilization of beta-blockers contributing most to the beneficial trends in outcomes.

Adrenergic beta-Antagonists↗
PubMed2004

Inflation of the type I error rate when a continuous confounding variable is categorized in logistic regression analyses.

This paper demonstrates an inflation of the type I error rate that occurs when testing the statistical significance of a continuous risk factor after adjusting for a correlated continuous confounding variable that has been divided into a categorical variable. We used Monte Carlo simulation methods to assess the inflation of the type I error rate when testing the statistical significance of a risk factor after adjusting for a continuous confounding variable that has been divided into categories. We found that the inflation of the type I error rate increases with increasing sample size, as the correlation between the risk factor and the confounding variable increases, and with a decrease in the number of categories into which the confounder is divided. Even when the confounder is divided in a five-level categorical variable, the inflation of the type I error rate remained high when both the sample size and the correlation between the risk factor and the confounder were high.

Cohort Studies↗
PubMed2004

Socioeconomic status, service patterns, and perceptions of care among survivors of acute myocardial infarction in Canada.

CONTEXT: Some have argued that Canada's uniquely restrictive approach to private health insurance keeps the socioeconomic elite inside the public system so that their demands and influence elevate the standard of service for all Canadian citizens. The extent to which this theory is a valid representation of Canadian health care is unknown. OBJECTIVES: To explore how patients with acute myocardial infarction from different socioeconomic backgrounds perceive their care in Canada's universal health care system and to correlate patients' backgrounds and perceptions with actual care received. DESIGN, SETTING, AND PATIENTS: Prospective observational cohort study with follow-up telephone interviews of 2256 patients 30 days following acute myocardial infarction discharged from 53 hospitals across Ontario, Canada, between December 1999 and June 2002. MAIN OUTCOME MEASURES: Postdischarge use of cardiac specialty services; satisfaction with care; willingness to pay directly for faster service or more choice; and mortality according to income and education, adjusted for age, sex, ethnicity, clinical factors, onsite angiography capacity at the admitting hospital, and rural-urban residence. RESULTS: Compared with patients in lower socioeconomic strata, more affluent or better educated patients were more likely to undergo coronary angiography (67.8% vs 52.8%; P<.001), receive cardiac rehabilitation (43.9% vs 25.6%; P<.001), or be followed up by a cardiologist (56.7% vs 47.8%; P<.001). Socioeconomic differences in cardiac care persisted after adjustment for confounders. Despite receiving more specialized services, patients with higher socioeconomic status were more likely to be dissatisfied with their access to specialty care (adjusted RR, 2.02; 95% confidence interval, 1.20-3.32) and to favor out-of-pocket payments for quicker access to a wider selection of treatment options (30% vs 15% for patients with household incomes of Can 60 000 dollars or higher vs less than Can 30 000 dollars, respectively; P<.001). After adjusting for baseline characteristics, socioeconomic status was not significantly associated with mortality at 1 year following hospitalization for myocardial infarction. CONCLUSIONS: Compared with those with lower incomes or less education, upper middle-class Canadians gain preferential access to services within the publicly funded health care system yet remain more likely to favor supplemental coverage or direct purchase of services.

Adult↗
PubMed2004

An overview of the types of physicians treating acute cardiac conditions in Canada.

BACKGROUND: As the issue of physician supply and distribution increases in intensity in Canada, the scope of practice of different types of physicians becomes increasingly important. OBJECTIVE: To determine the type of physician treating hospitalized patients with acute cardiac conditions in the provinces and health regions in Canada. METHODS: Data from the Canadian Institute for Health Information Discharge Abstract Database for all available provinces and the Maintenance et Exploitation des Données pour l'Etude de la Clientèle Hospitalière for Quebec were used to determine the most responsible physician treating patients hospitalized for congestive heart failure and acute myocardial infarction from fiscal years 1997/1998 to 1999/2000. For patients whose most responsible physician was a general practitioner/family doctor, the proportion receiving a consult from a specialist (cardiologist or general internist) was calculated. The type of physician most responsible for treating the acute cardiac conditions with respect to age, sex and urban versus rural hospital was also examined. RESULTS: For approximately 50% of patients in Canada, and in 84% (99 of 118) of the health regions across Canada for which data were available, a general practitioner/family physician was the most responsible physician for patients admitted with congestive heart failure. On a national average, a specialist was the most responsible physician for treating acute myocardial infarction for 65% of patients and in 50% (57 of 115) of the health regions for which data were available. Younger patients, men and people living in urban areas were more likely to be cared for by specialists for both congestive heart failure (age, P<0.0001; sex, P<0.0001; area of admission, P<0.0001) and acute myocardial infarction (age, P<0.0001; sex, P<0.0001; area of admission, P<0.0001). CONCLUSIONS: The results of this study show that general practitioners/family physicians take a leading role in the treatment of hospitalized congestive heart failure patients, whereas cardiologists or internists are more often responsible for treating acute myocardial infarction in Canada. This distribution has important implications for cardiac educational strategies and may aid in the determination of health human resource policies.

Canada↗
PubMed2004

Estimating linear regression models in the presence of a censored independent variable.

The current study examined the impact of a censored independent variable, after adjusting for a second independent variable, when estimating regression coefficients using "naïve" ordinary least squares (OLS), "partial" OLS and full-likelihood models. We used Monte Carlo simulations to determine the bias associated with all three regression methods. We demonstrated that substantial bias was introduced in the estimation of the regression coefficient associated with the variable subject to a ceiling effect when naïve OLS regression was used. Furthermore, minor bias was transmitted to the estimation of the regression coefficient associated with the second independent variable. High correlation between the two independent variables improved estimation of the censored variable's coefficient at the expense of estimation of the other coefficient. The use of "partial" OLS and maximum-likelihood estimation were shown to result in, at most, negligible bias in estimation. Furthermore, we demonstrated that the full-likelihood method was robust under mis-specification of the joint distribution of the independent random variables. Lastly, we provided an empirical example using National Population Health Survey (NPHS) data to demonstrate the practical implications of our main findings and the simple methods available to circumvent the bias identified in the Monte Carlo simulations. Our results suggest that researchers need to be aware of the bias associated with the use of naïve ordinary least-squares estimation when estimating regression models in which at least one independent variable is subject to a ceiling effect.

Confounding Factors, Epidemiologic↗
PubMed2004

Impact of renal insufficiency on short- and long-term outcomes after cardiac surgery.

BACKGROUND: Renal insufficiency is highly prevalent in North America and has been established as a nontraditional risk factor for cardiovascular disease. Cardiovascular disease remains the primary cause of mortality in the general population and is often treated with coronary artery bypass surgery (CABG). This population-based study aimed to determine the risk of nondialysis dependent renal insufficiency (RI) on the long-term outcomes of patients who undergo CABG. METHODS: Prospectively collected data from 26,506 patients were abstracted from the Cardiac Care Network database from 9 revascularization hospitals in Ontario, Canada. Multivariate regression analysis examined associations between preoperative RI and inhospital, 30-day, and 1-year mortality according to 3 levels of serum creatinine: <120 micromol/L (normal), 120 to 180 micromol/L (mild RI), and >180 micromil/L (moderate-severe RI) and 5 levels of creatinine clearance (Cockcroft-Gault): >100 mL/min (normal), 80 to 99 mL/min (mild impairment), 60 to 79 mL/min (mild-moderate impairment), 40 to 59 mL/min (moderate impairment), and <40 mL/min (severe impairment). RESULTS: The overall inhospital, 30-day, and 1-year mortality rates were 1.90%, 2.0%, and 4.5%, respectively. Patients with RI had greater overall comorbidity. After adjustment for confounding factors, RI was associated with the greater risk of both 30-day (odds ratio 3.7, 95% CI 2.3-5.8, P <.0001) and 1-year mortality (odds ratio 4.6, 95% CI 3.3-6.4, P <.0001). CONCLUSION: Preoperative renal impairment should be recognized as a significant risk factor for mortality after CABG. A trend of increasing risk with severity of renal impairment was demonstrated for both 30-day and 1-year mortality in this large, population-based study.

Aged↗
PubMed2004

Impact of the choice of benchmark on the conclusions of hospital report cards.

BACKGROUND: Hospital report cards for outcomes following acute myocardial infarction (AMI) are being produced with increasing frequency. Implicit in the statistical methods used is the fact that hospitals are being compared with an average hospital. Prior research has demonstrated that institutional characteristics such as a high annual volume of AMI patients and academic status are associated with improved outcomes. This raises the important issue of what is an appropriate benchmark against which hospitals should be compared. The objective of the current study was to determine whether the number of hospitals identified as mortality outliers depended upon the benchmark against which hospitals are compared. METHODS: We examined all patients discharged with a diagnosis of AMI from 163 Ontario hospitals between April 1, 2000, and March 30, 2001. Logistic regression models that incorporated random provider effects were used to identify hospitals with a mortality rate significantly higher than average. The initial model included only patient characteristics, whereas additional models incorporated both patient and hospital characteristics. RESULTS: After adjusting for patient characteristics only, 3 hospitals had significantly higher mortality compared to an average-mortality hospital, while 4 hospitals had significantly lower mortality than an average-mortality hospital. However, after further adjusting for peer group, only 1 hospital was identified as having significantly lower mortality than an average-mortality institution in its peer group. CONCLUSIONS: The use of peer-group-defined rather than overall benchmarks has a substantial impact on the identification of mortality outliers. The choice of the appropriate benchmark is related to the underlying purpose of the comparison.

Benchmarking↗
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.

Aged↗
PubMed2004

Continuity of care and patient outcomes after hospital discharge.

BACKGROUND: Patients are often treated in hospital by physicians other than their regular community doctor. After they are discharged, their care is often returned to their regular community doctor and patients may not see the hospital physician. Transfer of information between physicians can be poor. We determined whether early postdischarge outcomes changed when patients were seen after discharge by physicians who treated them in the hospital. METHODS: This cohort study used population-based administrative databases to follow 938833 adults from Ontario, Canada, after they were discharged alive from a nonelective medical or surgical hospitalization between April 1, 1995, and March 1, 2000. We determined when patients were seen after discharge by physicians who treated them in the hospital, physicians who treated them 3 months prior to admission (community physicians), and specialists. The outcome of interest was 30-day death or nonelective readmission to hospital. RESULTS: Of patients studied, 7.7% died or were readmitted. The adjusted relative risk of death or readmission decreased by 5% (95% confidence interval [CI], 4% to 5%) and 3% (95% CI, 2% to 3%) with each additional visit to a hospital physician rather than a community physician or specialist, respectively. The effect of hospital physician visits was cumulative, with the adjusted risk of 30-day death or nonelective readmission reduced to 7.3%, 7.0%, and 6.7% if patients had 1, 2, or 3 visits, respectively, with a hospital rather than a community physician. The effect was consistent across important subgroups. CONCLUSIONS: Patient outcomes could be improved if their early postdischarge visits were with physicians who treated them in hospital rather than with other physicians. Follow-up visits with a hospital physician, rather than another physician, could be a modifiable factor to improve patient outcomes following discharge from hospital.

Aged↗
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

Influence of education and income on atherogenic risk factor profiles among patients hospitalized with acute myocardial infarction.

BACKGROUND: Survival after acute myocardial infarction (AMI) varies with socioeconomic status. It is unknown whether these differences can be attributed, in part, to variations in the prevalence of atherogenic risk factors preceding the index AMI event. OBJECTIVES: To examine how cardiovascular risk factors varied according to person-level indicators of income and education among a cohort of younger patients (younger than 65 years of age) hospitalized with AMI in Ontario. METHODS: The Socio-Economic and Acute Myocardial Infarction study (SESAMI) prospectively assembled a cohort of 3335 patients hospitalized with AMI who consented to participate (75% consent rate) from 53 of 57 large-volume institutions (100 AMI cases per year or more) throughout Ontario between December 1, 1999, and June 1, 2002. Given the known challenges inherent in characterizing the socioeconomic status in elderly patients and the ubiquity of atherosclerosis in elderly persons, the study focused on 1635 nonelderly participants. The relationship between income or education and cardiovascular risk factors, after adjustment for age, sex, ethnoracial factors and geography (urban-rural status) was examined. RESULTS: The prevalence of diabetes, hypertension, smoking and pre-existing heart disease was higher among poorer, less educated patients, as were the total number of cardiovascular risk factors. After adjusting for baseline factors, both income (adjusted OR 0.50, 95% CI 0.31 to 0.82, P=0.006) and education (adjusted OR 0.52, 95% CI 0.31 to 0.87, P=0.01) were independently associated with cardiovascular risk factors or pre-existing heart disease. There were no significant interactions between income, education and baseline cardiovascular risk. CONCLUSIONS: Outcome differences across socioeconomic strata following AMI may reflect major income- and education-related differences in atherogenic risk profile.

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.

Aged↗
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.

Aged↗
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.

Aged↗
PubMed2003

Differences in operative mortality between high- and low-volume hospitals in Ontario for 5 major surgical procedures: estimating the number of lives potentially saved through regionalization.

BACKGROUND: Previous research has shown that persons undergoing certain high-risk surgical procedures at high-volume hospitals (HVHs) have a lower risk of postoperative death than those undergoing surgery at low-volume hospitals (LVHs). We estimated the absolute number of operative deaths that could potentially be avoided if 5 major surgical procedures in Ontario were restricted to HVHs. METHODS: We collected data on all persons who underwent esophagectomy (613), colon or rectal resection for colorectal cancer (18 898), pancreaticoduodenectomy (686), pulmonary lobectomy or pneumonectomy for lung cancer (5156) or repair of an unruptured abdominal aortic aneurysm (AAA) (6279) in Ontario from Apr. 1, 1994, to Mar. 31, 1999. We calculated the excess number of operative deaths (defined as deaths in the period from the day of the operation to 30 days thereafter), adjusted for age, sex and comorbidity, among the 75% of persons treated in LVHs, as compared with the 25% treated in the highest-volume quartile of hospitals. Bootstrap methods were used to estimate 95% confidence intervals (CIs). RESULTS: Of the 31 632 persons undergoing any of the 5 procedures, 1341 (4.24%) died within 30 days of surgery. If the 75% of persons treated at the LVHs had instead been treated at the HVHs, the annual number of lives potentially saved would have been 4 (95% CI, 0 to 9) for esophagectomy, 6 (95% CI, 1 to 11) for pancreaticoduodenectomy, 1 (95% CI, -10 to 13) for major lung resection and 14 (95% CI, 1 to 25) for repair of unruptured AAA. For resection of colon or rectum, the regionalization strategy would not have saved any lives, and 17 lives (95% CI, 36 to -3) would potentially have been lost. INTERPRETATION: A small number of operative deaths are potentially avoidable by performing 4 of 5 complex surgical procedures only at HVHs in Ontario. In determining health policy, the most compelling argument for regionalizing complex surgical procedures at HVHs may not be the prevention of a large number of such deaths.

Age Distribution↗