Dennis T Ko

Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada

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Publications (118)1127.89 Total impact

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    ABSTRACT: Ezetimibe use has steadily increased in Canada during the past decade even in the absence of evidence demonstrating a beneficial effect on clinical outcomes. Among the 4 most populated provinces in Canada, there is a gradient in the restrictiveness of ezetimibe in public-funded formularies (most to least strict: British Columbia, Alberta, Quebec, and Ontario). The effect of formulary policy on the use of ezetimibe over time is unknown.
    Circulation Cardiovascular Quality and Outcomes 06/2014; · 5.66 Impact Factor
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    ABSTRACT: Higher-risk patients may not receive evidence-based therapy because of limited life expectancy, which is a composite measure that encompasses many patient factors, including age, frailty, and comorbidities. In this study, we evaluated the extent to which treatment care gaps can be explained by a difference in projected life expectancy.
    Circulation Cardiovascular Quality and Outcomes 06/2014; · 5.66 Impact Factor
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    ABSTRACT: We previously found that the use of ezetimibe increased rapidly with different patterns between the United States (US) and Canada prior to the landmark Ezetimibe and Simvastatin in Hypercholesterolemia Enhance Atherosclerosis Regression (ENHANCE) trial, which was reported in January 2008, and failed to show that the drug slowed the progression of atherosclerosis. What is not known is how practice in the 2 countries changed after the ENHANCE trial. We examined ezetimibe use trends in the US and Canada before and after the reporting of the ENHANCE trial. We conducted a population-based, retrospective, time-series analysis using the data collected by IMS Health in the US and CompuScript in Canada from January 1, 2002, to December 31, 2009. The main outcome measure was monthly number of prescriptions for ezetimibe-containing products. The monthly number of ezetimibe prescriptions/100,000 population rose from 6 to 1,082 in the US from November 2002 to January 2008, then significantly declined to 572/100,000 population by December 2009 after the release of the ENHANCE trial, a decrease of 47.1% (P < .001). In contrast, in Canada, use continuously rose from 2 to 495/100,000 population from June 2003 to December 2009 (P = .2). United States expenditures totaled $2.24 billion in 2009. Ezetimibe remains commonly used in both the US and Canada. Ezetimibe use has decreased in the US post-ENHANCE, whereas use has gradually but steadily increased in Canada. The diverging patterns of ezetimibe use in the US and Canada require further investigation, as they reveal that a common evidence base is eliciting very different utilization patterns in neighboring countries.
    American heart journal 05/2014; 167(5):683-9. · 4.65 Impact Factor
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    ABSTRACT: Randomized studies have shown optimal medical therapy to be as efficacious as revascularization in stable ischemic heart disease (IHD). It is not known if these efficacy results are reflected by real-world effectiveness. To evaluate the comparative effectiveness of routine medical therapy versus revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) in stable IHD. Observational cohort study. Stable IHD patients from 1 October 2008 to 30 September 2011, identified using a Registry of all angiography patients in Ontario, Canada. Revascularization, defined as PCI/CABG within 90 days after index angiography. Death, myocardial infarction (MI) or repeat PCI/CABG. Revascularization was compared to medical therapy using a) multivariable Cox-proportional hazard models with therapy strategy treated as a time-varying covariate; and b) a propensity score matched analysis. Post-angiography medication use was determined. We identified 39,131 stable IHD patients, of whom 15,139 were treated medically, and 23,992 were revascularized (PCI = 15,604; CABG = 8,388). Mean follow-up was 2.5 years. Revascularization was associated with fewer deaths (HR 0.76; 95 % CI 0.68-0.84; p < 0.001) ,MIs (HR 0.78; 95 % CI 0.72-0.85; p < 0.001) and repeat PCI/CABG (HR 0.59; 95 % CI 0.50-0.70; p < 0.001) than medical therapy. In the propensity-matched analysis of 12,362 well-matched pairs of revascularized and medical therapy patients, fewer deaths (8.6 % vs 12.7 %; HR 0.75; 95 % CI 0.69-0.81; p < 0.001) , MIs (11.7 % vs 14.4 %; HR 0.84; 95 % CI 0.77-0.93 p < 0.001) and repeat PCI/CABG ( 17.4 % vs 24.1 %;HR 0.67; 95 % 0.63-0.71; p < 0.001) occurred in revascularized patients, over the 4.1 years of follow-up. The revascularization patients had higher uptake of clopidogrel (70.3 % vs 27.2 %; p < 0.001), β-blockers (78.2 % vs 76.7 %; p = 0.010), and statins (94.7 % vs 91.5 %, p < 0.001) in the 1-year post-angiogram. Stable IHD patients treated with revascularization had improved risk-adjusted outcomes in clinical practice, potentially due to under-treatment of medical therapy patients.
    Journal of General Internal Medicine 03/2014; · 3.28 Impact Factor
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    ABSTRACT: Although multidisciplinary heart failure (HF) clinics are efficacious, it is not known how patient factors or HF clinic structural indicators and process measures have an impact on the cumulative health care costs. In this retrospective cohort study using administrative databases in Ontario, Canada, we identified 1216 HF patients discharged alive after an acute care hospitalization in 2006 and treated at a HF clinic. The primary outcome was the cumulative 1-year health care costs. A hierarchical generalized linear model with a logarithmic link and gamma distribution was developed to determine patient-level and clinic-level predictors of cost. The mean 1-year cost was $27,809 (range, $69 to $343,743). There was a 7-fold variation in the mean costs by clinic, from $14,670 to $96,524. Delays in being seen at a HF clinic were a significant patient-level predictor of costs (rate ratio 1.0015 per day; P<0.001). Being treated at a clinic with >3 physicians was associated with lower costs (rate ratio 0.78; P=0.035). Unmeasured patient-level differences accounted for 97.4% of the between-patient variations in cost. The between-clinic variation in costs decreased by 16.3% when patient-level factors were accounted for; it decreased by a further 49.8% when clinic-level factors were added. From a policy perspective, the wide spectrum of HF clinic structure translates to inefficient care. Greater guidance as to the type of patient seen at a HF clinic, the timeliness of the initial visit, and the most appropriate structure of the HF clinics may potentially result in more cost-effective care.
    Medical care 03/2014; 52(3):272-9. · 3.24 Impact Factor
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    ABSTRACT: Aims: Our objective was to evaluate the relationship between coronary chronic total occlusion (CTO) treatment strategy and quality of life improvements. Methods and results: This multicentre prospective cohort study enrolled consecutive CTO patients undergoing a non-urgent coronary angiogram who completed the Seattle Angina Questionnaire (SAQ) and EQ-5D at baseline and at one year. Strategies were: i) medical therapy, ii) PCI to non-CTO, iii) PCI to CTO, and iv) CABG. Multivariable regression models compared quality of life changes over time among strategies, accounting for repeat measures per patient. In our cohort of 387 patients, 154 underwent medical therapy, 83 had PCI to the non-CTO artery, 104 underwent CABG, and 46 underwent PCI to the CTO. Medically treated patients had no improvement on any SAQ domains. Patients with revascularisation of the CTO territory with either PCI or CABG had significant improvements in the physical limitation (PCI to CTO 60.5-76.4; CABG 61.6-80.1; p<0.001), angina frequency (PCI to CTO 79.0-92.7; CABG 82.1-97.9; p<0.001), and disease perception (PCI to CTO 50.5-75.0; CABG 50.2-80.0; p<0.001) domains. In non-CTO PCI patients, improvement was restricted to the angina frequency (82.8-93.3; p<0.001), and disease perception (53.8-71.4; p<0.001) domains. Conclusions: CTO territory revascularisation was associated with quality of life improvements.
    EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology 02/2014; 9(10):1165-72. · 3.17 Impact Factor
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    ABSTRACT: Clinical guidelines emphasize medical therapy as the initial approach to the management of patients with stable coronary artery disease (CAD). However, the extent to which medical therapy is applied before and after percutaneous coronary intervention (PCI) in contemporary clinical practice is uncertain. We evaluated medication use for patients with stable CAD undergoing PCI, and assessed whether the COURAGE study altered medication use in the Canadian healthcare system.
    Journal of the American Heart Association. 01/2014; 3(4).
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    ABSTRACT: To describe rates and risk factors for prolonged postoperative use of opioids in patients who had not previously used opioids and undergoing major elective surgery. Population based retrospective cohort study. Acute care hospitals in Ontario, Canada, between 1 April 2003 and 31 March 2010. 39 140 opioid naïve patients aged 66 years or older who had major elective surgery, including cardiac, intrathoracic, intra-abdominal, and pelvic procedures. Prolonged opioid use after discharge, as defined by ongoing outpatient prescriptions for opioids for more than 90 days after surgery. Of the 39 140 patients in the entire cohort, 49.2% (n=19 256) were discharged from hospital with an opioid prescription, and 3.1% (n=1229) continued to receive opioids for more than 90 days after surgery. Following risk adjustment with multivariable logistic regression modelling, patient related factors associated with significantly higher risks of prolonged opioid use included younger age, lower household income, specific comorbidities (diabetes, heart failure, pulmonary disease), and use of specific drugs preoperatively (benzodiazepines, selective serotonin reuptake inhibitors, angiotensin converting enzyme inhibitors). The type of surgical procedure was also highly associated with prolonged opioid use. Compared with open radical prostatectomies, both open and minimally invasive thoracic procedures were associated with significantly higher risks (odds ratio 2.58, 95% confidence interval 2.03 to 3.28 and 1.95 1.36 to 2.78, respectively). Conversely, open and minimally invasive major gynaecological procedures were associated with significantly lower risks (0.73, 0.55 to 0.98 and 0.45, 0.33 to 0.62, respectively). Approximately 3% of previously opioid naïve patients continued to use opioids for more than 90 days after major elective surgery. Specific patient and surgical characteristics were associated with the development of prolonged postoperative use of opioids. Our findings can help better inform understanding about the long term risks of opioid treatment for acute postoperative pain and define patient subgroups that warrant interventions to prevent progression to prolonged postoperative opioid use.
    BMJ (online) 01/2014; 348:g1251. · 17.22 Impact Factor
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    ABSTRACT: Background Chest pain is one of the most common reasons for presentation to the emergency department (ED), however there is a paucity of data evaluating the impact of physician follow-up and subsequent management. To evaluate the impact of physician follow-up for low risk chest pain patients after ED assessment. Methods We performed a retrospective observational study of low risk chest pain patients who were assessed and discharged home from an Ontario ED. Low risk was defined as ≥50 years of age, and no diabetes or pre-existing cardiovascular disease. Follow-up within 30 days was stratified as: a) no-physician, b) primary care physician (PCP) alone, c) PCP with cardiologist, and d) cardiologist alone. The primary outcome was death or myocardial infarction (MI) at one-year. Results Among 216,527 patients, 29% had no-physician, 60% had PCP alone, 8% had PCP with cardiologist, and 4% had cardiologist alone follow-up after ED discharge. The mean age of the study cohort was 64.2 years and 42% of the patients were male. After adjusting for important differences in baseline characteristics between physician follow-up groups, the adjusted hazard ratios for death or MI were 1.07 (95% CI, 1.00 to 1.14) for the PCP group, 0.81 (95% CI, 0.72 to 0.91) for the PCP with cardiologist group, and 0.87 (95% CI, 0.74 to 1.02) for the cardiologist alone group, as compared to patients who had no follow-up. Conclusion In this cohort of low risk patients who presented to an ED with chest pain, follow up with a PCP and cardiologist was associated with significantly reduced risk of death or MI at one-year.
    American Heart Journal. 01/2014;
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    ABSTRACT: Background There is increasing demand for transcatheter aortic valve replacement (TAVR) as the primary treatment option for patients with severe aortic stenosis (AS) who are high risk surgical candidates or inoperable. We used mathematical simulation models to estimate the hypothetical effectiveness of TAVR with increasing wait-times. Methods We applied discrete event modelling, using data from the Placement of Aortic Transcatheter Valves (PARTNER) trials. We compared TAVR to medical therapy in the inoperable cohort, and compared TAVR to conventional aortic valve surgery in the high risk cohort. One-year mortality and wait-time deaths were calculated in different scenarios by varying TAVR wait-times from 10 days to 180 days, while maintaining a constant wait-time for surgery at a mean of 15.6 days Results In the inoperable cohort, the 1-year mortality for medical therapy was 50%. When the TAVR wait-time was 10 days, the TAVR wait-time mortality was 1.9% with a 1 year mortality of 31.5%. TAVR wait-time deaths increased to 28.9% with a 180-day wait, with a 1-year mortality of 41.4%. In the high risk cohort, the wait-time deaths and 1-year mortality for the surgical patients were 2.5% and 27% respectively. The TAVR wait-time deaths increased from 2.2% with a 10-day wait to 22.4% with a 180-day wait, and a corresponding increase in 1-year mortality from 24.5% to 32.6%. Mortality with TAVR exceeded surgery when TAVR wait-times exceeded 60 days. Conclusion Modest increases in TAVR wait-times have substantial impact on the effectiveness of TAVR in both inoperable patients and high risk surgical candidates.
    The Canadian journal of cardiology 01/2014; · 3.12 Impact Factor
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    ABSTRACT: Background Extensive research has demonstrated the importance of traditional cardiovascular risk factors in predicting acute coronary events. Our main objective was to evaluate the relationship between traditional risk factors and the presence of obstructive coronary artery disease (CAD), and to explore potential differences in men versus women. Methods An observational study was conducted in a population-based cohort of stable patients who underwent cardiac catheterization in Ontario, Canada. We examined the relationship of diabetes, hypertension, hyperlipidemia and smoking with the presence of obstructive CAD in men and women using multivariable logistic regression models. Results Of the 46,490 patients who were included in our study, 61.2% were men and 38.8% were women. We found that 97% of patients with obstructive CAD had at least one conventional cardiovascular risk factor. The adjusted odds ratios (OR) for obstructive CAD in women with diabetes (OR 1.51), hypertension (OR 1.38), and smoking (OR 1.39) were statistically significantly higher than in men (OR 1.20 for diabetes, OR 1.08 for hypertension, OR 1.14 for smoking, P < 0.001). The sex difference was even greater for patients with multiple risk factors. For example, the association with obstructive CAD in women with four cardiac risk factors (OR 4.30;95%CI 3.49-5.28) was almost doubled when compared to men (OR 2.26;95%CI 1.99-2.57, P < 0.001). Conclusions Almost all patients with stable CAD undergoing cardiac catheterization had at least one traditional cardiac risk factor. Importantly, the association between multiple cardiac risk factors and the presence of obstructive CAD is substantially stronger in women than men.
    The Canadian journal of cardiology 01/2014; · 3.12 Impact Factor
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    ABSTRACT: Canadians of Chinese descent, represent one of the fastest growing visible minority groups in Canada, (as well as the second largest), but relatively little is known about the clinical features of heart failure (HF) in Chinese-Canadian versus non-Chinese Canadian patients. We conducted a population-based analysis of urban patients hospitalized in Ontario, Canada for the first time with a most responsible diagnosis of HF between April 1, 1995 and March 31, 2008. Among the 99,278 patients, 1,339 (1.3%) were classified as Chinese using a previously validated list of Chinese surnames. Through linkage to other administrative databases, we compared the clinical characteristics, pharmacological management, and outcomes of Chinese versus non-Chinese HF patients. Ischemic heart disease was identified as the possible etiology of HF in a greater proportion of non-Chinese patients (47.7% vs. 35.3%; p < 0.001) whereas hypertension (26.1% vs. 16.1%; p < 0.001) and valvular heart disease (11.6% vs. 7.2%; p < 0.001) were relatively more common in Chinese patients. Chinese patients were prescribed angiotensin-converting enzyme (ACE) inhibitors less frequently (57.5% vs. 66.4%, p < 0.001) and angiotensin receptor blockers (ARBs) more frequently (17.4% vs. 8.9%, p < 0.001) compared to non-Chinese patients. They were also less likely to be adherent to ACE inhibitors over a 1-year follow up period. However, the 1-year case-fatality rates were comparable between the Chinese (31.7%) and non-Chinese (30.2%) subjects (p = 0.24). There are important differences in the causes and medical management of HF in Chinese and non-Chinese patients residing in Canada. Despite these differences, the long-term outcomes of HF patients were similar.
    BMC Cardiovascular Disorders 12/2013; 13(1):114. · 1.46 Impact Factor
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    ABSTRACT: IMPORTANCE Ischemic heart disease is the leading cause of death globally. Coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI) are the revascularization options for ischemic heart disease. However, the choice of the most appropriate revascularization modality is controversial in some patient subgroups. OBJECTIVE To summarize the current evidence comparing the effectiveness of CABG surgery and PCI in patients with unprotected left main disease (ULMD, in which there is >50% left main coronary stenosis without protective bypass grafts), multivessel coronary artery disease (CAD), diabetes, or left ventricular dysfunction (LVD). EVIDENCE REVIEW A search of OvidSP MEDLINE, EMBASE, and Cochrane databases between January 2007 and June 2013, limited to randomized clinical trials (RCTs) and meta-analysis of trials and/or observational studies comparing CABG surgery with PCI was performed. Bibliographies of relevant studies were also searched. Mortality and major adverse cardiac and cerebrovascular events (MACCE, defined as all-cause mortality, myocardial infarction, stroke, and repeat revascularization) were reported wherever possible. FINDINGS Thirteen RCTs and 5 meta-analyses were included. CABG surgery should be recommended in patients with ULMD, multivessel CAD, or LVD, if the severity of coronary disease is deemed to be complex (SYNTAX >22) due to lower cardiac events associated with CABG surgery. In cases in which coronary disease is less complex (SYNTAX ≤22) and/or the patient is a higher surgical risk, PCI should be considered. For patients with diabetes and multivessel CAD, CABG surgery should be recommended as standard therapy irrespective of the severity of coronary anatomy, given improved long-term survival and lower cardiac events (5-year MACCE, 18.7% for CABG surgery vs 26.6% for PCI; P = .005). Overall, the incidence of repeat revascularization is higher after PCI, whereas stroke is higher after CABG surgery. Current literature emphasizes the importance of a heart-team approach that should consider coronary anatomy, patient characteristics, and local expertise in revascularization options. Literature pertaining to revascularization options in LVD is scarce predominantly due to LVD being an exclusion factor in most studies. CONCLUSIONS AND RELEVANCE Both CABG surgery and PCI are reasonable options for patients with advanced CAD. Patients with diabetes generally have better outcomes with CABG surgery than PCI. In cases of ULMD, multivessel CAD, or LVD, CABG surgery should be favored in patients with complex coronary lesions and anatomy and PCI in less complicated coronary disease or deemed a high surgical risk. A heart-team approach should evaluate coronary disease complexity, patient comorbidities, patient preferences, and local expertise.
    JAMA The Journal of the American Medical Association 11/2013; 310(19):2086-95. · 29.98 Impact Factor
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    ABSTRACT: The rate of conversion of abstracts presented at scientific meetings into peer-reviewed published manuscripts is an important metric for medical societies, because it facilitates translation of scientific knowledge into practice. We determined the rate and predictors of conversion of scientific abstracts presented at the Canadian Cardiovascular Congress (CCC) from 2006 to 2010 into peer-reviewed article publications within 2 years of their initial presentation. Using a previously validated computer algorithm, we searched the International Statistical Institute Web of Science to identify peer-reviewed full manuscript publications of these abstracts. A multivariable logistic regression was used to identify independent factors associated with successful publication. From 2006 to 2010, 3565 abstracts were presented at the CCC. Overall 24.1% of presented abstracts were published within 2 years of the conference. Mean impact factor for publications was 5.2 (range, 0.4-53.2). The type of presentation (for poster vs oral; odds ratio, 0.71; 95% confidence interval, 0.60-0.83; P < 0.001) and category of presentation (P < 0.001) were significantly associated with successful publication. Late breaking abstracts and those related to cancer and clinical sciences were more likely to be published, compared with prevention, vascular biology, and pediatrics. In conclusion, the publication rate at the CCC is only marginally lower than that reported for large international North American and European cardiology conferences (30.6%). Efforts should focus on several identified barriers to improve conversion of abstracts to full report publication.
    The Canadian journal of cardiology 11/2013; 29(11):1520-3. · 3.12 Impact Factor
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    ABSTRACT: Although practice guidelines recommend that perioperative β-blockade be initiated at least several days to weeks before noncardiac surgery is performed, the minimum required period of preoperative therapy is unclear. Population-based administrative databases were used to conduct a cohort study of 48,103 patients aged ≥ 66 years who underwent major elective noncardiac surgery in Ontario, Canada and received preoperative β-blocker therapy. We used multivariable logistic regression to determine the association of duration of preoperative β-blocker treatment (classified as 1-7 days, 8-30 days, and ≥ 31 days) with 30-day mortality, 30-day myocardial infarction (MI), 30-day ischemic stroke, and 1-year mortality. The duration of preoperative β-blocker treatment was 1-7 days in 1105 patients (2.3%), 8-30 days in 2639 patients (5.5%), and ≥ 31 days in 44,269 patients (92.0%). Compared with ≥ 31 days of preoperative therapy, 1-7 days of therapy was associated with increased 30-day mortality (odds ratio [OR], 1.49; 95% confidence interval [CI], 1.03-2.16; P = 0.03], whereas 8-30 days of therapy was not (OR, 0.95; 95% CI, 0.69-1.31; P = 0.77). One to 7 days of preoperative therapy was not significantly associated with 1-year mortality (OR, 1.06; 95% CI, 0.84-1.35; P = 0.62), 30-day MI (OR, 1.26; 95% CI, 0.92-1.71; P = 0.15), or 30-day ischemic stroke (OR, 1.37; 95% CI, 0.64-2.94; P = 0.41). Initiation of β-blocker therapy 1-7 days before noncardiac surgery is associated with increased 30-day mortality. The findings merit further evaluation by randomized trials.
    The Canadian journal of cardiology 10/2013; · 3.12 Impact Factor
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    ABSTRACT: Coronary angiograms are important in the diagnostic workup of patients with suspected coronary artery disease. However, little is known about the clinical predictors of normal angiograms and whether this rate varies across different cardiac centers in Ontario. We conducted a study using the Cardiac Care Network Variations in Revascularization Practice in Ontario database of 2,718 patients undergoing an index cardiac catheterization for an indication of stable angina between April 2006 and March 2007 at one of 17 cardiac hospitals in Ontario. We determined predictors of normal coronary angiograms (0% coronary stenosis) and compared rates of patients with normal catheterizations across centers. Overall, 41.9% of patients with stable angina had a normal catheterization. A multivariate model demonstrated female gender to be the strongest predictor of a normal angiogram (odds ratio 3.55, 95% CI 2.93-4.28). In addition, atypical ischemic symptoms or no symptoms, the absence of diabetes, hyperlipidemia, smoking history, peripheral vascular disease, and angiography performed at a nonteaching site were associated with higher rates of normal catheterization. The rate of normal angiograms studied varied from 18.4% to 76.9% across hospitals and was more common in community compared with academic settings (47.1% vs 35.4%, P < .001). The absence of traditional cardiac risk factors, female gender, and lack of typical angina symptoms are all associated with a higher frequency of normal cardiac catheterizations. The wide variation in Ontario in the frequency of normal angiograms in patients with stable angina suggests that there are opportunities to improve patient case selection.
    American heart journal 10/2013; 166(4):694-700. · 4.65 Impact Factor
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    ABSTRACT: Percutaneous coronary intervention (PCI) with either drug-eluting stents (DES) or bare metal stents (BMS) reduces angina and repeat procedures compared with optimal medical therapy alone. It remains unclear if these benefits are sufficient to offset their increased costs and small increase in adverse events. . Cost utility analysis of initial medical therapy v. PCI with either BMS or DES. . Markov cohort decision model. Data Sources. Propensity-matched observational data from Ontario, Canada, for baseline event rates. Effectiveness and utility data obtained from the published literature, with costs from the Ontario Case Costing Initiative. Target Population. Patients with stable coronary artery disease, confirmed after angiography, stratified by risk of restenosis based on diabetic status, lesion size, and lesion length. Time Horizon. Lifetime. Perspective. Ontario Ministry of Health and Long Term Care. Interventions. Optimal medical therapy, PCI with BMS or DES. Outcome MEASURES: . Lifetime costs, quality-adjusted life years (QALYs), and the incremental cost-effectiveness ratio (ICER). of Base Case Analysis. In the overall population, medical therapy had the lowest lifetime costs at $22,952 v. $25,081 and $25,536 for BMS and DES, respectively. Medical therapy had a quality-adjusted life expectancy of 10.1 v. 10.26 QALYs for BMS, producing an ICER of $13,271/QALY. The DES strategy had a quality-adjusted life expectancy of only 10.20 QALYs and was dominated by the BMS strategy. This ranking was consistent in all groups stratified by restenosis risk, except diabetic patients with long lesions in small arteries, in whom DES was cost-effective compared with medical therapy (ICER of $18,826/QALY). Limitations. There is the possibility of residual unobserved confounding. . In patients with stable coronary artery disease, an initial BMS strategy is cost-effective.
    Medical Decision Making 07/2013; · 2.89 Impact Factor
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    ABSTRACT: IMPORTANCE Prior studies have shown that physicians in New York State (New York) perform twice as many cardiac catheterizations per capita as those in Ontario for stable patients. However, the role of patient selection in these findings and their implications for detection of obstructive coronary artery disease (CAD) are largely unknown. OBJECTIVE To evaluate the extent of obstructive CAD and to compare the probability of detecting obstructive CAD for patients undergoing cardiac catheterization. DESIGN, SETTING, AND PATIENTS An observational study was conducted involving patients without a history of cardiac disease who underwent elective cardiac catheterization between October 1, 2008, and September 30, 2011. Obstructive CAD was defined as diameter stenosis of 50% or more in the left main coronary artery or stenosis of 70% or more in a major epicardial vessel. MAIN OUTCOMES AND MEASURES Observed rates and predicted probabilities of obstructive CAD. Predicted probabilities were estimated using logistic regression models. RESULTS A total of 18 114 patients from New York and 54 933 from Ontario were included. The observed rate of obstructive CAD was significantly lower in New York at 30.4% (95% CI, 29.7%-31.0%) than in Ontario at 44.8% (95% CI, 44.4%-45.3%; P < .001). The percentage of patients with left main or 3-vessel CAD was also significantly lower in New York than in Ontario (7.0% [95% CI, 6.6%-7.3%] vs 13.0% [95% CI, 12.8%-13.3%]; P < .001). In New York, a substantially higher percentage of patients with low predicted probability of obstructive CAD underwent cardiac catheterization; for example, only 19.3% (95% CI, 18.7%-19.9%) of patients undergoing cardiac catheterization in New York had a greater than 50% predicted probability of having obstructive CAD than those in Ontario at 41% (95% CI, 40.6%-41.4%; P < .001). At 30 days, crude mortality for patients undergoing cardiac catheterization was slightly higher in New York at 0.65% (90 of 13 824; 95% CI, 0.51%-0.78%) than in Ontario at 0.38% (153 of 40 794; 95% CI, 0.32%-0.43%; P < .001). CONCLUSIONS AND RELEVANCE In Ontario compared with New York State, patients undergoing elective cardiac catheterization were significantly more likely to have obstructive CAD. This appears to be related to a higher percentage of patients in New York with low predicted probability of CAD undergoing cardiac catheterization.
    JAMA The Journal of the American Medical Association 07/2013; 310(2):163-9. · 29.98 Impact Factor
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    ABSTRACT: Ethnic minority groups in the United States are at increased risk of developing cardiovascular diseases, experiencing adverse outcomes, and receiving suboptimal treatment. Such discrepancies may be related to a difference in race-specific outcomes in the management of cardiovascular diseases. However, little is known about the reporting and representation of ethnic minorities in major cardiovascular trials. A systematic review of major cardiovascular randomized controlled trials published in The Journal of the American Medical Association, The Lancet, and The New England Journal of Medicine between 1997 and 2010 was performed. We determined the reporting rate of the following ethnic minority groups in studies that enrolled American patients: whites, African Americans, Asians, and Hispanics. A total of 250 randomized controlled trials that enrolled 1,103,694 patients were included in the systematic review. Among them, 56% (n = 140) of the trials reported information on race. No significant temporal changes in racial reporting were observed during the study period (P = .21). The median enrollment rate in trials for whites, African Americans, Hispanics, and Asians was 86%, 7%, 6%, and 4%, respectively. When compared with the population prevalence of disease burden, we found that whites were overrepresented (88% vs 78%, P < .001), whereas African Americans were underrepresented (3% vs 11%, P < .001), in trials of coronary artery disease. Despite significant changes in the ethnic composition of the United States, we found that only about half of all major cardiovascular trials reported any racial information. Underrepresentation of ethnic minority groups in cardiovascular trials was observed.
    American heart journal 07/2013; 166(1):52-7. · 4.65 Impact Factor
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    ABSTRACT: Despite the availability of several acute coronary syndrome (ACS) prognostic risk scores, there is no appropriate score for early-risk stratification at the time of the first medical contact with patients with ACS. The primary objective of this study is to develop a simple risk score that can be used for early-risk stratification of patients with ACS. We derived the risk score from the Acute Myocardial Infarction in Quebec and Canada ACS-1 registries and validated the risk score in 4 other large data sets of patients with ACS (Canada ACS-2 registry, Canada-GRACE, EFFECT-1, and the FAST-MI registries). The final risk score is named the Canada Acute Coronary Syndrome Risk Score (C-ACS) and ranged from 0 to 4, with 1 point assigned for the presence of each of these variables: age ≥75 years, Killip >1, systolic blood pressure <100 mm Hg, and heart rate >100 beats/min. The primary end points were short-term (inhospital or 30-day) and long-term (1- or 5-year) all-cause mortality. The C-ACS has good predictive values for short- and long-term mortality of patients with ST-segment elevation myocardial infarction and non-ST-segment elevation ACS. The negative predictive value of a C-ACS score ≥1 is excellent at ≥98% (95% CI 0.97-0.99) for short-term mortality and ≥93% (95% CI 0.91-0.96) for long-term mortality. In other words, a C-ACS score of 0 can potentially identify correctly ≥97% short-term survivors and ≥91% long-term survivors. The C-ACS risk score permits rapid stratification of patients with ACS. Because this risk score is simple and easy to memorize and calculate, it can be rapidly applied by health care professionals without advanced medical training.
    American heart journal 07/2013; 166(1):58-63. · 4.65 Impact Factor

Publication Stats

2k Citations
1,127.89 Total Impact Points

Institutions

  • 2006–2014
    • Institute for Clinical Evaluative Sciences
      Toronto, Ontario, Canada
    • University of Western Australia
      • School of Population Health
      Perth City, Western Australia, Australia
  • 2005–2014
    • Sunnybrook Health Sciences Centre
      • • Division of Cardiology
      • • Department of Medicine
      Toronto, Ontario, Canada
    • The Toronto Centre for Phenogenomics
      Toronto, Ontario, Canada
  • 2004–2014
    • University of Toronto
      • • Division of Cardiac Surgery
      • • Division of Cardiology
      • • Institute for Clinical Evaluative Sciences
      Toronto, Ontario, Canada
  • 2011
    • The University of Chicago Medical Center
      Chicago, Illinois, United States
    • Western University of Health Sciences
      • College of Pharmacy
      Pomona, CA, United States
  • 2010
    • Icahn School of Medicine at Mount Sinai
      Manhattan, New York, United States
  • 2006–2010
    • McMaster University
      • Department of Pathology and Molecular Medicine
      Hamilton, Ontario, Canada
  • 2008
    • University Health Network
      Toronto, Ontario, Canada
  • 2002–2007
    • Yale University
      • Section of Cardiovascular Medicine
      New Haven, CT, United States
  • 2004–2005
    • Children's Heart Center
      Las Vegas, Nevada, United States
  • 2002–2004
    • Yale-New Haven Hospital
      • Department of Laboratory Medicine
      New Haven, Connecticut, United States