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Yusuf S. Anti-ischaemic effects of ACE inhibitors: review of current clinical evidence and ongoing clinical trials. Eur Heart J 1998. [DOI: 10.1053/euhj.1998.1378] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Anand SS, Yusuf S, Vuksan V, Devanesen S, Montague P, Kelemen L, Bosch J, Sigouin C, Teo KK, Lonn E, Gerstein HC, Hegele RA, McQueen M. The Study of Health Assessment and Risk in Ethnic groups (SHARE): rationale and design. The SHARE Investigators. Can J Cardiol 1998; 14:1349-57. [PMID: 9854515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
The Study of Health Assessment and Risk in Ethnic groups (SHARE) is a study to determine the risk factors for atherosclerosis among three ethnic populations in Canada. Three hundred and thirty South Asian Canadian, 320 Chinese Canadian and 320 European Canadian men and women between 35 and 75 years of age are being randomly sampled from communities in Hamilton and Toronto, Ontario and Edmonton, Alberta for assessment of conventional (i.e., smoking, dyslipidemia, diabetes and hypertension) and emerging (i.e., candidate genes for atherosclerosis, homocysteine, fibrinolytic parameters, neurohormones, glucose intolerance, markers of infection, socioeconomic status, psychosocial status and diet) cardiovascular disease risk factors. Subclinical atherosclerosis is measured by quantitative B-mode ultrasonography of the carotid arteries, and other objective measures of vascular disease are a 12-lead electrocardiogram, a two-dimensional echocardiogram, ankle to arm blood pressure ratio and urine microalbumin concentration. The relationship between the conventional and emerging risk factors, and atherosclerosis, vascular disease and markers of end-organ damage will be evaluated between and within ethnic groups.
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Anand SS, Yusuf S, Pogue J, Weitz JI, Flather M. Long-term oral anticoagulant therapy in patients with unstable angina or suspected non-Q-wave myocardial infarction: organization to assess strategies for ischemic syndromes (OASIS) pilot study results. Circulation 1998; 98:1064-70. [PMID: 9736592 DOI: 10.1161/01.cir.98.11.1064] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Patients with acute ischemic syndromes (AIS) suffer high rates of recurrent ischemic events despite aspirin treatment. Long-term therapy with oral anticoagulants in addition to aspirin may reduce this risk. We studied the effects of long-term warfarin at 2 intensities in patients with AIS without ST elevation in 2 consecutive randomized controlled studies. METHODS AND RESULTS In phase 1, after the cessation of 3 days of intravenous antithrombotic therapy, 309 patients were randomized to receive fixed low-dose (3 mg/d) warfarin for 6 months that produced a mean international normalized ratio (INR) of 1.5+/-0.6 or to standard therapy. Eighty-seven percent of patients received aspirin in both groups. The rates of cardiovascular (CV) death, new myocardial infarction (MI), and refractory angina at 6 months were 6.5% in the warfarin group and 3.9% in the standard therapy group (relative risk [RR], 1. 66; 95% CI, 0.62 to 4.44; P=0.31). The rates of death, new MI, and stroke were 6.5% in the warfarin group and 2.6% in the standard therapy group (RR, 2.48; 95% CI, 0.80 to 7.75; P=0.10). The overall rate of rehospitalization for unstable angina was 21% and did not differ significantly between the groups. Four patients in the warfarin group (2.6%) and none in the control group experienced a major bleed (RR, 2.48; 95% CI, 0.80 to 7.75), and there was a significant excess of minor bleeds in the warfarin group (14.2% versus 2.6%; RR, 5.46; 95% CI, 1.93 to 15.5; P=0.001). In phase 2, the protocol was modified, and 197 patients were randomized <48 hours from the onset of symptoms to receive warfarin at an adjusted dose that produced a mean INR of 2.3+/-0.6 or standard therapy for 3 months. Eighty-five percent received aspirin in both groups. The rates of CV death, new MI, and refractory angina at 3 months were 5. 1% in the warfarin group and 12.1% in the standard group (RR, 0.42; 95% CI, 0.15 to 1.15; P=0.08). The rates of all death, new MI, and stroke were 5.1% in the warfarin group and 13.1% in the standard therapy group (RR, 0.39; 95% CI, 0.14 to 1.05; P=0.05). Significantly fewer patients were rehospitalized for unstable angina in the warfarin group than in the control group (7.1% and 17.2%, respectively; RR, 0.42; 95% CI, 0.18 to 0.96; P=0.03). Two patients in the warfarin group and 1 in the control group experienced a major bleed, and there was a significant excess of minor bleeds in the warfarin group (28.6% versus 12.1%; RR, 2.36; 95% CI, 1.37 to 4.36; P=0.004). CONCLUSIONS Long-term treatment with moderate-intensity warfarin (INR, 2.0 to 2.5) plus aspirin but not low-intensity warfarin (INR, 1.5) plus aspirin appears to reduce the rate of recurrent ischemic events in patients with AIS without ST elevation.
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Yusuf S, Lonn E. Anti-ischaemic effects of ACE inhibitors: review of current clinical evidence and ongoing clinical trials. Eur Heart J 1998; 19 Suppl J:J36-44. [PMID: 9796839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Important ongoing experimental and clinical research is evaluating the potential use of ACE inhibitors in a wider range of patients, in addition to their well accepted use in heart failure, left ventricular dysfunction and hypertension. We review briefly the clinical data supporting a potential role for ACE inhibitors in the prevention of myocardial infarction and stroke and the wider use of these agents in hypertension, renal disease and diabetes. We also briefly review the major ongoing trials evaluating these hypotheses.
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Kronenberg MW, Konstam MA, Edens TR, Howe DM, Dolan N, Udelson JE, Benedict C, Stewart D, Yusuf S. Factors influencing exercise performance in patients with left ventricular dysfunction. SOLVD Investigators. Studies of Left Ventricular Dysfunction. J Card Fail 1998; 4:159-67. [PMID: 9754586 DOI: 10.1016/s1071-9164(98)80002-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND The determinants of exercise performance are multifactorial and incompletely understood in patients with symptomatic left ventricular (LV) dysfunction, with much less information regarding asymptomatic LV dysfunction. This study assessed the hemodynamics and neurohormonal factors influencing exercise performance in patients with LV ejection fractions > or =0.35, both symptomatic and asymptomatic, enrolled in Studies of LV Dysfunction. METHODS AND RESULTS We studied 103 patients enrolled prospectively in Studies of LV Dysfunction before randomized therapy; 38 were symptomatic and 65 had no or minimal symptoms. By using rest-exercise gated equilibrium radionuclide ventriculography and cuff blood pressure, we assessed the heart rate, LV and right ventricular (RV) volumes and ejection fractions, total peripheral resistance, the LV peak systolic pressure/end systolic volume ratio as an index of contractility, and plasma renin and norepinephrine at rest and during maximal graded supine bicycle ergometer exercise. Changes between rest and exercise were evaluated as indices of cardiovascular reserve. The cumulative workload ranged from 120 to 2,100 watt-min. At rest, the LV ejection fraction was 0.30 in asymptomatic patients and 0.25 in symptomatic patients, respectively (P < .0004). During exercise, asymptomatic patients had greater increases in heart rate, systolic blood pressure, LV ejection fraction, and cardiac output than symptomatic patients (P > or = .05). Combining all patients, the strongest univariate correlates of exercise workload were the ability to increase heart rate (r = 0.70), the pressure/volume ratio (r = 0.63), and systolic blood pressure (r = 0.55), and to decrease the total peripheral resistance (r = -0.47) with moderate correlations for the ability to increase LV and RV ejection fractions (r = 0.33 and 0.35, respectively) (P < .0008). By multivariate analysis, workload was modeled best by the changes in four factors: heart rate, systolic blood pressure, and the LV and RV ejection fractions (R2 = 0.54, P < .001). CONCLUSION Exercise performance and its hemodynamics differed in patients with symptomatic and asymptomatic LV dysfunction. Rather than features at rest, the reserve capacities for increasing heart rate, systolic blood pressure, and the LV and RV ejection fractions were the predominant cardiac mechanisms related to greater exercise performance.
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Kitching AD, Yusuf S. Primary coronary angioplasty is superior to thrombolytic therapy for acute MI. EVIDENCE-BASED CARDIOVASCULAR MEDICINE 1998; 2:81. [PMID: 16379837 DOI: 10.1016/s1361-2611(98)80074-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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Yusuf S, Flather M, Pogue J, Hunt D, Varigos J, Piegas L, Avezum A, Anderson J, Keltai M, Budaj A, Fox K, Ceremuzynski L. Variations between countries in invasive cardiac procedures and outcomes in patients with suspected unstable angina or myocardial infarction without initial ST elevation. OASIS (Organisation to Assess Strategies for Ischaemic Syndromes) Registry Investigators. Lancet 1998; 352:507-14. [PMID: 9716054 DOI: 10.1016/s0140-6736(97)11162-x] [Citation(s) in RCA: 240] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND There are wide variations between countries in the use of invasive cardiac catheterisation and revascularisation procedures for patients with acute ischaemic syndromes. We studied the relation between rates of such procedures and rates of cardiovascular death, myocardial infarction, stroke, refractory angina, and major bleeding in a prospective, registry-based study in six countries with widely varying intervention rates. METHODS 7987 consecutive patients presenting with unstable angina or suspected myocardial infarction without ST-segment elevation were recruited prospectively from 95 hospitals in six countries and followed up for 6 months. FINDINGS The rates of all procedures were highest in patients in Brazil and the USA, intermediate in Canada and Australia, and lowest in Hungary and Poland. There were no significant differences in rates of cardiovascular death or myocardial infarction among these countries (4.7% overall [range 3.7-5.6] at 7 days; 11% overall [9-12] at 6 months). For the countries with the highest rates of invasive procedures (59%) versus the rest (21%) there was no difference in rate of cardiovascular death or myocardial infarction (adjusted odds ratio 0.88 at 7 days and 1.0 at 6 months). Rates of stroke were higher in Brazil and the USA than in the countries with lower intervention rates (adjusted odds ratio at 7 days 3.0, p=0.012; at 6 months 1.8, p=0.004) but rates of refractory angina at 7 days (0.7, p<0.001) and readmission for unstable angina at 6 months were lower (0.70, 0.63; both p<0.001). Comparison of results for hospitals without cardiac-catheterisation facilities and for those with such facilities gave adjusted odds ratios for cardiovascular death, myocardial infarction, or stroke at 6 months of 0.83 (10.6% vs 12.5%, p=0.05) and for refractory angina of 1.25 (19.3% vs 16.1%, p=0.09). INTERPRETATION Higher rates of invasive and revascularisation procedures were associated with lower rates of refractory angina or readmission for unstable angina, no apparent reduction in cardiovascular death or myocardial infarction, but with higher rates of stroke. Randomised trials should assess the relative impact of conservative and more aggressive approaches to invasive cardiac procedures and revascularisations in patients with unstable angina.
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Avezum A, Tsuyuki RT, Pogue J, Yusuf S. Beta-blocker therapy for congestive heart failure: a systemic overview and critical appraisal of the published trials. Can J Cardiol 1998; 14:1045-53. [PMID: 9738164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE To evaluate the effect of beta-blockers on mortality and morbidity, and to provide an appraisal of the reliability of the available data. DATA SOURCES MEDLINE search for trials of beta-blockers for congestive heart failure (CHF). STUDY SELECTION All randomized trials of beta-blockers versus placebo, or greater than one month's duration, in patients with CHF. Eighteen published trials involving 2986 patients were selected. DATA EXTRACTION Independently by two authors. DATA SYNTHESIS The Yusuf-Peto method for combining data was used. Data were available on mortality in 2841 patients (95%), on hospitalization for heart failure in 1514 (51%) and on heart transplantation in 2330 (79%). There was a lower rate of death in the active treatment group (131 of 1606) [8.2] versus 155 of 1235 [12.6%]; OR = 72; 99% CI 0.51 to 1.00), a lower rate of hospitalization for heart failure (137 of 756 [18.1%] versus 218 of 758 [28.7%]; OR = 0.54; 99% CI 0.39 to 0.74) and a trend towards a lower proportion of patients receiving heart transplantation (15 of 1354 [l.1%] versus 26 of 976 [2.7%]; OR = 0.45; 99% CI 0.20 to 1.03). Ventricular function improved; however, there was no effect on exercise duration. Although the effects on mortality were nominally statistically significant, the use of formal methods of interim monitoring adapted for meta-analyses suggests that substantially more patients still need to be studied in large scales trials to provide reliable and conclusive evidence. CONCLUSIONS While the available data on the use of beta-blockers in CHF appear to be promising, they are neither complete nor robust. The routine use of beta-blockers in patients with heart failure should wait the results of ongoing studies.
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Yusuf S. The global problem of cardiovascular disease. INTERNATIONAL JOURNAL OF CLINICAL PRACTICE. SUPPLEMENT 1998; 94:3-6. [PMID: 9926439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The greatest cause of death throughout the world today is noncommunicable disease. In Western societies, coronary artery disease is a principal cause of death. In developing countries, the incidence of coronary disease is rising as well. Heart disease often occurs in younger persons in developing societies, resulting in a disproportionately greater number of years of life lost. The reason for this change in global patterns of mortality is that deaths from infectious diseases are declining, resulting in greater life expectancy and changing lifestyles.
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Lonn EM, Yusuf S. Emerging approaches in the prevention of atherosclerotic cardiovascular diseases. INTERNATIONAL JOURNAL OF CLINICAL PRACTICE. SUPPLEMENT 1998; 94:7-19. [PMID: 9926440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
This presentation reviews data from epidemiologic and clinical trials on antioxidant vitamins, angiotensin-converting enzyme inhibitors, and homocysteine and their effect on atherosclerotic cardiovascular disease. Each of these areas seems promising, but the results of large, on-going studies must be determined before definitive conclusions can be made as to the effectiveness of these therapies.
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Anand SS, Enas EA, Pogue J, Haffner S, Pearson T, Yusuf S. Elevated lipoprotein(a) levels in South Asians in North America. Metabolism 1998; 47:182-4. [PMID: 9472967 DOI: 10.1016/s0026-0495(98)90217-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
This report demonstrates that South Asians living in North America have elevated levels of Lp(a) compared with North American whites. Elevated Lp(a) levels may account, in part, for the tendency of South Asians to develop premature coronary heart disease (CHD).
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Chareonthaitawee P, Gibbons R, Roberts R, Christian T, Burns R, Yusuf S. The impact of time to thrombolytic therapy on outcome in patients with acute myocardial infarction (AMI). J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)80317-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
For a meta-analysis to give definitive information, it should meet at least the minimum standards that would be expected of a well-designed, adequately powered, and carefully conducted randomised controlled trial. These minimum standards include both qualitative characteristics--a prospective protocol, comparable definitions of key outcomes, quality control of data, and inclusion of all patients from all trials in the final analysis--and quantitative standards--an assessment of whether the total sample is large enough to provide reliable results and the use of appropriate statistical monitoring guidelines to indicate when the results of the accumulating data of a meta-analysis are conclusive. We believe that rigorous meta-analyses undertaken according to these principles will lead to more reliable evidence about the efficacy and safety of interventions than either retrospective meta-analysis or individual trials.
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Suskin N, McKelvie R, Rouleau J, Sigoun C, Wiecek E, Yusuf S. Increased insulin and glucose levels in heart failure (HF). J Am Coll Cardiol 1998. [DOI: 10.1016/s0735-1097(98)81722-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Enas EA, Yusuf S, Sharma S. Coronary artery disease in South Asians. Second meeting of the International Working Group. 16 March 1997, Anaheim, California. Indian Heart J 1998; 50:105-13. [PMID: 9583302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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Yusuf S, Pogue J. Primary angioplasty compared with thrombolytic therapy for acute myocardial infarction. JAMA 1997; 278:2110-1. [PMID: 9403429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Pogue JM, Yusuf S. Cumulating evidence from randomized trials: utilizing sequential monitoring boundaries for cumulative meta-analysis. CONTROLLED CLINICAL TRIALS 1997; 18:580-93; discussion 661-6. [PMID: 9408720 DOI: 10.1016/s0197-2456(97)00051-2] [Citation(s) in RCA: 304] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We propose the adaptation of classical monitoring boundaries for use in cumulative meta-analysis as guidelines for deciding when accumulating evidence is statistically significant and medically convincing. The interpretation of information from a randomized controlled trial is compared with that from a meta-analysis. The concept of optimal information size for a meta-analysis is developed and used to adapt monitoring boundaries to cumulative meta-analysis.
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Tsuyuki RT, Yusuf S, Rouleau JL, Maggioni AP, McKelvie RS, Wiecek EM, Wang Y, Pogue J, Teo KK, White M, Avezum A, Latini R, Held P, Lindgren E, Probstfield J. Combination neurohormonal blockade with ACE inhibitors, angiotensin II antagonists and beta-blockers in patients with congestive heart failure: design of the Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) Pilot Study. Can J Cardiol 1997; 13:1166-74. [PMID: 9444298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND The Randomized Evaluation of Strategies for Left Ventricular Dysfunction (RESOLVD) Pilot Study is a trial of combination neurohormonal blockade using an angiotensin II antagonist (candesartan), an angiotensin-converting enzyme inhibitor (enalapril) and a beta-blocker (metoprolol) in patients with congestive heart failure (CHF). OBJECTIVES Primary objectives of stage I are to determine the efficacy (via the 6 min walk test) and safety of candesartan alone, and in combination with enalapril, versus enalapril alone. Secondary objectives are to determine the effect of the above combinations on neurohormones, ventricular function, quality of life and symptoms. Stage II objectives are similar, evaluating the effect of the addition of metoprolol or placebo to the above medication(s). DESIGN Randomized, two-stage trial consisting of a three-way comparison (stage I), followed by a 3 x 2 partial factorial design (stage II). SETTING Sixty out-patient clinics in five countries. PATIENTS Patients with symptoms of CHF (New York Heart Association functional classes II to IV), ejection fraction less than 40% and 6 min walk distance of 500 m or less. INTERVENTIONS In stage I, 770 patients are randomized to receive candesartan alone, enalapril alone, or candesartan plus enalapril. After five months (end of stage I), patients are assessed for eligibility to be randomized in stage II. Those who are not candidates for randomization to beta-blocker or placebo are followed on their stage I medications until the end of the study. In stage II, patients are randomized to receive metoprolol or placebo for a further six months in addition to their stage I medications. Endpoints are measured at baseline, end of stage I (week 20) and end of stage II (week 46). STUDY STATUS: The study has recently completed follow-up in both stages. The findings from this study will be used to design a large scale mortality study that will help further define the role of neurohormonal blockade in patients with CHF.
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Yusuf S. Meta-analysis of randomized trials: looking back and looking ahead. CONTROLLED CLINICAL TRIALS 1997; 18:594-601; discussion 661-6. [PMID: 9408721 DOI: 10.1016/s0197-2456(97)00052-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Meta-analyses as currently practiced are usually retrospective. They can be made more rigorous by developing a protocol that incorporates prospectively the elements that are usually necessary in a well-designed trial. Meta-analysis and large trials are complementary. Meta-analysis of small trials is useful in generating the hypotheses and assisting in the design of the large trials that are needed. Once the large trials have been completed, they could be brought together within the framework of a meta-analysis to estimate the overall treatment effect with greater confidence and to explore the effects in various subgroups. This article explores the value and limitations of meta-analyses and suggests ways of improving their conduct and interpretation.
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Flather MD, Farkouh ME, Pogue JM, Yusuf S. Strengths and limitations of meta-analysis: larger studies may be more reliable. CONTROLLED CLINICAL TRIALS 1997; 18:568-79; discussion 661-6. [PMID: 9408719 DOI: 10.1016/s0197-2456(97)00024-x] [Citation(s) in RCA: 156] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Meta-analysis of randomized controlled trials combines information from independent studies that address a similar question to provide more reliable estimates of treatment effects. At the present time, the methodology and usefulness of meta-analysis is under scrutiny. In the first part of this paper, we summarize the limitations of meta-analysis and make suggestions for improvements. In the second part, we illustrate strengths and limitations using examples of meta-analyses and subsequent large trials that address the same question. We develop the hypothesis that the size of the meta-analysis may be a useful measure of reliability. Small meta-analyses (i.e., those with less than 200 outcome events) may only be useful for summarizing the available information and generating hypotheses for future research. The results of small meta-analyses should be regarded with caution, even if the p value shows extreme statistical significance. Larger meta-analyses (i.e., those with several hundred events) are likely to be more reliable and may be clinically useful. Well-conducted meta-analyses of large trials using individual patient data may provide the best estimates of treatment effects in the cohort overall and in clinically important subgroups.
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Yusuf S, Kitching AD. From journal to bedside: obtaining medically useful answers from a meta-analysis. EVIDENCE-BASED CARDIOVASCULAR MEDICINE 1997; 1:85-6. [PMID: 16379745 DOI: 10.1016/s1361-2611(97)80001-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
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Yusuf S. Digoxin in heart failure: results of the recent Digoxin Investigation Group trial in the context of other treatments for heart failure. Eur Heart J 1997; 18:1685-8. [PMID: 9402436 DOI: 10.1093/oxfordjournals.eurheartj.a015156] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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