Gordon H Guyatt

Gordon H Guyatt
McMaster University | McMaster · heath research methods, evidence, and impact

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1,405
Publications
315,638
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Publications

Publications (1,405)
Article
Full-text available
Introduction: Methodological studies (ie, studies that evaluate the design, conduct, analysis or reporting of other studies in health research) address various facets of health research including, for instance, data collection techniques, differences in approaches to analyses, reporting quality, adherence to guidelines or publication bias. As a res...
Article
Background: Hip fractures are a leading cause of disability worldwide, with displaced femoral neck fractures being of particular concern. A recent meta-analysis reported that total hip arthroplasty (THA) was superior to hemiarthroplasty (HA) in terms of reoperations, but inferior in terms of dislocations. However, publication of 4 additional random...
Article
This article has been corrected. The original version (PDF) is appended to this article as a Supplement. Background: Dietary guidelines generally recommend limiting intake of red and processed meat. However, the quality of evidence implicating red and processed meat in adverse health outcomes remains unclear. Purpose: To evaluate the associatio...
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Background: Studying dietary patterns may provide insights into the potential effects of red and processed meat on health outcomes. Purpose: To evaluate the effect of dietary patterns, including different amounts of red or processed meat, on all-cause mortality, cardiometabolic outcomes, and cancer incidence and mortality. Data Sources: Systemati...
Article
Background: Few randomized trials have evaluated the effect of reducing red meat intake on clinically important outcomes. Purpose: To summarize the effect of lower versus higher red meat intake on the incidence of cardiometabolic and cancer outcomes in adults. Data Sources: EMBASE, CENTRAL, CINAHL, Web of Science, and ProQuest from inception to J...
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Background Many interventions have shown effectiveness in reducing the duration of acute diarrhea and gastroenteritis (ADG) in children. Yet, there is lack of comparative efficacy of interventions that seem to be better than placebo among which, the clinicians must choose. Our aim was to determine the comparative effectiveness and safety of the pha...
Article
IMPORTANCE Progression-free survival (PFS) has become a commonly used outcome to assess the efficacy of new cancer drugs. However, it is not clear if delay in progression leads to improved quality of life with or without overall survival benefit. OBJECTIVE To evaluate the association between PFS and health-related quality of life (HRQoL) in oncolo...
Article
Background: Trustworthy clinical practice guidelines (CPGs) require identification and careful management of conflicts of interest (COIs) among all participants in the guideline development. Furthermore, COIs are more common than anticipated. However, there are no universally accepted methods to identify and manage COIs. Objective: To describe a...
Article
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What is the role of prostate-specific antigen (PSA) screening in prostate cancer? An expert panel produced these recommendations based on a linked systematic review. The review was triggered by a large scale, cluster randomised trial on PSA screening in men without a previous diagnosis of prostate cancer published in 2018. It found no difference be...
Article
When direct and indirect estimates of treatment effects are coherent, network meta-analysis (NMA) estimates should have increased precision (narrower confidence or credible intervals compared with relying on direct estimates alone), a benefit of NMA. We have, however, observed cases of sparse networks in which combining direct and indirect estimate...
Article
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Background: Public health journals need to have clear policies for reporting the funding of studies and authors’ personal financial and non-financial conflicts of interest (COI) disclosures. This study aims to assess the policies of public health journals on reporting of study funding and the disclosure of authors’ COIs. Methods: This is a cross-s...
Article
Objective: To describe how systematic review authors report and address categories of participants with potential missing outcome data of trial participants. Study design: Methodological survey of systematic reviews reporting a group-level meta-analysis. Results: We included a random sample of 50 Cochrane and 50 non-Cochrane systematic reviews...
Article
Background: Evidence-based clinical practice guidelines provide recommendations to assist clinicians in decision-making and to reduce the gap between best current research evidence and clinical practice. However, some argue that providing pre-appraised evidence summaries alone, rather than recommendations, is more appropriate. Objectives: To eva...
Article
In Reply Drs Leening and Pencina discourage the use of absolute NRI when comparing the performance of 2 predictive models by stating that “the absolute NRI is mathematically improper and has no clinical interpretation.” They also argue that the absolute NRI does not consider the prevalence of the event of interest. These arguments are incorrect and...
Article
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What role do antibiotics have in the treatment of uncomplicated skin abscesses after incision and drainage? A recent study suggested that, for small uncomplicated skin abscesses, antibiotics after incision and drainage improve the chance of short term cure compared with placebo. Triggered by this trial, the Rapid Recommendation team produced a new...
Article
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Background: Worldwide approximately 200 million adults undergo major surgery annually, of whom 8 million are estimated to suffer a myocardial injury after noncardiac surgery (MINS). There is currently no trial data informing the management of MINS. Antithrombotic agents such as direct oral anticoagulants might prevent major vascular complications...
Article
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Objective To assess the impact of adjunctive antibiotic therapy on uncomplicated skin abscesses. Design Systematic review and network meta-analysis. Data sources Medline, Embase, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov. Study selection A BMJ Rapid Recommendation panel provided input on design, important outcomes...
Article
Objective: To provide guidance on how systematic review authors, guideline developers, and health technology assessment practitioners should approach the use of the risk of bias in non-randomized studies of interventions (ROBINS-I) tool as part of GRADE's certainty rating process. Study design and setting: Iterative discussions, testing in syste...
Article
Objective: The GRADE working group defines patient values and preferences as the relative importance patients place on the main health outcomes. We provide GRADE guidance for assessing the risk of bias and indirectness domains for certainty of evidence about the relative importance of outcomes. Study design and setting: We applied the GRADE doma...
Article
Objectives: To review the literature and obtain preferences and perceptions from experts regarding the role of randomized studies (RS) and non-randomized studies (NRS) in systematic reviews of intervention effects. Study design and setting: Scoping review and survey of experts. Using levels of certainty developed by the Grading of Recommendation...
Article
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Laboratory animal studies are used in a wide range of human health related research areas, such as basic biomedical research, drug research, experimental surgery and environmental health. The results of these studies can be used to inform decisions regarding clinical research in humans, for example the decision to proceed to clinical trials. If the...
Data
Summary of identified criteria possibly related to certainty in the evidence in the methods and discussion sections of SRs of preclinical animal studies. (XLSX)
Data
Summary of all (unduplicated) criteria possibly related to certainty in the evidence. (XLSX)
Data
Examples of assessing indirectness of evidence from preclinical animal studies. (DOCX)
Data
Summary of identified criteria possibly related to certainty in the evidence resulting from analysis of the paper of Krauth et al. (XLSX)
Data
Main differences between risk of bias of clinical and preclinical animal intervention studies. (DOCX)
Article
Aims: The Fluid Lavage in Open Fracture Wounds (FLOW) trial was a multicentre, blinded, randomized controlled trial that used a 2 × 3 factorial design to evaluate the effect of irrigation solution (soap versus normal saline) and irrigation pressure (very low versus low versus high) on health-related quality of life (HRQL) in patients with open fra...
Article
PurposeGuidelines for shock recommend mean arterial pressure (MAP) targets for vasopressor therapy of at least 65 mmHg and, until recently, suggested that patients with underlying chronic hypertension and atherosclerosis may benefit from higher targets. We conducted an individual patient-data meta-analysis of recent trials to determine if patient v...
Article
Full-text available
Owing to an oversight by the authors, all the figures in the last column of Table 2 (upper section: Number needed to treat; lower section: Number needed to harm) in this article were given without the final digit 0 and are thus 10 times too small.
Conference Paper
Background: Guidelines suggest the use of the Khorana score to select patients with solid cancer receiving chemotherapy for thromboprophylaxis to prevent venous thromboembolism (VTE), but its performance in different types of cancers remains uncertain.
Conference Paper
Background: Parenteral anticoagulants may improve outcomes in patients with cancer by reducing the risk of venous thromboembolism (VTE) and through a direct anti-tumour effect. Study-level meta-analysis indicates a reduction in VTE and provide moderate certainty that a small survival benefit exists; it is unclear if patients with specific cancers b...
Article
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When randomized trials have addressed multiple interventions for the same health problem, network meta-analyses (NMAs) permit researchers to statistically pool data from individual studies including evidence from both direct and indirect comparisons. Grasping the significance of the results of NMAs may be very challenging. Authors may present the f...
Article
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Purpose: Stress ulcer prophylaxis (SUP) is commonly prescribed in the intensive care unit. However, data from systematic reviews and conventional meta-analyses are limited by imprecision and restricted to direct comparisons. We conducted a network meta-analysis of randomized clinical trials (RCTs) to examine the safety and efficacy of drugs availa...
Article
Objective: Shared-care decision-making between patients and clinicians involves making trade-offs between desirable and undesirable consequences of management strategies. Although patient values and preferences should provide the basis for these trade-offs, few guidelines consider the relevant evidence when formulating recommendations. To inform a...
Article
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Background: Uncertainty remains about the effects of aspirin in patients with prior percutaneous coronary intervention (PCI) having noncardiac surgery. Objective: To evaluate benefits and harms of perioperative aspirin in patients with prior PCI. Design: Nonprespecified subgroup analysis of a multicenter factorial trial. Computerized Internet...
Article
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Introduction UpToDate is widely used by clinicians worldwide and includes more than 9400 recommendations that apply the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework. GRADE guidance warns against strong recommendations when certainty of the evidence is low or very low (discordant recommendations) but has identi...
Article
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Objectives Current guidelines suggest limiting the use of vasopressors following traumatic injury; however, wide variations in practice exist. Although excessive vasoconstriction may be harmful, these agents may help reduce administration of potentially harmful resuscitation fluids. This systematic review aims to compare early vasopressor use to st...
Article
Background: Prognostic evaluation in heart failure (HF) is important to predict future events and decide timely management. Many HF patients are treated with an implantable cardioverter defibrillator (ICD). This study aimed to validate a meta-analytically-derived prognostic score to predict survival in ICD-HF patients. Methods and results: The H...
Article
Severe life-threatening dengue fever usually occurs when a child is infected by dengue virus a 2nd time. This is caused by a phenomenon called antibody dependent enhancement or ADE. Since dengue vaccines can mimic a first infection in seronegative children (those with no previous infection), a natural infection later in life could lead to severe di...
Article
Accurate information regarding prognosis is fundamental to optimal clinical care. The best approach to assess patient prognosis relies on prediction models that simultaneously consider a number of prognostic factors and provide an estimate of patients’ absolute risk of an event. Such prediction models should be characterized by adequately discrimin...
Article
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The availability of evidence-based guidelines does not ensure their implementation and use in clinical practice or policy making. Inequities in health have been defined as those inequalities within or between populations that are avoidable, unnecessary and also unjust and unfair. Evidence-based clinical practice and public health guidelines ('guide...
Article
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Objectives To provide a detailed and current characterisation of funding of a representative sample clinical trials. We also aimed to develop guidance for standardised reporting of funding information. Methods We addressed the extent to which clinical trials published in 2015 in any of the 119 Core Clinical Journals included a statement on the fun...
Article
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Daily administration of vitamin D is important for maintaining bone homeostasis. The orthopedic community has shown increased interest in vitamin D supplementation and patient outcomes after fracture. The current study used data from a large hip fracture trial to determine the proportion of patients who consistently used vitamin D after hip fractur...
Article
This article describes conceptual advances of the Grading of Recommendations Assessments, Development, and Evaluation (GRADE) working group guidance to evaluate certainty of evidence (confidence in evidence, quality of evidence) from network meta-analysis (NMA). Application of the original GRADE guidance, published in 2014, in a number of NMAs has...
Article
Full-text available
Introduction Many studies have indicated the impact of bias in dissemination and publication in medical research. Existence of such bias among clinical trials has been repeatedly pointed out, but it has not been well studied in the field of systematic reviews (SRs). We therefore aim to investigate whether or not time lag bias and publication bias i...
Article
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Objective To estimate the benefits and harms of using corticosteroids as an adjunct treatment for sore throat. Design Systematic review and meta-analysis of randomised control trials. Data sources Medline, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), trial registries up to May 2017, reference lists of eligible trials, related...
Data
Appendix 2: Summary of risk of bias assessments among the included trials