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Deborah J. Cook

Bio: Deborah J. Cook is an academic researcher from McMaster University. The author has contributed to research in topics: Intensive care & Intensive care unit. The author has an hindex of 173, co-authored 907 publications receiving 148928 citations. Previous affiliations of Deborah J. Cook include McMaster University Medical Centre & Queen's University.


Papers
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Journal ArticleDOI
TL;DR: Results of several cohort studies suggest that smoking cessation after myocardial infarction is associated with a significant decrease in mortality.
Abstract: Objective To determine the effect of smoking cessation on mortality after myocardial infarction Data Sources English- and non–English-language articles published from 1966 through 1996 retrieved using keyword searches of MEDLINE and EMBASE supplemented by letters to authors and searching bibliographies of reviews Study Selection Selection of relevant abstracts and articles was performed by 2 independent reviewers Articles were chosen that reported the results of cohort studies examining mortality in patients who quit vs continued smoking after myocardial infarction Data Extraction Mortality data were extracted from the selected articles by 2 independent reviewers Data Synthesis Twelve studies were included containing data on 5878 patients The studies took place in 6 countries between 1949 and 1988 Duration of follow-up ranged from 2 to 10 years All studies showed a mortality benefit associated with smoking cessation The combined odds ratio based on a random effects model for death after myocardial infarction in those who quit smoking was 054 (95% confidence interval, 046-062) Relative risk reductions across studies ranged from 15% to 61% The number needed to quit smoking to save 1 life is 13 assuming a mortality rate of 20% in continuing smokers The mortality benefit was consistent regardless of sex, duration of follow-up, study site, and time period Conclusion Results of several cohort studies suggest that smoking cessation after myocardial infarction is associated with a significant decrease in mortality

412 citations

Journal ArticleDOI
06 Jan 2005-BMJ
TL;DR: Evidence is presented to support the argument that increased use of the expertise based design will enhance the validity, applicability, feasibility, and ethical integrity of randomised controlled trials in surgery, as well as in other areas.
Abstract: Surgical procedures are less likely to be rigorously evidence based than drug treatments because of difficulties with randomisation. Expertise based trials could be the way forward Although conventional randomised controlled trials are widely recognised as the most reliable method to evaluate pharmacological interventions,1 2 scepticism about their role in nonpharmacological interventions (such as surgery) remains.3–6 Conventional randomised controlled trials typically randomise participants to one of two intervenions (A or B) and individual clinicians give intervention A to some participants and B to others. An alternative trial design, the expertise based randomised controlled trial, randomises participants to clinicians with expertise in intervention A or clinicians with expertise in intervention B, and the clinicians perform only the procedure they are expert in. We present evidence to support our argument that increased use of the expertise based design will enhance the validity, applicability, feasibility, and ethical integrity of randomised controlled trials in surgery, as well as in other areas. We focus on established surgical interventions rather than new surgical procedures in which clinicians have not established expertise. Investigators have used the expertise based design when conventional randomised controlled trials were impossible because different specialty groups provided the interventions under evaluation—for example, percutaneous transluminal coronary angioplasty versus coronary artery bypass graft surgery.7–9 In 1980, Van der Linden suggested randomising participants to clinicians committed to performing different interventions in an area in which a conventional randomised controlled trial was possible.10 Since that time, however, the expertise based design has been little used, even in areas where it has high potential (such as, surgery, physiotherapy, and chiropractic). ### Differential expertise between procedures Because it takes training and experience to develop expertise in surgical interventions, individual surgeons tend to solely or primarily use a single surgical approach to treat a specific problem.10 11 …

410 citations

Journal ArticleDOI
12 Apr 2007-BMJ
TL;DR: Nitric oxide is associated with limited improvement in oxygenation in patients with ALI or ARDS but confers no mortality benefit and may cause harm.
Abstract: Objective To review the literature on the use of inhaled nitric oxide to treat acute lung injury/acute respiratory distress syndrome (ALI/ARDS) and to summarise the effects of nitric oxide, compared with placebo or usual care without nitric oxide, in adults and children with ALI or ARDS. Design Systematic review and meta-analysis. Data sources Medline, CINAHL, Embase, and CENTRAL (to October 2006), proceedings from four conferences, and additional information from authors of 10 trials. Review methods Two reviewers independently selected parallel group randomised controlled trials comparing nitric oxide with control and extracted data related to study methods, clinical and physiological outcomes, and adverse events. Main outcome measures Mortality, duration of ventilation, oxygenation, pulmonary arterial pressure, adverse events. Results 12 trials randomly assigning 1237 patients met inclusion criteria. Overall methodological quality was good. Using random effects models, we found no significant effect of nitric oxide on hospital mortality (risk ratio 1.10, 95% confidence interval 0.94 to 1.30), duration of ventilation, or ventilator-free days. On day one of treatment, nitric oxide increased the ratio of partial pressure of oxygen to fraction of inspired oxygen (PaO 2 /FiO 2 ratio) (13%, 4% to 23%) and decreased the oxygenation index (14%, 2% to 25%). Some evidence suggested that improvements in oxygenation persisted until day four. There was no effect on mean pulmonary arterial pressure. Patients receiving nitric oxide had an increased risk of developing renal dysfunction (1.50, 1.11 to 2.02). Conclusions Nitric oxide is associated with limited improvement in oxygenation in patients with ALI or ARDS but confers no mortality benefit and may cause harm. We do not recommend its routine use in these severely ill patients.

407 citations

Journal ArticleDOI
TL;DR: This article focuses on the relation between systematic reviews and practice guidelines: how the development of guidelines can benefit from systematic reviews, and how systematic reviews can be used to help implement guidelines.
Abstract: Clinical practice guidelines have been developed to improve the process and outcomes of health care and to optimize resource utilization. By addressing such issues as prevention, diagnosis, and treatment, they can aid in health care decision making at many levels. Several other decision aids are cast in the guideline lexicon, regardless of their focus, formulation, or format; this can foster misunderstanding of the term "guideline." Whether created or adapted locally or nationally, most guidelines are an amalgam of clinical experience, expert opinion, and research evidence. Approaches to practice guideline development vary widely. Given the resources required to identify all relevant primary studies, many guidelines rely on systematic reviews that were either previously published or created de novo by guideline developers. Systematic reviews can aid in guideline development because they involve searching for, selecting, critically appraising, and summarizing the results of primary research. The more rigorous the review methods used and the higher the quality of the primary research that is synthesized, the more evidence-based the practice guideline is likely to be. Summaries of relevant research incorporated into guideline documents can help to keep practitioners up to date with the literature. Systematic reviews have also been published on the dissemination and implementation strategies most likely to change clinician behavior and improve patient outcomes. These can be useful in more effectively translating research evidence into practice.

405 citations

Journal ArticleDOI
TL;DR: The strongest determinants of the withdrawal of ventilation in critically ill patients were the physician's perception that the patient preferred not to use life support, the physicians' predictions of a low likelihood of survival in the intensive care unit and a high likelihood of poor cognitive function, and the use of inotropes or vasopressors.
Abstract: Background In critically ill patients who are receiving mechanical ventilation, the factors associated with physicians' decisions to withdraw ventilation in anticipation of death are unclear. The objective of this study was to examine the clinical determinants that were associated with the withdrawal of mechanical ventilation. Methods We studied adults who were receiving mechanical ventilation in 15 intensive care units, recording base-line physiological characteristics, daily Multiple Organ Dysfunction Scores, the patient's decision-making ability, the type of life support administered, the use of do-not-resuscitate orders, the physician's prediction of the patient's status, and the physician's perceptions of the patient's preferences about the use of life support. We examined the relation between these factors and withdrawal of mechanical ventilation, using Cox proportional-hazards regression analysis. Results Of 851 patients who were receiving mechanical ventilation, 539 (63.3 percent) were successfully weaned, 146 (17.2 percent) died while receiving mechanical ventilation, and 166 (19.5 percent) had mechanical ventilation withdrawn. The need for inotropes or vasopressors was associated with withdrawal of the ventilator (hazard ratio, 1.78; 95 percent confidence interval, 1.20 to 2.66; P=0.004), as were the physician's prediction that the patient's likelihood of survival in the intensive care unit was less than 10 percent (hazard ratio, 3.49; 95 percent confidence interval, 1.39 to 8.79; P=0.002), the physician's prediction that future cognitive function would be severely impaired (hazard ratio, 2.51; 95 percent confidence interval, 1.28 to 4.94; P=0.04), and the physician's perception that the patient did not want life support used (hazard ratio, 4.19; 95 percent confidence interval, 2.57 to 6.81; P Conclusions Rather than age or the severity of the illness and organ dysfunction, the strongest determinants of the withdrawal of ventilation in critically ill patients were the physician's perception that the patient preferred not to use life support, the physician's predictions of a low likelihood of survival in the intensive care unit and a high likelihood of poor cognitive function, and the use of inotropes or vasopressors.

404 citations


Cited by
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Journal ArticleDOI
TL;DR: Moher et al. as mentioned in this paper introduce PRISMA, an update of the QUOROM guidelines for reporting systematic reviews and meta-analyses, which is used in this paper.
Abstract: David Moher and colleagues introduce PRISMA, an update of the QUOROM guidelines for reporting systematic reviews and meta-analyses

62,157 citations

Journal Article
TL;DR: The QUOROM Statement (QUality Of Reporting Of Meta-analyses) as mentioned in this paper was developed to address the suboptimal reporting of systematic reviews and meta-analysis of randomized controlled trials.
Abstract: Systematic reviews and meta-analyses have become increasingly important in health care. Clinicians read them to keep up to date with their field,1,2 and they are often used as a starting point for developing clinical practice guidelines. Granting agencies may require a systematic review to ensure there is justification for further research,3 and some health care journals are moving in this direction.4 As with all research, the value of a systematic review depends on what was done, what was found, and the clarity of reporting. As with other publications, the reporting quality of systematic reviews varies, limiting readers' ability to assess the strengths and weaknesses of those reviews. Several early studies evaluated the quality of review reports. In 1987, Mulrow examined 50 review articles published in 4 leading medical journals in 1985 and 1986 and found that none met all 8 explicit scientific criteria, such as a quality assessment of included studies.5 In 1987, Sacks and colleagues6 evaluated the adequacy of reporting of 83 meta-analyses on 23 characteristics in 6 domains. Reporting was generally poor; between 1 and 14 characteristics were adequately reported (mean = 7.7; standard deviation = 2.7). A 1996 update of this study found little improvement.7 In 1996, to address the suboptimal reporting of meta-analyses, an international group developed a guidance called the QUOROM Statement (QUality Of Reporting Of Meta-analyses), which focused on the reporting of meta-analyses of randomized controlled trials.8 In this article, we summarize a revision of these guidelines, renamed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses), which have been updated to address several conceptual and practical advances in the science of systematic reviews (Box 1). Box 1 Conceptual issues in the evolution from QUOROM to PRISMA

46,935 citations

Journal ArticleDOI
04 Sep 2003-BMJ
TL;DR: A new quantity is developed, I 2, which the authors believe gives a better measure of the consistency between trials in a meta-analysis, which is susceptible to the number of trials included in the meta- analysis.
Abstract: Cochrane Reviews have recently started including the quantity I 2 to help readers assess the consistency of the results of studies in meta-analyses. What does this new quantity mean, and why is assessment of heterogeneity so important to clinical practice? Systematic reviews and meta-analyses can provide convincing and reliable evidence relevant to many aspects of medicine and health care.1 Their value is especially clear when the results of the studies they include show clinically important effects of similar magnitude. However, the conclusions are less clear when the included studies have differing results. In an attempt to establish whether studies are consistent, reports of meta-analyses commonly present a statistical test of heterogeneity. The test seeks to determine whether there are genuine differences underlying the results of the studies (heterogeneity), or whether the variation in findings is compatible with chance alone (homogeneity). However, the test is susceptible to the number of trials included in the meta-analysis. We have developed a new quantity, I 2, which we believe gives a better measure of the consistency between trials in a meta-analysis. Assessment of the consistency of effects across studies is an essential part of meta-analysis. Unless we know how consistent the results of studies are, we cannot determine the generalisability of the findings of the meta-analysis. Indeed, several hierarchical systems for grading evidence state that the results of studies must be consistent or homogeneous to obtain the highest grading.2–4 Tests for heterogeneity are commonly used to decide on methods for combining studies and for concluding consistency or inconsistency of findings.5 6 But what does the test achieve in practice, and how should the resulting P values be interpreted? A test for heterogeneity examines the null hypothesis that all studies are evaluating the same effect. The usual test statistic …

45,105 citations

Journal ArticleDOI
TL;DR: A structured summary is provided including, as applicable, background, objectives, data sources, study eligibility criteria, participants, interventions, study appraisal and synthesis methods, results, limitations, conclusions and implications of key findings.

31,379 citations