Gordon H. Guyatt

Bio: Gordon H. Guyatt is an academic researcher from McMaster University. The author has contributed to research in topics: Randomized controlled trial & Evidence-based medicine. The author has an hindex of 231, co-authored 1620 publications receiving 228631 citations. Previous affiliations of Gordon H. Guyatt include Memorial Sloan Kettering Cancer Center & Cayetano Heredia University.

The core content of a generalist curriculum for general internal medicine, family practice, and pediatrics.

Abstract: The authors analyzed the educational content of the curricula developed for teaching in the generalist disciplines of pediatrics, family medicine, and general internal medicine. Fifteen educational components that constitute the core content shared by the three generalist disciplines are identified, described, and referenced. Tailoring the generalist curriculum for students and residents at the different stages of learning is reviewed, along with the refinement of the curriculum to meet the special needs of each generalist discipline. The success of a generalist curriculum will ultimately be measured by generalist career choices, quality of care, and both patient and professional satisfaction. The curricular determinants of success require institutional commitment to an educational philosophy that embraces the generalist disciplines, a core curriculum that provides education and training that are correlated with the demands of clinical practice, and generalist faculty who serve as role models, mentors, and teachers.

Aqueous beclomethasone dipropionate nasal spray in the treatment of seasonal (ragweed) rhinitis.

Abstract: OBJECTIVES: To determine whether the provision of appropriate medication and comprehensive information before the ragweed pollen season enables patients to manage their hay fever successfully, achieving satisfactory symptom control and quality of life, to examine patient characteristics that may predict successful symptom management and to learn which factors patients consider when making treatment choices. DESIGN: Single-group prospective cohort management study. SUBJECTS: Ninety adults sensitive to ragweed pollen recruited from those who had participated in previous clinical studies and from those who responded to advertisements in the local media. INTERVENTION: Aqueous beclomethasone dipropionate nasal spray and comprehensive information about optimal therapy (starting before the ragweed pollen season and continued throughout at a dose of 400 micrograms/d) and how it may be used less intensively with an as-required regimen. MAIN OUTCOME MEASURES: Symptom control, patient satisfaction, quality of life and medication use. RESULTS: More than 80% of the patients reported very good symptom control and were very satisfied. In all, 62% chose to use less than the optimal daily dose. Patients who had less than optimal symptom control used significantly less of the nasal spray than those with very good control either because they wanted to keep medication use to a minimum or because they were unable to remember to take their medication. The only significant predictor of inadequate control was an acknowledged inability to remember to take medication. Symptoms and trust in the practitioner were the primary factors perceived by the patients to determine their treatment choices. CONCLUSION: When provided with aqueous beclomethasone dipropionate nasal spray and comprehensive information on the drug and dosing, most patients are successful in managing their hay fever.

Health-Related Quality of Life and Participation in Osteoporosis Clinical Trials

Abstract: Although osteoporosis affects millions of elderly women, the quality of their lives is extremely complex and is only recently being appreciated. We recently used a disease-specific Osteoporosis Quality of Life questionnaire (OQLQ) to measure quality of life for 105 elderly osteoporotic women, and reported that by path analysis, spinal fractures, health perception, and several sociodemographic factors accounted for 63% of the variance in quality of life. On the other hand, bone density, Colles fracture, hip fractures, pharmacologic agents, exercise, and several sociodemographic variables were not significant factors. Of particular note was the positive, indirect effect (via health perception and spinal fractures) that participation in a clinical trial (17.5% of the patients) had on life quality. In order to determine how involvement in a research study might affect health perception in this same cohort we examined OQLQ scores in the five domains of the OQLQ for the 18 postmenopausal osteoporotic women enrolled in two different phase III clinical trials with oral bisphosphonates and 87 osteoporotic women treated conventionally (estrogen, bisphosphonate, calcitonin, calcium/vitamin D) in our metabolic bone clinic. Research and clinical patients did not differ in age, femoral BMD, or number of spinal fractures. However, women in research trials had significantly greater aggregate OQLQ scores (5.67 versus 4.23, P < 0.0001) and perceived health (7.28 versus 5.85, P= 0.001) than clinical patients. These differences were highly significant (P < 0.001) for domains of quality of life including physical function, activities of daily living, symptoms, and leisure/social activity and marginally significant for the emotional function domain (P= 0.05). Hence, by regression-based path analysis and subgroup analysis of cross-sectional data, participation in a clinical trial had a significant and positive impact on health-related quality of life. If these findings are confirmed by other studies, identifying those factors inherent in clinical studies that positively impact the lives of osteoporotic patients should become as important a priority as development of new therapies for this chronic disease.

Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement

Abstract: David Moher and colleagues introduce PRISMA, an update of the QUOROM guidelines for reporting systematic reviews and meta-analyses

Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement.

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

Measuring inconsistency in meta-analyses

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 …

Bias in meta-analysis detected by a simple, graphical test

Abstract: Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews . Main outcome measure: Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. Results: In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. Conclusions: A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution. Key messages Systematic reviews of randomised trials are the best strategy for appraising evidence; however, the findings of some meta-analyses were later contradicted by large trials Funnel plots, plots of the trials9 effect estimates against sample size, are skewed and asymmetrical in the presence of publication bias and other biases Funnel plot asymmetry, measured by regression analysis, predicts discordance of results when meta-analyses are compared with single large trials Funnel plot asymmetry was found in 38% of meta-analyses published in leading general medicine journals and in 13% of reviews from the Cochrane Database of Systematic Reviews Critical examination of systematic reviews for publication and related biases should be considered a routine procedure

Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries.

Abstract: This article provides an update on the global cancer burden using the GLOBOCAN 2020 estimates of cancer incidence and mortality produced by the International Agency for Research on Cancer. Worldwide, an estimated 19.3 million new cancer cases (18.1 million excluding nonmelanoma skin cancer) and almost 10.0 million cancer deaths (9.9 million excluding nonmelanoma skin cancer) occurred in 2020. Female breast cancer has surpassed lung cancer as the most commonly diagnosed cancer, with an estimated 2.3 million new cases (11.7%), followed by lung (11.4%), colorectal (10.0 %), prostate (7.3%), and stomach (5.6%) cancers. Lung cancer remained the leading cause of cancer death, with an estimated 1.8 million deaths (18%), followed by colorectal (9.4%), liver (8.3%), stomach (7.7%), and female breast (6.9%) cancers. Overall incidence was from 2-fold to 3-fold higher in transitioned versus transitioning countries for both sexes, whereas mortality varied <2-fold for men and little for women. Death rates for female breast and cervical cancers, however, were considerably higher in transitioning versus transitioned countries (15.0 vs 12.8 per 100,000 and 12.4 vs 5.2 per 100,000, respectively). The global cancer burden is expected to be 28.4 million cases in 2040, a 47% rise from 2020, with a larger increase in transitioning (64% to 95%) versus transitioned (32% to 56%) countries due to demographic changes, although this may be further exacerbated by increasing risk factors associated with globalization and a growing economy. Efforts to build a sustainable infrastructure for the dissemination of cancer prevention measures and provision of cancer care in transitioning countries is critical for global cancer control.