How to interpret a meta-analysis and judge its value as a guide for clinical practice

Zlowodzki, Michael; Poolman, Rudolf W.; Kerkhoffs, Gino M. M. J.; Tornetta, Paul; Bhandari, Mohit

doi:10.1080/17453670710014284

Cited by 94 publications

(72 citation statements)

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“…24 The I 2 test was used to quantify statistical heterogeneity of the studies. 25 A value of 25% reflects low heterogeneity, 50% is moderate and 75% represents high heterogeneity. A p value of <0.1 was used to indicate that the heterogeneity was not due to chance alone, and it would be inappropriate to combine the results in a summary.…”

Section: Data Extraction and Analysismentioning

confidence: 99%

Does exercise training change physical activity in people with COPD? A systematic review and meta-analysis

et al. 2011

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A systematic review and meta-analysis was conducted to examine the effect of exercise training on daily physical activity (PA) in people with chronic obstructive pulmonary disease (COPD). MEDLINE, PubMed, EMBASE, CINAHL, Physiotherapy Evidence Database (PEDro) and Cochrane Central Register of Controlled Trials were searched from their inception to week 27 of 2010, using the keywords 'COPD,' 'exercise,' 'therapy' and 'physical activity.' All studies except case reports were eligible for inclusion provided they investigated the effects of !4 weeks of supervised exercise training on PA in patients with COPD. Study quality for the randomised trials (RTs) and single-group interventional studies was rated using the PEDro scale and Downs and Black Tool, respectively. No randomised controlled trials met our study criteria. The two RTs had a mean PEDro score of 5. The 5 single-group studies had a mean Downs and Black score of 19 + 3. When combined, a small effect on PA outcomes was demonstrated (overall mean effect ¼ 0.12; p ¼ 0.01). Taken together, the RTs and single-group studies demonstrate that exercise training may confer a significant but small increase in PA.

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Section: Data Extraction and Analysismentioning

confidence: 99%

Does exercise training change physical activity in people with COPD? A systematic review and meta-analysis

et al. 2011

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“…Redundant publications alter the assessment of treatment effects in meta-analysis. The transition toward evidence-based orthopaedics research has led to an explosive increase in the number of meta-analyses over the last decade, which is cause for increasing concern [39]. The publication of redundant data is not only unethical but also has a confounding effect on meta-analysis; furthermore, the practice also increases the costs of peer review.…”

Section: Prevention Of the Recycling Culture Of Research Performancementioning

confidence: 99%

Improvement of research quality in the fields of orthopaedics and trauma—a global perspective

Fayaz

Haas

Kellam

et al. 2013

International Orthopaedics (SICOT)

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The international orthopaedic community aims to achieve the best possible outcome for patient care by constantly modifying surgical techniques and expanding the surgeon's knowledge. These efforts require proper reflection within a setting that necessitates a higher quality standard for global orthopaedic publication. Furthermore, these techniques demand that surgeons acquire information at a rapid rate while enforcing higher standards in research performance. An international consensus exists on how to perform research and what rules should be considered when publishing a scientific paper. Despite this global agreement, in today's "Cross Check Era", too many authors do not give attention to the current (2013( ) 37:1205( -1212( DOI 10.1007( /s00264-013-1897 standards of systematic research. Thus, the purpose of this paper is to describe these performance standards, the available choices for orthopaedic surgeons and the current learning curve for seasoned teams of researchers and orthopaedic surgeons with more than three decades of experience. These lead to provide an accessible overview of all important aspects of the topics that will significantly influence the research development as we arrive at an important globalisation era in orthopaedics and trauma-related research.

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“…The outcome in meta-analysis, the effect size, is often reported as weighted mean difference or standard mean difference (Zlowodzki et al, 2007). Zlowodzki et al (2007) summarized that effect sizes are defined, according to Cohen (1988), as a large effect size equal to or greater than 0.8, a medium size is equal to 0.5, and 0.2 is a small effect size. In meta-analysis, a test for homogeneity can be conducted to examine variation among the studies.…”

Section: Introduction Of Meta-analysismentioning

confidence: 99%

“…Meta-analysis is classified as a type of systematic review (Zlowodzki, Poolman, Kerkhoffs, Tornetta III, & Bhandari, 2007), and is defined as a "statistical analysis of a collection of analytic results for the purpose of integrating the findings," and combining findings from a collection of studies "represents an attractive alternative to strengthen the evidence about the treatment efficacy" (DerSimonian & Laird, 1986, p. 177). Borestein et al (2009) stated that in meta-analysis, individual effect size for each study and summary effect are computed to evaluate the level of effectiveness of the treatment and the relationship between two variables.…”

Section: Introduction Of Meta-analysismentioning

confidence: 99%

A Meta-Analysis of School-Based Childhood Obesity Prevention Programs

Hung

Tidwell

Hall

et al. 2011

Journal of the American Dietetic Association

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The prevalence rate of childhood obesity has increased rapidly worldwide. The childhood obesity epidemic is associated with many adverse health consequences in children as well as a financial burden for a nation's economy. A meta-analysis was conducted to investigate the effectiveness of school-based childhood obesity prevention programs in preventing childhood obesity. The objectives of this study were to 1) identify the most effective childhood obesity prevention programs through effect size comparison, and 2) identify important program components that affect the effectiveness of the intervention through subgroup analysis. The Comprehensive Meta-Analysis (CMA)program was used for all statistical analyses. Results of the meta-analysis demonstrated that the summary effect size was small (d = 0.039, 95% confidence interval). The schoolbased program identified in the meta-analysis as the most effective had a d value of 0.368. Subgroup analyses were performed because this meta-analysis study was heterogeneous (Q = 167.774, p = 0.001) with an I 2 value of 68.410%. The subgroup moderators were length of program duration, age of participants, nutrition, physical activity, parental involvement, specialist involvement, and theory based versus nontheory based intervention programs. Subgroup analyses demonstrated that significant differences (p < 0.05) occurred among the moderator components. Programs that targeted younger children less than ten years old and programs that were theory based were more effective. The meta-analysis study contained publication bias because the funnel plot was skewed and smaller studies were missing. To further explore the publication bias problem, Classic fail-safe N and Duval and Tweedie's trim and fill analyses were performed. Classic fail-safe N indicated that two programs were missing from the present study to achieve a non-biased result. The Duval and Tweedie's trim and fill analysis demonstrated that a small mean effect size difference was detected between the present observed studies and the unbiased effect size. The small mean effect size difference indicated that the results and the reported effect sizes in this meta-analysis study were valid.Key words: meta-analysis, school-based childhood obesity prevention, subgroup analysis ii ACKNOWLEDGEMENTS I want to take this opportunity to express my special thanks to Dr. Diane Tidwell, my major professor, who has guided me through this long dissertation writing process.She has been so patient and supportive to help me with the statistical questions regarding meta-analysis study. I want to thank her for editing not only my dissertation but also my papers. I have asked for her help numerous times, and she has never said no to me.

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How to interpret a meta-analysis and judge its value as a guide for clinical practice

Abstract: On behalf of the International Evidence-Based Orthopedic Surgery Working Group (2007) How to interpret a meta-analysis and judge its value as a guide for clinical practice,

Cited by 94 publications

References 50 publications

Does exercise training change physical activity in people with COPD? A systematic review and meta-analysis

Does exercise training change physical activity in people with COPD? A systematic review and meta-analysis

Improvement of research quality in the fields of orthopaedics and trauma—a global perspective

A Meta-Analysis of School-Based Childhood Obesity Prevention Programs

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