Evidence-Based Medicine Systematic Reviews & Meta-Analysis PDF

Evidence-Based Medicine Systematic Reviews & Meta-Analysis Sean T. Grambart DPM FACFAS Assistant Professor and Assistant Dean of Clinical Affairs College of Podiatric Medicine and Surgery Evidence-Based Medicine Clinical...

Evidence-Based Medicine Systematic Reviews & Meta-Analysis Sean T. Grambart DPM FACFAS Assistant Professor and Assistant Dean of Clinical Affairs College of Podiatric Medicine and Surgery Evidence-Based Medicine Clinical Expertise Patien t Care Patient Best Values Evidence 2  Systematic Reviews, Meta-Analysis, Evidence Guidelines Prospective Cohort Studies RCTs Hierarchy of Case Control EBM Retrospective Cohort Study Case Series Expert 3 Basis for Clinical Unit of Decision Marker Measuring Device Measurement Evidence Randomized Controlled Meta-Analysis Odds Ratio Study Eminence Radiance of White Hair Luminometer Optical Density Vehemence Level of Stridency Audiometer Decibels Eloquence Smoothness of Tongue Teflometer Adhesin Score Providence Level of Religious Fervour Angle of Genuflection Units of Piety Diffidence Level of Gloom Nihlometer Sighs Nervousness Litigation Phobia Level Every Conceivable Test Bank Balance Confidence Bravado Sweat Test No Sweat  Formulate Answerable Question Gather the Evidence Steps of EBM Appraise the Evidence Implement the Evidence Evaluate the Process 5 Systematic Review vs. Literature Review  The large amount of medical literature requires clinicians and researchers alike to What is the rely on systematic reviews in order to make an informed decision Significance of Systematic Reviews minimize bias Systematic More scientific method of summarizing Reviews? literature because specific protocols are used to determine which studies will be included in the review 7  The volume of published material makes it impractical for an individual Why are clinician to remain up to date on a variety of common conditions Systematic Reviews Further complicated when individual studies report conflicting conclusions, Necessary? a problem that is prevalent when small patient samples and retrospective designs are used 8  Clearly stated title and objectives Key Comprehensive strategy to search for relevant studies (unpublished and published) Characteristics Explicit and justified criteria for the inclusion or of Systematic exclusion of any study Reviews Clear presentation of characteristics of each study included and an analysis of methodological quality Comprehensive list of all studies excluded and justification for exclusion 9  Clear analysis of the results of the eligible studies Characteristics Statistical synthesis of data (meta-analysis) if appropriate and possible of Systematic Qualitative synthesis Reviews Structured report of the review clearly stating the aims, describing the methods and materials and reporting the results 10 Systematic Review Comprehensive high-level summary of primary research on a specific research question Attempts to identify, select, synthesize, and appraise all high- quality evidence relevant to that question to answer it Collate all evidence pertinent to a selected criteria for eligibility to address the specific research question Identify and minimize bias via transparent, explicit, and systematic methodology 11 PRISMA PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines The 27-item checklist was intended to improve review quality, not generate a review quality score 13 15 Hypothesis A systematic review should be based on principles of Knowledge that is acquired hypothesis testing, and the independently of any hypotheses must be experience conceived a priori 16 PURPOSE OF THE REVIEW: IDENTIFYING AN ANSWERABLE QUESTION(S) Answer an important answerable clinical question or identify areas of high clinical importance that are underreported in the medical literature The question must be specific; however, it must not be too specific An appropriate question should be original and focused on the precise identification of the participant(s), intervention(s), comparison(s), outcome(s), and study design (PICOS criteria) 17  Inclusion/Exclusion Criteria Once the study question is To avoid selection bias, formalized, the authors must inclusion and exclusion criteria compose a comprehensive list should be agreed upon and of inclusion and exclusion formalized before data criteria extraction and analysis 18 ELIGIBLE STUDIES: INCLUSION AND EXCLUSION CRITERIA Demonstrates the identification and screening of potentially eligible studies determines the final number of studies included for analysis It is not uncommon to need to alter criteria as the study search strategy ensues 19 ELIGIBLE A minimum STUDIES: Critical evaluation of eligible studies level of evidence may be an inclusion INCLUSION criterion AND The highest level of EXCLUSION evidence should always be sought but not ‘‘best available evidence’’ CRITERIA an absolute 20 PRIMARY AND EXPLORATORY OUTCOMES The primary study outcomes should be ascertained before the studies are selected and analyzed It is the measure upon which success or failure of an intervention is based 21 Literature Search Challenges Database Bias - No single database is likely to contain all published studies on a given subject Publication Bias - selective publication of articles that show positive treatment of effects and statistical significance It is important to search for unpublished studies through a manual search of conference proceedings, correspondence with experts, and a search of clinical trials registries 22  English-language bias - occurs when Literature reviewers exclude papers published in languages other than English Review Challenges Citation bias - occurs when studies with significant or positive results are (cont.) referenced in other publications, compared with studies with inconclusive or negative findings 23  The search strategy should be strictly focused on the PICOS criteria PRISMA flowchart should be created to illustrate study identification, screening, eligibility, SEARCH inclusion, and analysis METHODOLOGY PubMed, Cochrane Library, CINAHL, Scopus, Embase The initial search’s specificity must not compromise the sensitivity 24 EXTRACTION AND ANALYSIS OF STUDY DATA: REPORTING THE RESULTS 25  EVALUATION OF STUDY METHODOLOGICAL QUALITY The quality of a systematic review is only as good as the studies that it analyzes 26  Utilizes statistical methods (as differentiated from systematic reviews) to quantitatively evaluate pooled data from single studies Meta- Individual studies are assigned a weight-based on the sample size Analysis Conclusions are reported based on the accuracy and precision (mean and confidence interval [CI] relative to a ‘‘zero effect’’ line on a forest plot) of individual studies’ results Statistical technique for combining the results of independent, but similar, studies to obtain an overall estimate of treatment effect 27 Meta-Analysis While all meta-analyses are based on systematic review of literature, not all systematic reviews necessarily include meta-analysis If a meta-analysis is to be included in a systematic review, an experienced statistician or an epidemiologist should be consulted during all phases of the study 28  The final, and most important, step in the systematic review is the reporting of the ‘‘take-home points’’ SUMMARIZE This limited amount of text is the authors’ single opportunity to convey the key findings of the review THE Authors must address their answerable question(s) and whether their hypothesis or hypotheses were confirmed FINDINGS Authors must also acknowledge the limitations identified in the analyzed studies There is no room for speculation or discussion in this section, only the facts 29 A meta-analysis does not necessarily mandate comprehensive inclusion of all studies relevant to a specific topic as in a systematic review Not all meta-analyses are systematic reviews Not all systematic reviews are meta-analyses unless all studies are identified, included, and analyzed (systematic review) quantitatively (meta-analysis) 30 Meta- analysis: The Common questions addressed in meta- analysis are whether one treatment is more Research effective than another or if exposure to a certain agent will result in disease Question 31 Steps of Meta-analysis 1 2 3 4 5 6 Define the Perform the Select the Extract the data Analyze the Report the Research literature studies data results Question search 32 Questions?