Evidence-based surgery : a gudie to understanding and interpreting the surgical literature

Preface
Contents
Contributors
1 History of Evidence-Based Surgery (EBS)
	References
2 The Steps of Practicing Evidence-Based Surgery (EBS)
	References
3 Developing a Surgical Clinical Research Question: To Find the Answer in Literature Search or in Pursuing Clinical Research
	The FINER Criteria
		Feasible
		Interesting
		Novel
		Ethical
		Relevant
	The PICOT Format
		Patient or Population
		Intervention
		Comparative Intervention or Control
		Outcome
		Time Horizon
	References
4 Finding the Evidence Through Searching the Literature
	Introduction
	Clinical Scenario
	Clinical Question
		Importance of the Question
	Developing a Search Strategy
		Identifying Concepts
		Identifying Search Terms
		Controlled Vocabulary
		Boolean Operators
	Creating a Search Strategy
		Simple Search Strategy (i.e., Basic)
		Complex Search Strategy (i.e., Advanced)
		Limits and Search Filters
	Choosing Appropriate Resources
		Pyramid of EBM Resources
		6S Pyramid
		Other Resources
	Keeping Current
	Resolution of the Clinical Scenario
	Conclusion
	References
5 Hierarchy of Evidence in Surgical Research
	Introduction
	Levels of Evidence for Therapeutic Research
		Clinical Example
	Levels of Evidence for Diagnostic Research
		Clinical Example
	Levels of Evidence for Prognostic Research
		Clinical Example
	Levels of Evidence for Economic Research
		Clinical Example
	Summary
	Concluding Remarks
	Appendix 1: Oxford Centre for Evidence-Based Medicine 2011 Levels of Evidence [3]
	References
6 Evaluating Surgical Interventions
	Clinical Scenario
	Search Strategy
	Appraisal of an Article: Are the Results Valid?
		Was Patient Assignment Randomized, and was the Randomization Process “Concealed”?
		Were Study Personnel “Blinded” to Treatment and Apart from the Experimental Intervention, Were the Groups Treated Equally?
		Were All Patients Who Entered the Trial Accounted for and Was Follow-up Adequate?
		Were Patients Analyzed According to the “Intention to Treat” Principle?
		Was the Study Large Enough to Detect a Difference?
	What Are the Results?
		What Outcomes Were Used and How Were They Measured?
			Binary Versus Continuous Outcomes
			Univariate Testing: Univariable and Multivariable Analyses
			Multivariable Regression Results: Odds Ratios (OR) and Risk Ratios (RR)
		How Large Was the Treatment Effect?
		How Precise was the Estimate of the Treatment Effect?
	Are the Results Applicable to My Patients?
		Were the Study Patients Similar to My Patients?
		Were the Measured Outcomes Clinically Relevant?
		Are My Surgical Skills Similar to Those of the Study Surgeons?
	Resolution of the Clinical Scenario
	References
7 A Primer on Outcome Measures for Surgical Interventions
	Clinical Scenario
	Information on Outcome Measures
	Choosing the Proper Outcome Measure
	How Can I Know if I Can Trust the Score?
	How Can I Interpret the Score in Clinical Practice?
	What Cautions Should I Exercise?
	Application of Above-Mentioned Concepts to Resolve the Clinical Scenario
	References
8 Patient-Important Outcome Measures in Surgical Care
	Scenario
	Searching the Literature
	Introduction
		What is a Patient-Reported Outcome?
		Other Important Concepts and Definitions
		How is a PROM Developed?
		How Do You Evaluate a PROM?
			Validity
		Reliability
		Classical Test Theory Versus Modern Psychometric Test Theory
		What Are the Different Types of PROMs?
	Applying the Literature to Patients
		How Do You Interpret Results?
		Resolution of the Scenario
	Appendix 1. Articles found in literature search
	References
9 Surrogate Endpoints
	Clinical Scenario
	Introduction
	Beware! Confounders
		Literature Search
		Are the Results Valid?
		What Are the Results?
	Are the Results Applicable to My Patients?
	Resolution of Clinical Scenario
	Conclusion
	References
10 How to Assess an Article that Deals with Health-Related Quality of Life
	Introduction
	Clinical Scenario
	Literature Search
	Primary Guides
		Have the Investigators Measured Aspects of Patients’ Lives that Patients Consider Important?
		Have Important Aspects of HRQL Been Omitted?
		Are the HRQL Instruments Chosen Valid, Reliable and Responsive?
	Secondary Guides
		Were HRQL Assessments Appropriately Timed to Evaluate the Effects of the Surgical Intervention?
		If There Were Trade-Offs Between Quantity and Quality of Life, Did the Investigators Perform a Economic Analysis?
	What Were the Results?
		What Was the Magnitude of the Effect on HRQL?
	Will the Results Help Me in Caring for My Patients?
		Will the Information from This Study Help Me Inform My Patients?
	Resolution of the Scenario
	References
11 Randomized Controlled Trial Comparing Surgical Interventions
	Introduction
	Scenario
	Literature Search
	Summary of the Appraised Article
	Evaluating a Randomized Controlled Trial
		Are the Results Valid?
			Learning Curve and Expertise-Based Randomized Controlled Trials
			Patient Randomization and Allocation Concealment
			Were Patients, Surgeons, and Researchers Aware of Group Assignment (Blinding)?
			Were the Patients in Each Group Similar?
			Intention-to-Treat Analysis
			Treatment Standardization
			Sample Size Calculation and Follow-Up
		What Are the Results?
			What Was the Impact from the Treatment?
			How Precise Were the Results?
		What Now?
			Generalizability
			Clinical Relevance
			What Does This Mean for Me as a Healthcare Provider?
	Resolving Our Clinical Scenario
	References
12 How to Assess a Pilot Trial in Surgery
	Clinical Scenario
	Definition of Pilot Trials
	Importance or Necessity of Conducting a Pilot Trial
	Current Practice in Pilot Trials in the Literature
	Key Considerations for Designing a Pilot Trial
	Study Rationale
	Objective(s) and Outcomes(s)
	Sample Size
	Methods of Analysis
	Criteria of Success
	Reporting of a Pilot Trial
	Key Resources for Further References
	Returning to the Scenario
	Concluding Remarks
	Appendix
	References
13 Non-inferiority Randomized Controlled Trials
	Clinical Scenario
	Literature Search
	Randomized Controlled Trials
	Non-inferiority RCT Design
	Conclusion
	Appendix
	References
14 Expertise-Based Randomized Controlled Trials
	Clinical Scenario
	Introduction
	Literature Search
	Are the Results Valid?
		Was the Learning Curve Taken Into Consideration?
		Were the Subjects Randomized?
		Was the Randomization Concealed?
		Were the Experimental and Control Groups Similar in Terms of Prognostic Factors?
		Were the Subjects Stratified?
		Were Subjects Analysed in the Group They Were Initially Randomized into at Enrolment?
		Was Follow-Up Complete?
	What are the Results of the Trial?
		How Were the Results of the Trial Being Measured?
		How Large Is the Treatment Effect ?
	Are the Results Applicable to Clinical Practice?
		Does the Study Represent My Patient Population?
		Does the Trial Consider All Relevant Patient-Important Outcomes?
		Do the Benefits of the Procedure Outweigh Any Potential Risks and Costs?
	Conclusion
	Resolution of Scenario
	References
15 The Surgeon’s Guide to Systematic Review and Meta-Analysis
	Introduction
	Clinical Scenario
	Finding the Evidence
		Are the Results Valid?
			Did the Review Address a Sensible Clinical Question?
			Was the Search for Relevant Studies Detailed and Exhaustive?
			Was Publication Bias Assessed?
			Were the Primary Studies of High Methodological Quality?
			Were Assessments of Studies Reproducible?
		What Are the Results?
			Were the Results Similar From Study To Study?
			What Are the Overall Results of the Review?
			How Precise Were the Results?
		Can I Apply the Results to My Patients?
			How Can I Best Interpret the Results and Apply Them to My Patients?
			Were All Patient-Important Outcomes Considered?
			Is the Benefit Worth the Potential Costs and Risks?
	Resolution of the Clinical Scenario
	Conclusion
	Appendix 1: Search Results
	Appendix 2: Prisma Flow Diagram [23, 38]
	References
16 Prospective and Retrospective Cohort Studies
	Introduction
	Clinical Scenario
	Literature Search
	Article Summary
		What are the Study’s Research Question and Clinical Relevance?
		Are the Results Valid?
			What is the Study Population?
			Are the Data Sources Reliable?
			Are the Data Collection Methods Sound?
			Do the Authors Provide Clear and Justifiable Definitions of the Primary and Secondary Outcomes?
			Have the Authors Accounted for Potential Sources of Bias?
			Is the Statistical Analysis (a) Valid and (b) Described Clearly?
		What Are the Results?
			Are Baseline Characteristics of the Exposure Groups Clearly Reported and Accounted For?
			Are the Results and Relevant Statistics Clearly Stated?
			How Precise Were Estimates of Effect Size?
			Are Results Robust to Planned Sensitivity Analyses?
			Were Subgroup Analyses Used? If So, Were these Specified a Priori and is the Issue of Multiple Testing Addressed?
		How Can I Interpret these Results in the Context of My Clinical Practice?
			Are the Results of the Study Placed in the Broader Context of the Clinical Question?
			Is There a Description of the Existing Literature?
			Were All Clinically Important Outcomes Considered?
			Are Limitations of the Study Clearly Described?
	Resolution of the Clinical Scenario
	Conclusion
	References
17 Case-Control Studies
	Introduction
	Clinical Scenario
	Literature Search
	Appraisal of the Selected Article
	Are the Results Valid?
	What Are the Results?
	How Can I Apply the Results to My Patients in a Clinical Practice?
	Resolution of the Scenario
	Additional Information for the Reader
	Appendix 1
	Appendix 2
	References
18 Evaluating Case Series in Surgery
	Introduction
	Clinical Scenario
	Literature Search
	Appraisal of a Surgical Case Series
	Resolution of Clinical Scenario
	Conclusion
	References
19 Quality Improvement and Patient Safety in Surgery
	Clinical Scenario
	Literature Search
	Introduction
	Background
	What is Quality Improvement?
	Is QI Research?
	Discussion
	Resolution of the Clinical Scenario
	Conclusion
	References
20 Diagnostic Studies in Surgery
	Introduction
		Clinical Scenario
		Literature Search
		Brief Study Summary
		Important Aspects of Diagnostic Studies
	Evaluating the Literature on a Diagnostic Test
	Appendix 1: Results of Cochrane Literature Review
	Appendix 2: Results from PubMed Literature Search
	References
21 How to Assess a Prognostic Study
	Clinical Scenario
	How and Why We Measure Prognosis?
	Study Designs for Prognostic Studies
	Literature Search
	Appraising the Surgical Literature on Prognosis
		Is the Sample Representative?
		Was Follow-up Sufficiently Long and Complete?
		Were Objective and Unbiased Outcome Criteria Used?
		How Likely are the Outcomes 	to Occur Over Time?
		How Precise are the Estimates of Likelihood?
		Can I Apply the Results to my Practice or Patient?
	Resolution of Clinical Scenario
	References
22 Decision Analysis and Surgery
	Clinical Scenario
	Literature Search
	Background on Decision Analysis in Surgery
	Components of Decision Analysis
		Decision Tree
		The Outcomes
		Clinical Application
	Users’ Guide: A Framework
	Are the Results Valid?
	What are the Results?
	Will the Results Help me in Caring for My Patient?
	Resolution of the Scenario
	Appendix 1. Articles Located During Literature Search
	References
23 Economic Evaluations in Surgery
	Explanation of the Types of Economic Evaluations and Terminology Used
	Formulas Used in Economic Evaluations that Inform Adoption of Novel Surgical Interventions
		For Cost Analysis
		For Cost-Effectiveness Analysis
		For Cost–Utility Analysis
		For Cost–Benefit Analysis
	Sensitivity Analysis
	Clinical Scenario
	Finding the Evidence
	Are the Results Valid?
		Did the Analysis Provide a Full Economic Comparison of Healthcare Strategies?
		Were Relevant Viewpoints Considered?
		Were All Relevant Clinical Strategies Compared?
	Were the Costs and Outcomes Properly Measured and Valued?
		Was Clinical Effectiveness Established?
		Were Costs Measured Accurately?
		Were Data on Costs and Outcomes Appropriately Integrated?
		Was Appropriate Allowance Made for Uncertainties in the Analysis?
		Are Estimates of Costs and Outcomes Related to the Baseline Risk in the Treatment Population?
	What Are the Results?
		What Were the Incremental Costs and Outcomes Between the Two Strategies?
		Do Incremental Costs and Outcomes Differ Among Subgroups?
		How Much Does Allowance for Uncertainty Change the Results?
	Will the Results Help Me in Caring for My Patients?
		Are the Treatment Benefits Worth the Harms and Costs?
		Could a Clinician’s Patients Expect Similar Health Outcomes?
		Can I Expect Similar Costs?
	Resolution of the Scenario
	Final Thoughts and the CHEERS Statement
	References
24 Studies Reporting Harm in Surgery
	Clinical Scenario
	Introduction
	Finding the Evidence
	Study Appraisal
	Conclusion
	Resolution of the Scenario
	Appendix 1
	References
25 Evaluating Surveys and Questionnaires in Surgical Research
	Introduction
	Clinical Scenario
	Literature Search
	Appraisal of a Surgical Survey
	Resolution of Clinical Scenario
	Conclusion
	References
26 Opinion Pieces in Surgery
	Clinical Scenario
	Literature Search
	Expert Opinion in the Context of Evidence-Based Medicine and Surgery
	What Is the Value of Expert Opinion?
	What Are the Limitations of Expert Opinion?
	Expert Opinion in the Context of the Surgical Literature
	Does Expert Opinion Apply to Me?
	Should I Trust an Expert Opinion
		Clinical Knowledge
		Technical Knowledge
		Perception as an Expert
		Conflict of Interest
	Resolution of Case
	Appendix 1: Articles Identified in Literature Search
	References
27 Simple Statistical Tests and P Values
	Clinical Scenario
	Literature Search
	Chapter Goal
	Critical Evaluation of the Paper for Reporting RCTs
	Statistical Tests and P Values
		Could All of This Be Due to the Play of Chance?
	Computing the Test Statistic
		What Does the Number Mean to a Reader?
		Where Do P Values Come from?
			Confidence Intervals
			Software
			Sensitivity Analysis
			Multiplicity
			Resolution of Clinical Scenario
	Reporting Statistical Findings in the Surgical Literature
	Appendix 1: Articles Identified in the Literature Search
	Appendix 2: Sensitivity Analysis for Table 27.3 Using Chi-Square Test and Minitab 18
	Appendix 3: Risk of Bias Scoring of the Barberan-Garcia et al. [1] Paper
	References
28 Confidence Intervals
	Clinical Scenario
	Understanding Confidence Intervals
	Why Are CI’s Different from p-Values?
	Getting to Estimation
	Hypothesis Testing
	How Do We Calculate Confidence Intervals?
	Why Use Confidence Intervals?
	Back to Our Scenario
	Appendix 1
	Appendix 2
	References
29 Power and Sample Size
	Clinical Scenario
	The Importance of Power and Sample Size
	Article Selection
	Summary of the Appraised Article by Oh et al. [21]
	Questions Used to Appraise
	Resolution of the Scenario
	Appendix 1
	Appendix 2: Using G*Power to Compute Power [30]
	Appendix 3
	Appendix 4
	References
30 Subgroup Analyses in Surgery
	Introduction
	Clinical Scenario
	Literature Search
		Summary of the Appraised Article
		Appraisal of the Selected Article
	Resolution of the Scenario
	Appendix 1
	References
31 Introduction to Clinical Practice Guidelines
	Introduction
	Clinical Scenario
	Literature Search
	Appraisal of Clinical Practice Guidelines: AGREE II and AGREE-REX Tools
	Are the Results Valid?
	What Are the Results?
	How Can I Apply the Results to Patient Care?
	Resolution of Clinical Scenario
	Conclusions
	References
Index