Evidence into Practice: how to read a paper Rob Sneyd (with help from...Andrew F. Smith, Lancaster, UK)

Outline Evidence-based medicine Appraisal of published trials The anatomy of a journal

Four steps to evidence-based practice 1.Ask a clinical question 2.Search for evidence 3.Critically appraise the evidence 4.Integrate the evidence into practice

Levels of evidence ISystematic review of RCTs IISingle RCT III Cohort studies IVCase series VSingle case report

Appraisal of published studies

Is this paper any good? 1.Validity 2.Applicability 3.Logical flow

Validity: bias and distortion

Bias in clinical trials Recruitment Selection Allocation Performance Observer Inference Reviewer

Bias in clinical trials Recruitment Selection Allocation Randomisation PerformanceBlinding ObserverBlinding Inference Reviewer

Introduction

Method Introduction

Method Meaningful outcomes Inclusion and exclusion Detail - replicability Measurement tools Allocation concealment Blinding and control groups Follow-up and dropouts Power calculation and significance

Method Results Introduction

Method Discussion Results Introduction

Discussion Summary of main findings Comment on strengths and weaknesses Comparison with other studies – similarities and differences Mechanisms and implications Unanswered questions and future work

Method Conclusion Discussion Results Introduction

Method Conclusion Discussion Results Abstract Introduction

Anatomy of the anaesthesia journal

Editorials Rarely contain primary data Help interpret research and promote its use in practice Promote discussion Offer authoritative opinion

What are review articles for? Answering clinical questions Keeping up to date Starting-point for future research Assimilating primary research

Systematic review A review in which evidence on a topic has been systematically identified, appraised and summarised according to predetermined criteria

Systematic review 1.Decide scope and purpose 2.Exhaustive search for material 3.Inclusion on pre-defined criteria 4.Quality assessment of relevant studies 5.Data extraction 6.Synthesis and integration 7.Interpretation

Case reports Focus on individuals rather than populations Narrative power Archive of collective experience Sensitive to novelty: new benefits, complications, the unknown and unrecognised

Correspondence The proper dialogue of science Extend journals peer review by readers comments, corrections and interpretation Not usually peer reviewed Under-rated and poorly indexed

Conclusion Simple non-statistical principles can help make sense of research Evidence and opinion both have their place but should not be confused Bias is everywhere and must be taken into account Critical appraisal helps us identify good evidence