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- Herausgeber: John Wiley & Sons
- Kategorie: Fachliteratur
- Serie: ABC Series
- Sprache: Englisch
ABC of
Evidence - Based Healthcare
A practitioner guide summarizing the aims and achievements of evidence-based healthcare and why it is crucial to modern clinical practice
ABC of Evidence-Based Healthcare explains how evidence is developed and formulated into guidance for clinicians. It details how to interpret and apply this evidence to one’s own practice and patients, covering areas such as diagnosis and screening, therapy, harm, and prognosis. Some of the key aspects discussed in this book include understanding choice of study design, the roles of quantitative and qualitative research, selecting and using appraisal tools and key statistical concepts. Additionally, the book also covers how to interpret the results of research studies, apply results to the needs of patients, communicate results to colleagues and incorporate them into student training, as well as discussing treatment options, risks, and benefits with patients.
As in all ABC books, the text is complemented with practical examples of evidence in practice to facilitate understanding. Although a standalone resource in itself, the book signposts readers to useful and comprehensive resources, including web-based calculators and tools for each main theme of the book.
In ABC of Evidence-Based Healthcare, readers will find information on:
- The ethical dimension, philosophy, scope, achievements, and usefulness of evidence-based healthcare
- Pre-appraised versus primary studies, healthcare databases, and search strategies including the use of keywords, wildcards, and filters
- Statistical concepts including probability and confidence intervals, and cohort, diagnostic accuracy, and case control studies
- Bias in research, the impact of under-research, conflicts of interest, and misleading or weak evidence
- Curriculum development, covering objectives and outcomes, curriculum integration, and student assessments
ABC of Evidence-Based Healthcare delivers a practical, accessible, and highly useful introduction to concepts of evidence-based healthcare for students and new practitioners.
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Veröffentlichungsjahr: 2025
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Table of Contents
Cover
Table of Contents
Title Page
Copyright Page
List of Contributors
Preface
Chapter 1: What Is Evidence‐Based Healthcare?
Introduction
Healthcare before evidence‐based healthcare
The philosophy of evidence‐based healthcare (4)
The origins of the evidence‐based healthcare movement
Using evidence at the bedside
The achievements of evidence‐based healthcare
The key steps of evidence‐based healthcare
So what is evidence‐based healthcare?
The ethical dimension
References
Chapter 2: Identifying Clinical Questions
Introduction
Clinical background questions versus foreground questions
Where do clinical questions come from?
Patient engagement
Types of clinical questions (6, 7)
Using the PICO framework (2, 8)
Finding evidence
Examples of differing types of clinical questions using the aforementioned structured approach
Health economics in clinical questions
The impact of answering clinical questions
Summary
References
Chapter 3: Finding the Evidence
Where is the evidence?
What is a database?
Medical summaries and databases
What is peer review?
Can’t I just use Google it?
Hierarchies of evidence – the evidence pyramids
Search strategies
Getting started
Deriving search terms
Exploding your search
Limiting a search to titles only
Using Boolean operators
Thesaurus
Comprehensive search strategies
Primary research papers
Internet searches
Grey literature
Selecting studies
Tips on abstract screening
Reporting a search
References
Chapter 4: Principles of Study Design
Introduction
Research study design
What type of study am I reading?
Accounting for bias in study design
Advantages and disadvantages of the designs
Cohort study
Case‐control studies
Cross‐sectional survey
Designing and planning a study
What is a clinical trial?
Evidence synthesis
Systematic reviews
Registration and reporting of results
References
Further reading
Chapter 5: Qualitative Research
Introduction
The qualitative research question
Qualitative study designs
Conducting a qualitative research study
Sampling (8)
Determining the sample size
Data collection
Interview topic guide
Principles of data analysis
Bias in qualitative research
Reporting qualitative research studies
Critical appraisal of qualitative research
Mixed methods
Generalisability of qualitative research
References
Chapter 6: Statistical Concepts
Introduction
Oh no, not statistics!
What are statistics for?
Types of data
Identifying data types
Descriptive and inferential statistics
Reporting central tendency
Visualising data
Transforming data
Sample point estimate (2)
Data accuracy and quality
Confidence intervals
Confidence intervals of a mean
Hypothesis testing
What is a P value?
Choosing statistical tests
Correlation and regression
Population and sampling
Diagnostic tests
Receiving operating characteristic (ROC) curves
References
Further reading
Chapter 7: Critical Appraisal
What is critical appraisal?
Validity
Initial points
The journal of publication
The title
Authorship
Initial questions (9)
The abstract
Introduction or background
Aims and objectives
Method
Results
Discussion/conclusions
Declarations
Assessing bias in studies
Inclusion in subgroup analysis
Reporting standards
Appraisal tools
Systematic reviews and meta‐analyses
Acknowledgements
References
Further reading
Chapter 8: Evidence into Practice
Introduction
Patient and public involvement
Knowledge‐to‐action cycle
Guidelines
Clinical reasoning, evidence, communication and shared decision‐making
Communicating risk to patients
References
Further reading
Chapter 9: Challenges in Evidence‐Based Healthcare
Inclusion in research
Artificial intelligence
‘Listen to the patient and their data; they are telling you the diagnosis’
Are there limitations to evidence‐based healthcare?
References
Chapter 10: Teaching and Learning Evidence‐Based Healthcare
The learner’s experience
Evidence is everywhere
Tips for evidence‐based bedside teaching
Practising the five steps of evidence‐based healthcare
The evidence‐based healthcare curriculum
Teaching strategies for evidence‐based healthcare
Journal clubs
Learner attitudes
Summary
References
Glossary
Bibliography
Useful Tools and Websites
Index
End User License Agreement
List of Tables
Chapter 1
Table 1.1 A light‐hearted perspective on alternatives to evidence‐based med...
Table 1.2 Impact of the evidence cart.
Table 1.3 Types of review published by the Cochrane Library.
Table 1.4 Themes and examples of Cochrane library systematic reviews.
Table 1.5 Use of ‘evidence‐based’ terms in the titles of articles published...
Table 1.6 Thirteen principles of the good clinical practice ethical, scient...
Chapter 3
Table 3.1 Commonly used bibliographic databases.
Table 3.2 Resources for evidence‐based practice.
Table 3.3 Examples of search results using Boolean operators.
Table 3.4 Tools for focusing literature searches.
Chapter 4
Table 4.1 Suitable study designs for clinical questions.
Table 4.2 Advantages and disadvantages of different study design.
Table 4.3 What type of systematic review should I conduct?
Table 4.4 Summary of reporting guidelines for each main study design.
Chapter 5
Table 5.1 Differences between quantitative and qualitative research.
Table 5.2 Advantages and disadvantages of methods of data collection in qua...
Table 5.3 Qualitative themes and subcategories from the non‐communicable di...
Table 5.4 Sources of bias in qualitative research.
Chapter 6
Table 6.1 Examples of studies of correlation and regression (5–8).
Table 6.2 Calculation of sensitivity and specificity using a 2 × 2 table.
Chapter 7
Table 7.1 Initial appraisal of different study designs.
Table 7.2 Differences between efficacy and effectiveness studies.
Table 7.3 Overview of journal impact factor.
Table 7.4 Types of bias in quantitative research.
Table 7.5 Tips to avoid different types of bias during a trial.
Table 7.6 Examples of widely used research reporting guidelines.
Table 7.7 Examples of commonly used appraisal tools.
Chapter 8
Table 8.1 Measures of magnitude or effect size encountered in preventive sc...
Chapter 9
Table 9.1 Achievements and limitations of EBM.
Chapter 10
Table 10.1 Kappa values for the respiratory examination.
Table 10.2 Comparison of the Centor criteria and FeverPAIN clinical predict...
Table 10.3 Course assignment and practice in the five steps of evidence‐bas...
Table 10.4 Checklists for clinical communication and risk communication ski...
List of Illustrations
Chapter 1
Figure 1.1 Simplified hierarchy of evidence (systematic review of all study ...
Figure 1.2 David Sacket demonstrating the evidence cart.
Figure 1.3 The five key steps of evidence‐based healthcare.
Chapter 2
Figure 2.1 The five‐step guide to practise evidence‐based medicine.
Figure 2.2 PUNs and DENs.
Chapter 3
Figure 3.1 Hierarchy of evidence for scientific research.
Figure 3.2 The 6‐S pyramid of research evidence.
Figure 3.3 Process of broad‐narrow search terms/articles identified. By ‘exp...
Figure 3.4 Building a search with Boolean operators.
Figure 3.5 PRISMA 2020 flow diagram for new systematic reviews which include...
Figure 3.6 PRISMA flowchart for a scoping review on clinical reasoning educa...
Chapter 4
Figure 4.1 Flow chart to assess the study design which has been used.
Figure 4.2 Flow chart for the structure of a randomised controlled trial.
Figure 4.3 Flow chart for design and analysis of a crossover trial.This ...
Figure 4.4 Design of a prospective cohort study.
Figure 4.5 Case‐control study design.
Figure 4.6 Cross‐sectional study design.
Figure 4.7 Principles for conceptual planning and implementation stages of c...
Figure 4.8 Steps in conducting a systematic review.
Chapter 5
Figure 5.1 Qualitative study flow diagram illustrating the study processes....
Figure 5.2 Conceptual framework of factors affecting non‐communicable diseas...
Chapter 6
Figure 6.1 The normal distribution showing symmetrical data dispersion (spre...
Figure 6.2 Non‐normal data distribution.
Figure 6.3 Examples of charts used to visualise data. These charts all conta...
Figure 6.4 Choice of test for comparing the means of two groups.
Figure 6.5 Choice of test for comparison of proportions or percentages betwe...
Figure 6.6 Likelihood ratios: diagnostic weights. Clinicians should classify...
Figure 6.7 Likelihood ratios: examples. From McGee, S. Likelihood ratios, de...
Figure 6.8 ROC demonstrating diagnostic accuracy of Well score in the diagno...
Chapter 7
Figure 7.1 Major sources of bias in clinical research.
Figure 7.2 Explanation of a funnel plot. The outer dashed lines indicate the...
Figure 7.3 Example of a forest plot from a meta‐analysis. Proportion of pati...
Chapter 8
Figure 8.1 Knowledge‐to‐action cycle.
Figure 8.2 Use of the active implementation framework for a community‐based ...
Figure 8.3 Five broad areas of clinical reasoning education.Clinical rea...
Figure 8.4 The Calgary Cambridge Guide – the expanded framework.
Figure 8.5 Evidence‐based healthcare and shared decision‐making.
Figure 8.6 Three‐talk model of shared decision‐making.
Figure 8.7 Overview of risk communication strategies.
Figure 8.8 Patient decision aid (PDA) for use of anticoagulation in the prev...
Figure 8.9 PDA visualising the risks of breast cancer.
Chapter 9
Figure 9.1 Tool for diversity, equity and inclusion within the clinical tria...
Figure 9.2 Health research inclusivity model.
Figure 9.3 Number of articles on the use of AI for automating or semi‐automa...
Figure 9.4 Steps in US Food and Drug Administration drug approval for clinic...
Figure 9.5 Use of AI in clinical trials.
Figure 9.6 Evidence‐based deep medicine iceberg.
Figure 9.7 From randomised controlled trials to personalised medicine.
Chapter 10
Figure 10.1 Flow chart outlining the structure of a diagnostic accuracy test...
Figure 10.2 Diagnosis of lobar pneumonia. Textbooks present 15 traditional, ...
Figure 10.3 Flow chart for evaluation of the effectiveness of a journal club...
Guide
Cover Page
Table of Contents
Title Page
Copyright Page
List of Contributors
Preface
Begin Reading
Glossary
Bibliography
Useful Tools and Websites
Index
WILEY END USER LICENSE AGREEMENT
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ABC ofEvidence‐Based Healthcare
Edited by
John Frain
Division of Medical Sciences and Graduate Entry MedicineUniversity of NottinghamNottingham, UK
This edition first published 2025© 2025 John Frain
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List of Contributors
John FrainDivision of Medical Sciences and Graduate Entry MedicineUniversity of Nottingham, Nottingham, UK
Alistair HewinsFinal Year Graduate Entry Medical Student, University of NottinghamNottingham, UK
Raj Himatshih BablaDivision of Medical Sciences and Graduate Entry MedicineUniversity of Nottingham, Nottingham, UKClinical Implementation Lead, Stoneygate Centre for Empathic HealthcareUniversity of Leicester, Leicester, UK
Preface
I am writing this book not as a researcher but as an end user of evidence‐based healthcare. What does this mean? It means I am a frontline clinician, in primary care, working to provide patients with care and management according to the best available evidence, helping them to interpret what they have seen, most commonly now, online but also in newspapers, on TV or simply by word of mouth from family and friends. I need to know how to retrieve and interpret evidence quickly and accurately. I need evidence to collaborate with my patients and to share decision‐making with them in line with their own preferences and values. Practising in primary care is often about the management of uncertainty – not only the patient’s but also mine and my team’s. The prospect of making our work more evidence‐based to assist our clinical judgement is certainly an attractive one. Healthcare is a team‐based activity, and the well‐being of patients is dependent on the well‐being of the staff. During the recent Covid‐19 pandemic, my practice continued to see our patients face‐to‐face whenever necessary. In a previously unknown and rapidly evolving situation, the availability of high‐quality evidence was essential in keeping our patients and staff safe.
The full implementation of evidence in healthcare is not a fixed endpoint nor even a destination to which we are yet close. Humankind has always sought to interpret the causes of disease and the benefits of available treatments. Though the quality of evidence for healthcare has improved immeasurably over the past 30 years, there remain challenges. These involve greater implementation of evidence into healthcare policy, everyday practice and the lives of patients, staff and healthcare providers. Amazingly, the ‘evidence cart’ can now be held in the hand and stored in the pocket. The technological revolution of the information age enables rapid retrieval of evidence to aid bedside decision‐making with just a few clicks. Yet not all available evidence is published, not every trial is well conducted and not every healthcare professional and policymaker is skilled in the appraisal of evidence. Still too often, historically underserved and marginalised individuals and communities remain outside the remit of mainstream research, reinforcing their often‐poorer health outcomes. This must change, and we have the tools to do this.
As an educator, I am aware of the great volume of knowledge and assessment with which healthcare students must contend. Evidence‐based healthcare can seem abstract and lacking relevance if it is only placed alongside other learning themes rather than embedded across the whole curriculum, informing the choice of what is to be taught to future healthcare professionals. Students need to become familiar with the skills and the benefits of evidence‐based healthcare right from the beginning of their training rather than seeing it as an ‘add‐on’ for a later date.
It is not within the scope of this book to cover everything in evidence‐based healthcare. I have tried to address the important domains across the skill set as well as to provoke thought for the reader of implementation and future challenges. Underpinning this, I have added details of suitable further resources readers may also wish to review.
Finally, I would like to thank everyone who has contributed to this book and to Wiley who have supported it from concept to publication. I hope it is useful and helps to provide the reader with an overview of this important topic in healthcare and provides direction to other resources and further study.
John Frain
August 2024
Chapter 1What Is Evidence‐Based Healthcare?
John Frain
Division of Medical Sciences and Graduate Entry Medicine, University of Nottingham, Nottingham, UK
OVERVIEW
Evidence is the available information or facts which indicate whether a belief or proposition is true.
Evidence in healthcare is linked to quality, patient safety and improved clinical outcomes.
The concept of justifying practice through the use of evidence can be found from the earliest times.
Modern evidence‐based practice has its roots in the development of critical appraisal and modern research methods.
The ethical dimension is essential in determining the quality and application of evidence.
Introduction
On explaining to a fellow new student on another university course that I was studying evidence‐based healthcare and how to bring evidence into our clinical practice, the alarmed response I received was, ‘You mean healthcare isn’t already evidence‐based?’ It seems obvious that something as important as healthcare should proceed only on the basis of the evidence, given the possible consequences of poor practice. The answer to my colleague’s concern is, of course, both ‘Yes, it is’ and ‘No, it isn’t or rather ‘There is evidence, but it could be better, both in terms of the knowledge and how the knowledge is applied to patient care’. It is always this tension between where practice is now and where it could be in the future, which should motivate both scientists and clinicians to always develop the scope of evidence further in our practice.
Evidence is not only static but also dynamic in the sense our depth of understanding should always be evolving. An example is finger clubbing, first described by Hippocrates in a patient with empyema in the sixth century BCE. Our understanding of clubbing is different from 2500 years ago (Box 1.1).
Therefore, observation is crucial in healthcare because it raises curiosity about the origin of the data, and in this case a physical sign clinicians see in their patients. Hippocrates’ initial observation of a patient’s fingers and his curiosity about a relationship (coincidence, association or causation?) with their empyema has evolved into an evidence‐based physical sign which remains important in physical diagnosis. These clinical questions are vital in clinical reasoning and decision‐making about a patient’s management. They divide into questions about general knowledge of a condition, disease or process (background questions) and specific questions to facilitate clinical decision about the patient in front of us (foreground questions) (Chapter 2) (Box 1.2).
The volume of medical knowledge and belief has evolved immensely. Currently, Medline is adding over a million new records to its database every year. Hippocrates alone wrote around 60 treatises (the Hippocratic Corpus) describing theories of disease, ethical dimensions and approaches to observation and physical examination. Now every busy clinician appreciates the need to access high‐quality information quickly and efficiently for the immediate benefit of patients. The need to summarise evidence and manage changing medical knowledge has been recognised since the seventeenth century with the publication of an abstracting journal in 1682 and the first medical journal in England, Medicina Curiosa, in 1684 (1). The development of indexing, databases and computerisation in the twentieth century has provided the automated databases and evidence retrieval we enjoy now, particularly in the last 30 years. These have facilitated an explosion in the opportunities for a more systematic and rigorous consideration of scientific evidence, which informs clinical practice today (Chapter 3). Many of us will remember the previous challenges of retrieving references for our student essays from the hefty volumes of the Index Medicus, followed by a search of the dusty shelves of a medical library stack room.
Comparing similar groups whose baseline characteristics are similar is particularly important in evaluating a new intervention and is the basis of the randomised controlled trial (RCT). Again, the concept has a long history, with the poet Francisco Petrarch proposing in the fourteenth century that the effects of then‐current treatments for conditions in one group be compared with a similar group of patients in which the natural history of the condition was allowed to proceed unchecked. A famous example is James Lind’s intervention in sailors with scurvy in 1747 (Box 1.3). The first recognised RCT is of the use of streptomycin in the treatment of pulmonary tuberculosis (2). Given the inherent variability of biological systems both individually and in populations, the precise comparison of groups required in accurately evaluating the effectiveness of interventions has led to the development of medical statistics to describe these effects accurately (Chapter 6).
Box 1.1 Understanding the clinical significance of finger clubbing ‘Hippocratic fingers’
Clubbing is characterised by a bulbous swelling of the terminal phalanges of the fingers. It was described first by Hippocrates, who observed it in a patient with empyema. Later it was found to be associated with many conditions, including bronchiectasis, lung cancer, liver cirrhosis, cyanotic congenital heart disease and infective endocarditis. In 1976, South African cardiologist Leo Shamroth observed in his own clubbed fingers an obliteration of the diamond‐shaped spaced normally seen when the dorsal surface of the nails are brought into contact with one another (Shamroth’s sign). A study in JAMA in 2010 found inter‐examiner agreement using Shamroth’s sign on the presence of clubbing to give kappa values of 0.3–0.9 and concluded its use reasonable in the identification of clubbing. Clubbing is present in 1% of patients admitted acutely to acute medical wards and is associated with serious disease in 40% of these patients.
Source: Pallarés‐Sanmartín et al. (20), Vandemergel and Renneboog (21).
Box 1.2 Examples of background and foreground questions
Background questions identify knowledge and understanding of disease processes or clinical conditions. They are often broad in scope and may be answerable from textbooks, general online sources and review articles. They may help information decision‐making about a foreground question and a particular patient but are not the answers in themselves about what is appropriate for a particular patient.
Example – What is the pathophysiology and prognosis of acute otitis media in children under two years?
Foreground questions require knowledge to assist decision‐making. They may involve a comparison of treatment options, including intervention. Answers to foreground questions require synthesis of primary studies and a comprehensive literature search. These may be used to produce an evidence summary or systematic review.
Example – Will prescribing oral antibiotics to my 18‐month‐old patient with acute otitis media improve or have any effect on their long‐term prognosis?
Healthcare before evidence‐based healthcare
Evidence existed before the 1990s, and anyone practising in that era knows clinicians both aspired to and did practise scientifically for the benefit of patients. What happened in 1992 and afterwards happened because of what came before, as well as the development of innovative technology and the inspirational leadership of individuals and academic departments in articulating a new vision for the evaluation and application of evidence in healthcare. First is the improvement in the evaluation of interventions and treatments. This has been achieved through better study design, including registration of trials, protocols and promotion of reporting standards (Chapter 4). In addition, the promotion of critical appraisal skills, including in healthcare training programmes, has enabled practitioners to exercise greater reflection and discernment in how to apply evidence to their own patients (Chapters 7 and 8). Even though light‐hearted in tone and certainly not advocated as viable alternatives, Isaacs and Fitzgerald’s perspectives on evidence‐based healthcare were written as a necessary counterpoint to the evidence‐based approach and the issues raised by it. It is worth reflecting on Isaacs and Fitzgerald’s thoughts on alternative methods of clinical decision‐making (Table 1.1). In all things, there should always be a healthy scepticism, if only to encourage necessary questioning and debate to flourish.
Box 1.3 James Lind and comparison of similar groups in the treatment of scurvy
Scurvy results from a lack of vitamin D. It was particularly prevalent in the Royal Navy in the eighteenth century. Provision of citrus fruits to Dutch sailors suggested a reduction in the disease. In 1747, James Lind, a Royal Navy surgeon, selected 12 sailors with scurvy ‘as similar as I could have them’. All sailors received the same diet. The sailors were divided into groups of two. Two were given a quart of cider each day, two took vitriol three times daily, two took two spoonfuls of vinegar daily, two were given seawater and two were given dietary supplements. The remaining two were each given two oranges and one lemon every day. ‘The most sudden and visible effects were perceived from the use of oranges and lemons one being at the end of six days fit for duty and the other appointed to attend the rest of the sick’.
(Dr James Lind’s Treatise on Scurvy, 1753)
Source: Adapted from Bhatt (19).
Table 1.1 A light‐hearted perspective on alternatives to evidence‐based medicine.
Source: Adapted from Straus et al. (3).
Evidence‐based medicine – relies on the randomised controlled trial and the systematic review
Eminence‐based medicine – the precedence of seniority of years in making the correct decision
Vehemence‐based medicine – the stridency with which one makes one’s own beliefs known
Eloquence‐based medicine – the ability of ensuring one’s views prevail given an ability to explain them beautifully
Diffidence‐based medicine – accepting the inevitability of the natural history of the patient’s disease
Nervousness‐based medicine – practising with the aim of avoiding complaint or litigation
The philosophy of evidence‐based healthcare (4)
Healthcare is about diagnosis but at least as importantly about management including treatment and intervention. Historically, three approaches have been taken. Firstly, the impact of expertise and experience allied to mechanistic reasoning (‘In my experience, from the patients I have seen…’). There is also the approach that any treatment can only be deemed curative if the precise mechanism is known and understood. The final approach, advocated in evidence‐based healthcare, is that the effects of a medical intervention are best evaluated by direct observation of the effects by comparing groups as similar as they can be – one which has received the intervention and one which has not. All the aforementioned constitute evidence, but a hierarchy of evidence exists (Figure 1.1) (4):
Figure 1.1 Simplified hierarchy of evidence (systematic review of all study types is assumed to be superior to single studies).
Source: Howick (4)/John Wiley & Sons.
Randomised trials (RCTs) or systematic reviews of many randomised trials offer stronger evidential support than observational studies.
Comparative clinical studies in general (including both RCTs and observational studies) offer stronger evidential support than mechanistic reasoning from more basic sciences.
Comparative clinical studies in general (including both RCTs and observational studies) offer stronger evidential support than expert clinical judgement.
The first decades of evidence‐based healthcare have seen this approach become well established across clinical practice. At the same time, other themes have also emerged which were not initially considered (Chapter 9). For example, the perspectives of the patient and practitioner are both important in translating evidence into practice, and qualitative evaluation of these perspectives is also required. Moreover, clinical experience and expertise remain important, particularly in the realm of integrating policy, resources and shared decision‐making with patients. Finally, though the robustness of study design and reporting has improved, historically marginalised and underserved populations remain under‐represented in research participation. This limits the wider application of evidence into practice.
The origins of the evidence‐based healthcare movement
The ‘Evidence‐Based Medicine’ movement was launched in the early 1990s by a group of epidemiologists at McMaster University, Hamilton, Canada. The aim was a new paradigm of medical practice. Proponents advocated greater reliance on published data with evidence from clinical trials considered superior to mechanistic reasoning and clinical judgement (5). The concept of hierarchies of evidence developed during the 1970s (6). This culminated in 1981 with the publication of a series of articles in the Canadian Medical Association Journal on how to appraise the medical literature (7). While the principles of evidence‐based medicine were quickly accepted into practice, nonetheless there was concern about restriction of clinical judgement, ‘cookbook medicine’ and use of evidence‐based medicine by policymakers to implement cost‐cutting measures. These concerns were rebutted by the authors in an excellent BMJ article published in 1996, which stated (8):
‘Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence in making care about the care of individual patients’.
Furthermore, the authors were clear that this meant integrating the best available evidence from systematic research with individual clinical expertise and that this increased expertise arises from effective and efficient diagnosis in combination with thoughtful identification and compassionate use of individual patients’ predicaments, rights and preferences in decisions about their care. In the opinion of the authors, clinically relevant research may be from the basic sciences but especially from patient‐centred research, including diagnostic accuracy, prognostic markers and the efficacy and safety of therapeutic, rehabilitative and preventive management (8). While well‐conducted clinical trials and systematic reviews represent particularly high‐quality research, this does not invalidate other well‐designed studies if they are relevant and appropriate to the patient’s presenting problem. This correlates all the areas from which clinical questions from both patients and practitioners are likely to arise and which reflect the domains of evidence‐based healthcare:
Aetiology/harm (causation)
Prevention
Diagnosis
Therapy (treatment)
Prognosis
Meaning (patient’s experiences)
Using evidence at the bedside
Healthcare is a high‐pressure, time‐limited activity which relies on the interaction and co‐operation of all team members for the safety of the patient. This is facilitated by the availability of evidence. A feasibility study in 1995 at the University of Oxford, UK, concluded that making evidence available quickly to busy clinicians increased evidence‐seeking and the incorporation of evidence into patient care decisions (9). An ‘evidence cart’ was taken on clinical rounds (Figure 1.2). On average, two to three questions arose for each patient. It took between 15 and 90 seconds to find relevant evidence (9). Evidence was found most quickly using a resource of pre‐appraised topics, followed by use of Best Evidence with a Medline search taking the longest. Evidence changed management in one‐third of patients (Table 1.2).
The development of tablets and handheld devices has overcome the practical challenges of a ‘cart’. Clinicians are now used to retrieving evidence from their devices, even in front of patients. It is considered in the interests of patient safety and presents a cultural change from the perception the doctor must already know everything and be seen to already know everything. The development of pre‐appraised sources and guidelines facilitates this, though time is still a limiting factor. Even so, evidence‐based healthcare is not simply looking up evidence and what to do. Evidence must be assimilated and reasoned through even within the few seconds it takes to make a clinical decision. This approach needs to be embedded in training curricula – both undergraduate and postgraduate (Chapter 10). Use of evidence should permeate the whole of the clinical assessment and management pathways, including the history and examination. Teaching and learning evidence‐based healthcare is not simply critical appraisal. It needs to be taught imaginatively to engage learners, and it should relate to their current experience. The content of healthcare courses should reflect the best evidence and how to apply it rather than simply where to find it. Learners should have the opportunity to apply evidence to patients they have encountered under supervision and receive feedback on their progress.
Figure 1.2 David Sacket demonstrating the evidence cart.
Source: Straus et al. (10)/with permission of Sage Publications.
Table 1.2 Impact of the evidence cart.
Source: Adapted from Sackett and Straus (9).
81% – affected diagnosis and/or treatment
52% – confirmed current or tentative diagnostic or treatment plans
25% – led to new diagnostic skills, additional tests and new management decision
23% – corrected previous clinical skill, diagnostic test or treatment
The perceived need for evidence was high, but search was done in only 12% of patients
The achievements of evidence‐based healthcare
Evidence‐based healthcare has been forefront in the development of healthcare over the past 30 years. Its launch coincided with the growth of clinical guidelines. Guidelines have become influential in disseminating research evidence to frontline practitioners. The rigorous application of study design and reporting standards to medical research is essential in bringing structure and quality to the explosion of information and knowledge available via the internet. Ensuring treatments and interventions are applied only once they are rigorously and scientifically evaluated is essential in reducing patient harm and the overuse of technologies. The promotion of RCTs and systematic literature reviews (SLRs) has been both instrumental in focusing medical progress in interventions, treatments and devices firmly on an evidence base.
A particular achievement is the Cochrane Collaboration (Box 1.4). Founded in the United Kingdom and sponsored by the UK Department of Health, it has grown to an organisation of over 40 000 volunteers from over 190 countries responsible for producing over 400 systematic reviews each year on a wide range of medical treatments. Cochrane’s members and supporters include researchers, health professionals, patients and carers. Worldwide 3.66 billion people have point‐of‐use access to the library (11). Over 7500 systematic reviews have been published by the Cochrane Library, where they are downloaded over 12.5 million times each year (Tables 1.3 and 1.4) (11).
Medical knowledge is more readily available to patients and non‐clinicians. Healthcare practitioners are expected to share their knowledge in collaboration with patients in management. These conversations need to be evidence‐based. Integrating evidence with clinical communication to share decision‐making with patients is a recognised domain of clinical reasoning applicable in many areas of practice (12–14). Evidence‐based practices consistently improve patient outcomes and returns on investment for healthcare providers (15).
Box 1.4 The Cochrane database of systematic reviews
The Cochrane Library is an international research network made up of several databases relating to biomedical research and associated economic analyses. The Cochrane Database of Systematic Reviews (CDSR) is an online repository of high‐quality systematic reviews covering a wide range of topics. Cochrane reviews all follow guidelines for research methods relating to research question scope, systematically collecting evidence, assessing bias, statistical analysis and performing meta‐analyses of amalgamated datasets. These guidelines are free to view online at https://training.cochrane.org/handbooks. The full texts of completed systematic reviews are freely available on the CDSR due to the Cochrane Library’s commitment to open‐access research. Protocols of completed and ongoing systematic reviews are also freely available and are a useful source for those wanting to better understand research methods for literature reviews.
Author: Alistair Hewins, Final Year Graduate Entry Medical Student, University of Nottingham, UK
Table 1.3 Types of review published by the Cochrane Library.
Intervention review
Assess the effectiveness/safety of a treatment, vaccine, device, preventative measure, procedure or policy
Diagnostic test accuracy review
Assess the accuracy of a test, device or scale to aid diagnosis
Prognosis review
Describe and predict the course of individuals with a disease or health condition
Qualitative evidence syntheses
Investigate perspectives and experiences of an intervention or health condition
Methodology reviews
Explore or validate how research is designed, conducted, reported or used
Overviews of reviews
Synthesise information from multiple systematic reviews on related research
Rapid reviews
Are systematic reviews accelerated through streamlining or omitting specific methods
Prototype reviews
Include other types of systematic review that do not yet have established standard methodology in Cochrane, such as scoping reviews, mixed‐methods reviews, reviews of prevalence studies and realist reviews
Author: Alistair Hewins, Final Year Graduate Entry Medical Student, University of Nottingham, UK.
Table 1.4
