The Doctor’s Guide to Critical Appraisal

350 Pages·2015·2.95 MB·English

by  Narinder Gosall & Gurpal Gosall

THE DOCTOR’S GUIDE
TO CRITICAL APPRAISAL
FOURTH EDITION
THE DOCTOR’S GUIDE
TO CRITICAL APPRAISAL
FOURTH EDITION
Dr Narinder Kaur Gosall
BSc (Hons) PhD
Lead Tutor, The Critical Appraisal Company
Director, Superego Cafe Limited
Dr Gurpal Singh Gosall
MA MB BChir MRCPsych
Consultant General Adult Psychiatrist
and Foundation Program Lead,
Lancashire Care NHS Foundation Trust
Director, Superego Cafe Limited
© 2015 PasTest Ltd
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All rights reserved. No part of this publication may be reproduced, stored in a retrieval system,
or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording
or otherwise without the prior permission of the copyright owner.
First edition 2006, Second edition 2009, Third edition 2012, Fourth edition 2015
ISBN: 978 1 905635 979
ePub ISBN: 978 1 909491 915
Mobi ISBN: 978 1 909491 908
A catalogue record for this book is available from the British Library.
The information contained within this book was obtained by the authors from reliable sources.
However, while every effort has been made to ensure its accuracy, no responsibility for loss,
damage or injury occasioned to any person acting or refraining from action as a result of
information contained herein can be accepted by the publisher or the authors.
This book contains excerpts from clinical papers. The content and formatting of these excerpts
may have been altered for teaching purposes. All excerpts are taken from Open Access articles
distributed under the terms of the Creative Commons Attribution License (2.0–4.0), which
permits unrestricted use, distribution, and reproduction in any medium, provided the original
work is properly cited. No endorsement or criticism of the researchers is implied by the
inclusion of the excerpts in this book
All characters appearing in the scenarios are fictitious. Any resemblance to real persons, living
or dead, is purely coincidental. All the clinical scenarios are for teaching purposes only and
must not be used to inform clinical practice.
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CONTENTS

About the authors
Introduction to the fourth edition
Acknowledgements
SECTION A – EVIDENCE-BASED MEDICINE
Introducing critical appraisal
Formulating a question
Search strategies
The journal
Organisation of the article
SECTION B – AIMS AND OBJECTIVES
The clinical question
Subgroup analysis
Introducing confounding
Introducing bias
SECTION C – STUDY DESIGNS
Overview
Observational descriptive studies
Observational analytical studies
Experimental studies
Other types of studies
Research pathway
SECTION D – SELECTING SUBJECTS
Overview
Populations and samples
Selection bias
Matching
Randomisation
Concealed allocation
Propensity scoring
Baseline characteristics
SECTION E – OBSERVING SUBJECTS
Overview
The effects of expectation
Observation bias
Blinding
Endpoints
Validity
Reliability
Bias revisited
SECTION F – INTERPRETING RESULTS
Overview
Basic statistical terms
Epidemiology
Types of data
Measuring data
Data distributions
Summarising categorical data
Summarising normally distributed data
Summarising non-normally distributed data
Inferring population results from samples
Patient flow
Comparing groups – risks and odds
Comparing groups – the null hypothesis
Comparing samples – statistical tests
Correlation and regression
Interim analysis
Non-inferiority and equivalence trials
Confounding revisited
SECTION G – CHECKLISTS
Introduction to checklists
Aetiological studies
Diagnostic or screening studies
Treatment studies
Prognostic studies
Economic studies
Qualitative research
Guidelines
Systematic reviews and meta-analyses
Systematic reviews – homogeneity and heterogeneity
Publication bias
SECTION H – APPLICABILITY
The hierarchy of evidence
Critical thinking
SECTION I – CRITICAL APPRAISAL IN PRACTICE
Health information resources
Presenting at a journal club
Taking part in an audit meeting
Working with pharmaceutical representatives
Further reading
A FINAL THOUGHT
Dedicated to our son, Dilip, whose boundless energy and enthusiasm
for life is contagious.
ABOUT THE AUTHORS

Dr Narinder Kaur Gosall BSc (Hons) PhD
Lead Tutor, The Critical Appraisal Company
Director, Superego Cafe Limited
Narinder Gosall studied in Liverpool and gained a PhD in
neuropathology after investigating the role of the phrenic nerve in
sudden infant death syndrome and intrauterine growth retardation.
After working as a university lecturer she joined the pharmaceutical
industry. She worked in a variety of roles, including as a Medical
Liaison Executive and as a Clinical Effectiveness Consultant for Pfizer
Limited. She has extensive experience in teaching critical appraisal skills
to healthcare professionals and is an international speaker on the
subject. She is the Lead Tutor at The Critical Appraisal Company and
the editor of the online course at www.criticalappraisal.com.
Dr Gurpal Singh Gosall MA MB BChir MRCPsych
Consultant General Adult Psychiatrist and Foundation Program Lead,
Lancashire Care NHS Foundation Trust
Director, Superego Cafe Limited
Gurpal Gosall studied medicine at the University of Cambridge and
Guy’s and St Thomas’s Hospitals, London. He worked as a Senior
House Officer in Psychiatry in Leeds before taking up a post as
Specialist Registrar in the North West. He now works as a Consultant
General Adult Psychiatrist, looking after patients in the Psychiatric
Intensive Care Units at the Royal Blackburn Hospital and Burnley
General Hospital. He has a long-standing interest in teaching, design
and programming. He founded Superego Cafe, a medical education
company which runs courses and websites for psychiatrists.
www.superegocafe.com.