Handbook of Evidence-Based Veterinary Medicine

by Cockcroft, Peter; Holmes, Mark

• ISBN13: 9781405108904
• ISBN10: 1405108908
• Edition: 1st
• Format: Paperback
• Copyright: 2003-05-16
• Publisher: Wiley-Blackwell

Summary

The application of evidence-based veterinary medicine (EBVM) can assist in improving and optimising the diagnosis, prognosis, control, treatment and ultimately the welfare of animals. It can also provide the user with a methodology for appropriate, patient orientated life-long, self-directed, learning. To practise evidence-based veterinary medicine we require a range of skills that we may not have. This book will explain what evidence-based veterinary medicine is and show how it can be applied to veterinary practice to improve the quality of care for patients and provide informed choices for owners. It will provide the reader with a toolkit of skills necessary to practise evidence-based veterinary medicine. This book is aimed at practitioners but will be of interest to veterinary surgeons at any stage of their training or career wishing to learn about EBVM.

Author Biography

The authors are responsible for devising and teaching an EBVM course at the veterinary school at Cambridge.

Dr Peter Cockcroft, Clinical lecturer, Department of Clinical Veterinary Medicine, University of Cambridge.

Dr Mark Holmes, Senior lecturer in Preventive Veterinary Medicine, Department of Clinical Veterinary Medicine, University of Cambridge.

Table of Contents

Preface	xiii
Acknowledgements	xiv
Introduction	1	(22)
Who is this book for?	2	(1)
Who isn't this book for?	2	(1)
What do we mean by EBVM? A brief description	3	(1)
Comparison of the traditional methods and EBVM	4	(1)
Why should we practise EBVM?	4	(7)
Because we can	4	(1)
Because our clients can too	5	(1)
We need the information	5	(3)
Time for learning, a diminishing resource faced with expanding demands	8	(1)
Increasing the speed of adopting the results of science	8	(1)
To better direct clinical research	9	(1)
Ethical aspects of proof	9	(1)
Ethical conduct in the absence of scientific evidence	10	(1)
A return to science	11	(1)
Are we ready to ask questions about our own performance?	11	(1)
A more detailed description of EBVM	11	(3)
The process	11	(2)
The need for evidence	13	(1)
Other sources of information and evidence	14	(1)
EBM in human medicine	14	(1)
EBM in veterinary medicine	15	(1)
Are we already practising EBVM?	16	(1)
EBVM case studies	16	(3)
Small animals: megavoltage radiotherapy of nasal tumours in dogs	16	(1)
Farm animals: restocking after foot and mouth disease	17	(1)
Horses: efficiency of prednisolone for the treatment of heaves (COPD)	18	(1)
How this book is organised	19	(4)
The aims and objectives of this book	19	(1)
Outline of the structure of this book	19	(1)
References and further reading	20	(2)
Review questions	22	(1)
Turning Information Needs into Questions	23	(11)
Introduction	24	(1)
Refining clinical questions so that evidence can be found	24	(1)
Is this a good treatment for a disease?	24	(1)
How good is a test?	24	(1)
Four main elements of a well-formed clinical question	25	(1)
Patient or problem	25	(1)
The diagnostic or therapeutic intervention, prognostic factor or exposure	25	(1)
Comparison of interventions (if appropriate or required)	25	(1)
The outcome	26	(1)
Categorising the type of question being asked	26	(1)
Prioritising the questions	26	(1)
Checklist of information needs	26	(4)
Epidemiological risk factors	27	(1)
Diagnostic process	27	(1)
Treatment	28	(1)
Harm/aetiology	29	(1)
Prognosis	29	(1)
Control (risk reduction) and prevention (risk avoidance)	30	(1)
Potential pitfalls in constructing questions	30	(1)
Complexity of the questions	30	(1)
The need for sufficient background knowledge	31	(1)
More questions than time	31	(1)
Realistic targets for veterinary practice	31	(1)
Evidence of quality control	31	(3)
Further reading	32	(1)
Review questions	33	(1)
Sources of Information	34	(21)
Introduction	35	(1)
Background and foreground knowledge	35	(1)
Hierarchy of evidence	35	(2)
Important traditional information resources	37	(3)
Journals	37	(2)
Textbooks and other review type publications	39	(1)
Personal experience and background knowledge	39	(1)
Colleagues	40	(1)
Practice records	40	(1)
The Internet	40	(2)
Veterinary information resources on the Internet	42	(9)
CABdirect	42	(1)
Consultant	43	(1)
Inno-vet	43	(1)
International Veterinary Information Service	43	(1)
Medline/Pubmed	44	(4)
The Merck Veterinary Manual	48	(1)
Montreal Veterinary School	48	(1)
NetVet and the Electronic Zoo	49	(1)
RCVS and RCVS library	50	(1)
VetGate	50	(1)
VIN	50	(1)
Wildlife Information Network	51	(1)
Other computer-based information resources	51	(2)
BSAVA	52	(1)
CLIVE	52	(1)
Lifelearn	52	(1)
Vetstream	52	(1)
Critically appraised topics	53	(2)
Further reading	53	(1)
Review questions	54	(1)
Searching for Evidence	55	(12)
Introduction	56	(1)
RCVS library	56	(1)
Other online book catalogues	56	(1)
Consultant	57	(1)
Searching strategies: simple Boolean logic	57	(1)
Using Pubmed	58	(2)
Sensitivity and specificity	60	(1)
Special veterinary considerations	60	(1)
Searching for the answers to questions about therapy	61	(1)
Searching for the answers to questions about diagnosis	62	(1)
Searching for the answers to questions about aetiology	62	(1)
Searching for the answers to questions about prognosis	62	(1)
Using the `Clinical Queries' option in Pubmed	63	(1)
Depth of the veterinary scientific literature	63	(2)
Developing searching skills	65	(2)
References and websites	65	(1)
Review questions	66	(1)
Research Studies	67	(17)
Hierarchy of evidence and experimental design	68	(1)
Guide to research methods	69	(1)
Literature reviews	69	(2)
Systematic reviews	70	(1)
Meta-analyses	70	(1)
Experimental studies	71	(2)
Randomised controlled trials	71	(2)
Cross-over designs	73	(1)
Observational studies	73	(5)
Cohort studies	74	(1)
Cross-sectional survey	75	(1)
Case-control studies	76	(2)
Diagnostic tests and screening tests	78	(1)
Poorly controlled or uncontrolled trials	78	(1)
Comparisons between groups at different times	78	(1)
Comparisons between different places	78	(1)
n = 1 trials (the `treat and see' method)	79	(1)
Uncontrolled trials (before and after trials)	79	(1)
Non-random allocation trials	79	(1)
Descriptive studies	79	(5)
Surveys	79	(1)
Case series and case reports	80	(1)
Further reading	81	(1)
Review questions	82	(2)
Appraising the Evidence	84	(23)
Some introductory concepts	85	(3)
The importance of statistics	85	(1)
Likelihood: probability and odds	86	(1)
Risk and uncertainty	87	(1)
Appraising articles on veterinary therapy	88	(5)
Is the study valid?	88	(2)
Are the results important?	90	(1)
Quantifying the risk of benefit or harm	90	(2)
Confidence intervals (CIs)	92	(1)
Making a decision about therapy	93	(1)
Appraising articles on veterinary diagnosis	93	(5)
Is the study valid?	94	(1)
Are the results important?	95	(3)
SpPin and SnNout	98	(1)
Making a decision about a diagnostic test	98	(1)
Appraising articles on harm or aetiology	98	(4)
Is the study valid?	100	(1)
Are the results important?	101	(1)
Statistical analysis	102	(1)
Appraising studies on prognosis	102	(5)
Is the study valid?	103	(1)
Are the results important?	104	(1)
References and further reading	104	(1)
Review questions	105	(1)
Solution to the probability example used in Section 1	106	(1)
Diagnosis	107	(18)
Introduction	108	(1)
Definitions	108	(2)
Types of diagnosis	109	(1)
The clinical examination: evidence for the presence of disease	110	(1)
Hypothetico-deductive reasoning	111	(1)
The diagnostic process	112	(2)
Recall and ranking	114	(2)
Pattern matching	114	(1)
Probabilities	114	(1)
Pathophysiological reasoning (functional reasoning)	115	(1)
Which method of pattern recognition is used?	116	(1)
Clinical reasoning strategies used in hypothetico-deductive reasoning	116	(2)
The properties of clinical signs	116	(1)
Logical exclusion of a disease	117	(1)
Inductive and deductive reasoning	117	(1)
Abstraction/aggregation	117	(1)
Prevalence	118	(1)
Errors in hypothetico-deductive reasoning	118	(1)
Logic, sets, Venn diagrams, Boolean algebra	119	(3)
Clinical sign sensitivities	120	(1)
Disease subsets	120	(1)
Venn diagrams and Boolean algebra	120	(2)
Clinical staging of metritis in cattle	122	(3)
References and further reading	122	(1)
Review Questions	123	(2)
Clinical Diagnostic Decision Support Systems (CDDSSs)	125	(29)
Introduction	126	(1)
Definition	126	(1)
Questions you should ask	127	(1)
Understanding the methodology used by CDDSSs	127	(4)
Logic	128	(1)
List matching	129	(1)
Probabilities (Bayes' rule)	129	(1)
Knowledge-based systems incorporating symbolic reasoning (syntactical systems)	130	(1)
Bayesian belief networks	131	(1)
Neural networks	131	(1)
Sources of uncertainty or inaccuracies	131	(1)
Evaluation of the performance of CDDSSs	132	(1)
Which is the best method to measure the performance of a CDDSS?	132	(1)
Alternative desirable indicators of performance using accuracy	133	(1)
Veterinary diagnostic decision support systems	133	(16)
A decision support algorithm for individual cow infertility	133	(1)
Consultant	134	(4)
Vetstream Canis	138	(1)
PROVIDES (Problem Orientated Veterinary Information and Decision System)	138	(3)
Bovid	141	(4)
EqWise	145	(1)
Cattle Disease Diagnostic System (CaDDiS)	146	(1)
Application of probability techniques to the objective interpretation of veterinary clinical biochemical data	147	(2)
Sources of information of the CDDSSs described in this chapter	149	(5)
Further reading	151	(1)
Review questions	152	(2)
Decision Analysis, Models and Economics as Evidence	154	(28)
Introduction	155	(1)
Decision analysis	155	(2)
Methods for clinical decision making	155	(1)
Situations in which decision analysis may be helpful	156	(1)
The five steps in decision analysis	156	(1)
Disadvantages of decision analysis	157	(1)
Decision trees	157	(12)
Utilities	158	(1)
Solving the decision tree	158	(1)
Sensitivity analysis	158	(1)
Missing options	158	(1)
Helping owners decide	159	(1)
Obtaining utility values from clients and owners	160	(1)
Decision analysis tree for therapeutic decisions	161	(1)
Decision analysis tree for economic decisions	161	(2)
Decision analysis tree of diagnostic tests	163	(3)
Pay-off tables	166	(3)
User checklist for clinical decision analysis	169	(1)
Testing and treating thresholds	169	(2)
General properties of testing and treating thresholds	170	(1)
Modelling	171	(5)
Modelling herd infection dynamics	172	(2)
Modelling and the control of foot and mouth disease	174	(1)
Modelling Staphylococcus aureus infection in a herd	175	(1)
User guide to models	175	(1)
Economic analysis	176	(2)
Partial budgets and cost--benefit analysis	176	(2)
User guide to economic analysis	178	(1)
Medline search functions	178	(4)
References and further reading	178	(2)
Review questions	180	(2)
EBVM: Education and Future Needs	182	(8)
EBM in medical education	183	(1)
Resources for the practice of EBM	183	(2)
Critically appraised topics (CATs)	183	(1)
High quality systematic reviews	183	(1)
The Cochrane Library	184	(1)
Secondary journals (e.g. EBM)	185	(1)
EBM in veterinary education	185	(1)
Evidence-based veterinary toolkit	185	(1)
Finding out what is in the literature and what is not in the literature	185	(1)
What resources do we need for the practice of EBVM?	185	(1)
Clinical (EBVM) audits in veterinary practice	186	(1)
What is a clinical audit?	186	(1)
Why do we need a clinical audit?	186	(1)
What has a clinical audit got to do with EBVM?	186	(1)
How do we carry out an EBVM audit?	186	(1)
Clinical audits and the future	187	(1)
Other future developments	187	(3)
References and further reading	188	(2)
Glossary of Terms Used in EBVM	190	(11)
Bibliography	201	(3)
Answers to Review Questions	204	(2)
Index	206