Evidence-Based Veterinary Medicine PDF

Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com Evidence-based veterinary medicine: translating the results of research into improved patient care Evidence-based veterinary mmedicine 1. Why is it important and what MARK HOLMES AND PETER COCKCROFT skills are neede...

Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com Evidence-based veterinary medicine: translating the results of research into improved patient care Evidence-based veterinary mmedicine 1. Why is it important and what MARK HOLMES AND PETER COCKCROFT skills are needed? THIS is the first part of a series of three articles on evidence-based veterinary medicine (EBVM) - a discipline which increasingly is being recognised as having a fundamental role to play in day-to-day veterinary practice, as well as being vital to the future development of the profession. The article defines what EBVM is, explains its importance and describes the range of skills required to practise EBVM. Parts 2 and 3, which will be published in the February and March issues, respectively, will look in greater detail at first identifying information needs and searching for evidence, and then appraising the evidence. Mark Holmes graduated from THE ORIGINS OF EVIDENCE-BASED MEDICINE Cambridge in 1985 and is now a senior lecturer in preventive veterinary medicine at the University of Cambridge. He is a coauthor of the 'Handbook of Evidence-Based Veterinary Medicine', published by Blackwell Publishing, and is currently Honorary Secretary of the BSAVA. The roots of evidence-based medicine are as old as medicine itself. However, the current manifestation of evidence-based medicine orig inates from a group of clinical epidemiologists working at McMaster- University in Canada in the late 1970s, led by David Sackett. These researchers used the termi'critical appraisal' to describe the application of basic rules of evidence when reading articles in clinical Journals. Gordon Guyatt. member of the McMaster group, introduced the form-lal teaching of evidence-based medicine into postgraduate medical training to emphasise a philosophy of medical practicc based on1 a knowledge anid understanding of the medical literature supporting each clinical decision. The paradigm shift to explicit use of evidence stems a the fundamental acknowledgemnent that we 'are and never can be. We introduce a healthy scepticism into our use of knowledge and attempt to Justify its use as evidence. This cvidence comes in many forms - clinical signs, history. labor(atory tests, lectur-e notes, textbooks, case reports, randomised controlled trials, opinions, and so on. Not only do we need to fiiid the evidence we need in order to make clinical decisions, we also need to be able to appraise that evidence. From the above, one can begin to appreciate that evidence-based medicine is a multifaceted beast that defies a glib or instantly accessible definition. In many cases, it requires the accumulation of new skills (or the reactivation of previously learnt skills) and the use of tools to enable the clinician to find, appraise and apply evidence to the care of patients. from never certain Peter Cockcroft graduated from Cambridge in 1980. He is a lecturer in farm animal medicine at the University of Cambridge and holds the RCVS Diploma in Cattle Health and Production. He is a coauthor of the 'Handbook of Evidence-Based Veterinary Medicine'. ..0. 0. .0. 28 - 0- 0 - 0 . 0 600 * - - 0. *. *. - 0 0. - . -. .0 - . 0= * .0 - - * . 0 0 .0.0. =0 0. 0 .0. 0- . . 0 - -0. .0 . = - . 0 0 0= 0 00 WHAT IS EVIDENCE-BASED VETERINARY MEDICINE? At first glance, there would be no reasoni to believe that veterinary version of evidence-based medicine should be any different from that used by our miledical colleagues. Hovever. it is clear that the evidence and resources enjoyed by practitioner-s of human medicine are considerably greater- than those that are available to us. Furthermiiore, the pressures and constraints on veterinary practice ar-e dlifferent in many respects. The v.alue of evidence derived from clinical trials is directly propoi-tional to the statistical power of the study; in other words, the probability of an effect actually being detected by that study. (For example, in a recent study investigating the ability of a homeopathic remedy to reduce the somiiatic cell count in milk in a 250-cow herd, the power of the study predicted that there wvas a 71 per cent chance of detecting a reduction of 30 per cent. Ideally, the power should be 80 per cent or greater.) This allows the construction of a hierarchy of evidence, based on the strengths of differ-ent study designs, to answver specific research questions. A typical representation of this hierarchy is the so-called 'pyramid of a In Practice e JANUARY 2004 Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com evidence' (see right). Clinical decisions in human medicine can usually be made on the basis of evidence present within the hierarchy shown in the pyramid on the left of the diagram. However, much decision-making in veterinary medicine would rely on evidence that falls within the right-hand pyramid; this hierarchy is less easy to establish and its appraisal is more difficult. That said, each rationally made clinical decision is made on the basis of some evidence - and this evidence may be ranked, albeit subjectively in many cases. Stronger evidence A Case series Single case reports /Editorials, opinions, consensus rep Comparative animal research I ertificate holder opinion ie In vitro 'test tube research' WHY IS IT IMPORTANT? Given the difficulties, one option might simply be to dismiss evidence-based medicine as being impractical in the veterinary context. However, like democracy and apple pie, the essence of evidence-based medicine is clearly a good thing. We all have some knowledge of clinical epidemiology and an understanding of how it could improve our practice of veterinary medicine, but why should we seek to continually improve the methodology and process of EBVM? Because we can Developments in information technology have made EBVM possible. We no longer have to keep a card index of interesting papers or need access to veterinary school libraries in order to search the literature. With access to the Internet it is possible to search through millions of papers in a matter of seconds and, having located a paper of interest, to obtain a copy within a minute or two. Access is virtually free and geographical distance is no barrier. Because our clients can, too Almost all of the tools that enable us to locate the evidence we need are also available to our clients (and their lawyers). In instances where clinical decisions are questioned by clients - following, say, a poor outcome - it is important to be able to account for those decisions. There will always be enormous scope and need for clinical judgement, but, where possible, this should be backed up by the best scientific evidence. Effective communication of the evidence helps clients to make informed decisions and avoid unrealistic expectations. We need the information Broadly speaking, information needed to solve a problem falls into three categories: * Information that is needed and is known; * Information that is needed but is not known; * Information needs that are not recognised. With the volume of new information growing year on year, it is becoming impossible to keep up to date with all developments. Veterinary surgeons cannot realistically be expected to remember everything they need in order to practise, as only the most commonly used information is readily available from memory. Shaughnessy and others (1994) proposed the following formula for determining the usefulness of information: Usefulness of medical = information Relevance x Validity Work to access The relevance of any information is based on the frequency of exposure to the problem and the type of In Practice c JANUARY 2004 evidence being presented. Validity is the likelihood of the information being true. The work to access the information is the time and effort that must be spent to extract and analyse the information for the strength of evidence it provides. The ideal information source would be directly relevant, contain valid information, and be accessible with the minimum of effort. Time for learning is a diminishing resource, while demands are expanding The traditional approach to continuing professional development (CPD) involves attempting to predict what our information needs are, finding a source of that information, and then filing away the information ready for when it is needed. For example, you may become aware that there are new antibiotics on the market; you see a review article in a journal, or an advertisement for an antimicrobial therapeutics meeting; you learn that some drugs you haven't used before might be useful for certain cases; you wait until you next get a suitable case; and then you apply the new knowledge. The EBVM approach is to look for the information in response to information needs for individual cases. The phrase 'just in time knowledge', as opposed to 'just in case knowledge', has been used to describe the new approach to these information needs. Everything that is learnt in this way is directly relevant to your practice and the cases you see. Searching skills and appraising skills have to be learnt but, once acquired, enable the time devoted to CPD to be used to maximum effect. Results of research can be adopted more quickly The volume of veterinary literature is expanding inexorably, to the point that specialists and generalists alike can find it hard to keep up to date and retain this knowledge. But why wait for a secondhand version of the information to be described in a book chapter several years after the publication of the results of a clinical trial? The abstract of a trial will be available on the Internet within days of publication; the paper itself will be available online, or via the RCVS Library. It is exciting and rewarding for veterinary practitioners to apply their intellect and skills in delivering innovation to patients and their owners. The term 'research into practice' has become a dictum in human medicine. It helps to direct clinical research General practitioners are ultimately the consumers of clinical research. In the course of their day-to-day work, a veterinary clinician practising EBVM will generate a large number of information needs but, unlike his or her medical colleagues, will find many of them unanswered in the 29 / a Textbook information Internetderived Non-veterinary information expertise Evidence may be arranged hierarchically to form a ,pyramid of evidence'. In veterinary medicine, much of the evidence used is shown in the pyramid on the right. It may be difficult to appraise such information; however, it often reveals where there is a lack of evidence. Practitioners have an important role to play in identifying information deficits and performing clinical research. RCTs Randomised controlled trials Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com S*fs0ss.ls^wluir<<ElilrnralWsT, zi r'.S- *S.^s;<.,f {4.] {l,., 1s 1 {ls.rx ralil 4 xfwl _ 0 Category Species Question Source of evidence Information before evaluation of usefulness Diagnosis Cattle How good is the ELISA for detecting subclinical Johne's disease? Smith and Slenning (2000) Sensitivity: 45% Specificity: 99% Cat How good is my in-house test for FIV and FeLV? Hartmann and others (2001) six tests compared Sensitivity ranges: FIV 43-97%, FeLV 52-91 % Specificity ranges: FIV 97-100%, FeLV 92-99% Dog What is the antibiotic of choice for treating pyoderma? Holm and others (2002) No resistance to penicillinase-stable (3-lactams in 384 isolates reported Dog Do need to give perioperative prophylactic antimicrobial therapy when performing elective orthopaedic surgery? Whittem and others Infection rates: with antibiotics 4/91 (4%), without antibiotics 5/35 (14%) Horse Is prednisolone as good as dexamethasone for acute recurrent airway obstruction? Robinson and others (2002) Clinical improvement after 3, 7 and 10 days: parenteral dexamethasone 8/9, 8/9, 8/9; oral prednisolone 0/9, 0/9, 5/9 Cat and dog How quickly are adult fleas killed following the application of fipronil (Frontline Spot On; Merial)? Schenker and others (2003) Cats: 3 hours (24%), 8 hours (63%) Dogs: 3 hours (36%), 8 hours (47%) Cattle What is the probability of a downer cow recovering if it has been down for four days? Shpigel and others (2003) Day 1 76%; Day 2 31 %; Day 3 31 %; Day 4 19% How often do haemangiopericytomas recur following surgical removal? Mazzei and others (2002) 18 cases, two-year follow-up: 22% dead (recurrence or metastases); 78% alive (67% normal, 110% recurrence) Cat How successful is renal transplantation in cats with end-stage renal failure? Mathews and Gregory (1997) 66 cases: 29% died perioperatively, 17% died of unrelated causes, 26% died of related causes (median survival 12 months, mean survival 15 months); 28% alive (median survival 22 months, mean survival 26 months) Horse What is the probability of death in horses undergoing procedures requiring general anaesthesia? Johnston and others (1995) 6255 cases reported, with an overall mortality of 166% Treatment Prognosis Dog Risk primary scientific literature. For some, this might be (1 999) a t-ea- to dismiss the use of EBVM. However, by adopting EBVM, practitioners would soon identify the major areas of deficiency and be able to provide evidence that clinical son research is needed in these areas. For those involved in performing, funding or directing clinical research, this input would be of enormous benefit in determining what \as needed in 'the real wvorld'. effective treatments are provided, and this r-aises the salient qLlestion of, 'How do we know that a treatmenit is safe (and effective?'. Within our professioni, are we prepared to accept some responsibility as individuals? We rely entirely on expert opinion or analysis, or we can be prepared to look at the primary evidence ourselves. can WHAT SKILLS ARE NEEDED? Ethical aspects of proof The veterinary profession has contract with society. We are permitted to operate 'closed shop' in providing, a a veterinary treatment, and in return we promise to ensure certain levels of competence and to adhere to certain ethical standards. We are awarded powers that are not given to the wider public, and with those powers come responsibilities. A veterinary surgeon has a moral and ethical obligation to provide treatment for which there is good evidence of efficacy. Our clients expect that safe and What skills do I need? The ability to: * Turn information needs into questions * Find sources of evidence * Search for evidence * Appraise the evidence * Make clinical reasoning explicit An understanding of: * Types of research studies * Clinical decision support systems * Decision analysis, models and economics, as evidence * Quality control and clinical audits 30 In EBVM, reduced reliance is placed on intuition. unsystematic clinical experience, and pathophysiological assumptions as a basis for clinical decision-making, and is instead placed on evidence from randomised contr-olled trials or accurate recording of information. Meta-analyses, which statistically summarise the results of number of randomised controlled trials. are increasingly being used as a source of evidence. Evidence-based medicine is the enhanicement of a cliniician's traditional skills in diagnosis, treatment, preventioni and related areas through the systemnatic framing of relevant and answverable questions and the use of mathematical estimates of probability and risk. Surveys in human medicine indicate that clinical decisions are only rarely based on best evidence. Decisionmaking is often heavily influenced by anecdote (personal clinical experiences) and distortion of prevalence or outcomes. Decision-making by referring to expert opinion ('eminence-based medicine') assumes evidence-based decisions, but this may not always be the case. The best evidence is derived from clinically relevant research, especially patient-centred clinical research into diagnostic tests (including clinical examination), the predictive value of prognostic markers, Cand the efficacy Cand safety of therapeutic and preventative regimes. New evidence from clinical research may invalidate previously emphasis a In Practice JANUARY 2004 Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com accepted tests and treatments and identify more powerful, more accurate, more efficacious and safer procedures as replacements. However, EBVM requires additional skills and an understanding of statistical terms, and comes with a time cost. Such skills include the ability to translate practical information needs into questions that can be answered, as well as to devise and implement an efficient strategy to obtain available scientific evidence to answer the question; in addition, knowledge and skills are required to determine which of the available evidence sources are the most valid and appropriate. In their handling of clinical cases, veterinary practitioners are constantly performing a range of associated clinical tasks, such as: * Interpreting diagnostic tests; * Judging the efficacy of preventative or therapeutic interventions; * Trying to predict the harm associated with specific therapies; * Predicting the course and prognosis of the disease; * Estimating the costs of the intervention. In approaching these various tasks, clinicians need to know whether their procedures and judgements are valid. The practice of EBVM identifies the clinically important information required. The process is described in the box above. Other sources of information and evidence If relevant scientific evidence is lacking, clinical experience may provide the only evidence. However, memory is selective and not unbiased. Systematic, reliable, and reproducible recording of observations will provide better information than unquantified experience and EBVM - the process * Information needs are translated into a series of questions * A search is performed for the best available evidence with which to answer the question with maximum efficiency * The evidence obtained is critically appraised for its validity (closeness to the truth) and usefulness (clinical applicability) * The results of this appraisal are used in forming clinical judgements and determining actions * The outcome of the resulting decisions and actions is evaluated intuition. Systematic, accurate data recording and appraisal of this information is thus an important part of EBVM. Good examples include dairy farm recording of lameness, fertility and mastitis. THE FEASIBILITY OF EVIDENCE-BASED VETERINARY MEDICINE EBVM and evidence-based medicine are very closely related and differ principally in terms of the volume of available evidence. In veterinary science, the literature base is much smaller than that available to the medical profession (see table on page 33), and hence a rather broader approach is required. Restricting various sources of information from systematic research may omit potentially useful information which, on the one hand, may be difficult to validate but to which a weighting can be subjectively applied, thus enabling due emphasis to be placed on it. The human interpretation of evidence-based Important Internet resources rcvs.org.uk pubmed.org Pub ed I ., rubm .;jk Ll w11 2,6 Unf Welcome to the RCVS Library & of Medicne H - .. Psvph4m Hky I.., Chpbood Detok Information Service agwousty supporld by Notbook Laborstonta Limndad . Enteot or nm s amh tenns. of clickPrc.ie,o. Index for advanced searching. aulhor nantcs as smith jc. Initials are optional. . Enttr NorbrookQw te Pharmaceuticais Worldwide T', RCVS L.b.,Y&00g -rtlt*snSr)e!joee| t ,kAigE1 rlx h- tStY -norltil ColNqe,e -rtrlril bry d rs,vsdireo^ ttNe RoY. -dr'Al-Uoherm ,elth p-ot-, !o;0i roFes7 l<nl of Veteri-,t S-ge--t Enter ournal liltxc in fill or asIMEDLINE abbreviations. U.sc the Journals Dalabaos to find joumaaJ btles. PubMed. a service of the National Library of Medkine provides acces to over 12 mion MEDLINE otations back to the mid- I 96os and addOkonal life sctnce joumals. PubMed hdctdes links to many sites providing full lxt artdks and other related rources Ubtaty and infonnaaon tSnvces Joln te tibony and intormadon Sannice SSerh -h Cot4-cir -1t Updotr7 to RCVS ..dtta*s*s ."A. .- About tat Libtrty and tnfornenaon Sctite? top. .0.o.U d ttr .vott.1- RCItS L0.0. b C-1 Ne data nd tntrm--o S3rvi - h.lp tn 00-y additioal search Nwataitang an eareh ottons, selectiton have been added to See Otew5Nottort - Cibtbonst duing this adrtdes about Seyere Acte ResDot toov Svndomone (SARS) are provided .* of pesak inbredsttoIDhloitos.ar-hing this topic. UnS .. -pl.,.,. I. *The Summary pae dkoplays a v new Icn hnk for free funatl artiles PubMedn -- V-,. WV,.. - . o"W Tah 1R Gene luster, .ritten by Mary Carnngton and Paul Nonran is now aoadablae fotr interactive searching on the Bokshetl. 0.0.0 atr . (I., I".. 1.111W (PDF tt.l2KbW rrc How can you htap tea Uboray & Information tr- ' WCh.lw ttUrFY*Ilrnto WDcnr^ 0.0.. '. -.- .,. agm teadna The RCVS website Is a useful link to the RCVS Library & Information Service. The RCVS provides access to some full-text online versions of veterinary joumals to members of the College (user IDs and passwords can be requested from the RCVS). With easy public access to abstract databases, such as MEDLINE, one of the greatest obstacles to the practice of EBVM is getting access to joumals. Most practising veterinary surgeons do not have ready access to comprehensive libraries, but the RCVS Library through its reprint service and by providing online access goes some way towards meeting this need. There are also some useful links to evldence-based medicine and EBVM sites on the RCVS website In Practice e JANUARY 2004 Wn,te lo the H.1v Desk NCBI NLM NIH DeD.rtment ot Heaith S Human Servcice Freedom of Info-mtO.n Act DcIa MEDLINE is the electronic library of the United States National Library of Medicine. It contains over 10 million eitations and is generally considered to be the definitive source af medical evidence. Among the thousands of joumals for which it has abstracts are over 100 veterinary titles (including The Veterinary Record, Research in Voternnay Science, Veterinary Clinics of Morth America, and many others). MEDLINE is available free of charge through the Pubmed website. Pubmed provides a powerful tool for locating the relevant primary veterinary literature and, together with the RCVS Library, ensures that a practitioner should be able to find and read any papers ho or she requifes 31 Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com A simple way of assessing your own performance as an EBVM practitioner is to consider the following questions: * Do I identify and prioritise the problems to be solved (information needs)? * Do I perform a competent and complete examination to establish the likelihood of alternative diagnoses? * Do I have an accurate knowledge of disease manifestations, the sensitivities and specificities of clinical signs, and the frequency of occurrence of different combinations of signs within a disease(s)? * Do I search for the missing information? * Do I appraise the information in terms of scientific validity? * Do I understand the scientific terms, such as specificity and sensitivity, which will enable me to interpret the information provided? * Do I have the resources to access the Internet? * Am I making time available to access the Internet (and other sources of information)? * Am I aware of the veterinary information databases? * Is the application of new information scientifically justified, and intuitively sensible for this situation? * Do I explain the pros and cons of the different options, and take into account the different values (utilities) that the owner attaches to each outcome? Even avid EBVM practitioners will answer 'not always' to some of these questions, but an awareness of any deficiencies is the first step towards remedying them. medicine provides an ideal goal to aim for, but is currently too narrow in its definition for veterinary science. As evidence-based medicine developed much earlier than EBVM, an understanding of the former is invaluable in anticipating the future development of the latter. The main differences between the practice of EBVM compared with evidence-based medicine in the human field lie in the emphasis we necessarily place on evaluating poorer sources of evidence. The medical practitioner may dismiss a report of a single case as mere anecdote, whereas the veterinary practitioner may be grateful to have found a single published reference. In EBVM, the decision-making process is complicated by a variety of types of evidence; in turn, there is a greater need for us to understand how we make decisions to accommodate greater levels of uncertainty. As vets, we are placed in situations in which we handle more risk. The better Commun q management of this risk is a skill that we, our patients and our clients can benefit from. A FOCUS FOR THE FUTURE EBVM has been slow to develop as an independent discipline; a Pubmed search by the authors in December 2003 found 13,106 references to evidence-based medicine, but only 39 references to EBVM. However, there is a growing body of opinion that EBVM is vital to the future development of the profession. The lack of methodically performed, rigorous, large-scale clinical studies in veterinary medicine has been recognised by the Comparative Clinical Science Panel of the Medical Research Council. This organisation aims to provide a strategic focus for veterinary research, especially clinical the practice of EBM dit M How do I deal with patient (animal), owner and cost factors when formulating Investigationltreatment plans? The use of tools or methods to aid decision analysis is an important aspect of the practice of EBVM. They enable quantitative data, such as cost, as well as more subjective things, such as quality of life, to be factored in. There is a limit to how much can be covered in this article but more detailed information can be found in the veterinary and medical textbooks listed in 'further reading' on page 33. What happens when the evidence from a paper appears to contradict the view of an 'expert'? Obviously, in any given situation either the expert or the paper may be right. We don't often have the luxury of being able to talk to an expert in the consulting room, but instead can refer to reviews, textbooks or notes representing the view of the 'expert' at the time of writing. Sometimes the expert may be aware of more recent evidence or evidence that is more pertinent to the case in hand. Appraisal skills (to be covered in Part 3 of this series) should enable us to judge whether the evidence we find is both valid and relevant. 32 Is all th evidence I need in the primary literatre? It is likely that negative results are less likely to be published than positive results, for a variety of reasons. Indeed, many effective treatments have not been subjected to any scientific scrutiny. Nonetheless, veterinary practitioners will, almost without exception, be using some evidence when making clinical decisions. This evidence may just be that 'I learnt to do this when I was a student and it always seems to work'. Periodically we find ourselves in the same situation; we should question the decision and ask ourselves if further evidence has become available. Ideally, we would like to base our decisions on evidence from the top of the evidence pyramid, but we can often gather valuable evidence from other levels to help the xdecision-making process. It is possible that a randomised controlled trial produces a wrong result and that a 40-year-old textbook contains the right information. However, scientific methodology ensures that we know how confident we can be in the result of a properly conducted trial (a range of values within which we can be sure that the answer lies 19 times out of 20), whereas there is no objective method for assessing confidence in the results of treatments recommended by anecdote. In Practice C JANUARY 2004 Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com 0 0 Lel J, 1:1 .1 : " I ; f t 1 41 ML.xyl-.I I W-1I -1 4 :8 A ; tol J, a : I I -j J, 1 4 Question Dog Ca t Horse Cow Sheep Sensitive Specific 22,938 805 6725 237 3601 181 12,1 57 462 5987 203 Diagnosis Sensitive Specific 53,833 1246 22,604 11,769 40,417 19,161 539 458 2085 696 Aetiology Sensitive Specific 4364 267 1892 197 1280 136 2738 363 965 106 Prognosis Sensitive Specific 11,134 1090 5264 396 2496 341 9206 239 3978 139 Sheep Therapy This table shows the number of abstracts available from Pubmed (pubmed.org) using the Clinical Queries option for the major domesticated species. The sensitive search is a more exhaustive search which is likely to yield a number of irrelevant papers. The specific search is more focused, but is likely to overlook some papers of interest. These figures illustrate the size of the primary literature from which clinicians may obtain evidence. The data was collected in July 2002 rese.arch, to expand the evidcnce base for the pr.actice of veterinary medicine. A serious mcovemcnt towards EBVM will require that a large body of high quality, patient-centred research be av ailable to veterinaary surgeons willing, and able, to access and critically appralise the quality and applicability of clinical trials. Hantd in hand, there is ai requirement fori appropriate training resour-ces. As yet, thelr-e are no postgraduate tralining couLses, no specific journals and, at the time of xvriting, a singfle dedicated textbook. Although clinical students are encouraged to identify the best curren1t sources of information, the practice of esideuce-based medicine, the skill levels and the access to resouirces are largely unmeasured. Other references and further reading COCKCROFT, P. D. & HOLMES, M. A. (2003) Handbook of EvidenceBased Veterinary Medicine. Oxford, Blackwell Publishing SACKETT, D. L, STRAUSS, S. E., RICHARDSON, W. S., ROSENBERG, W. & HAYNES, R. B. (2000) Evidence-Based Medicine: How to Practice and Teach EBM. Edinburgh, Churchill-Livingstone SHAUGHNESSY, A. F., SLAWSON, D. C. & BENNETT, J. H. (1994) Becoming an information master: a guidebook to the medical information jungle. Journal of Family Practice 39, 489-499 -Example references HARTMANN, K., WERNER, R. M., EGBERINK, H. & JARRETT, 0. (2001) Comparison of six in-house tests for the rapid diagnosis of feline immunodeficiency and feline leukaemia virus infections. Veterinary Record 149, 317-320 HOLM, B. R., PETERSSON, U., MORNER, A., BERGSTROM, K., FRANKLIN, A. & GREKO, C. (2002) Antimicrobial resistance in staphylococci from canine pyoderma: a prospective study of first-time and recurrent cases in Sweden. Veterinary Record 151, 600-605 JOHNSTON, G. M., TAYLOR, P. M., HOLMES, M. A. & WOOD, J. L. (1995) Confidential enquiry of perioperative equine fatalities (CEPEF-1): preliminary results. Equine Veterinary Journal 27, 193-200 MATHEWS, K. G. & GREGORY, C. R. (1997) Renal transplants in cats: 66 cases (1987-1996). Journal of the American Veterinary Medical Association 211, 1432-1436 MAZZEI, M., MILLANTA, F., CITI, S., LORENZI, D. & POLI, A. (2002) Haemangiopericytoma: histological spectrum, immunohistochemical characterization and prognosis. Veterinary Dermatology 13, 15-21 ROBINSON, N. E., JACKSON, C., JEFCOAT, A., BERNEY, C., PERONI, D. & DERKSEN, F. J. (2002) Efficacy of three corticosteroids for the treatment of heaves. Equine Veterinary Journal 34, 17-22 SCHENKER, R., TINEMBART, O., HUMBERT-DROZ, E., CAVALIERO, T. & YERLY, B. (2003) Comparative speed of kill between nitenpyram, fipronil, imidacloprid, selamectin and cythioate against adult Ctenocephalides felis (Bouche) on cats and dogs. Veterinary Parasitology 112, 249-254 SHPIGEL, N. Y., AVIDAR,Y. & BOGIN, E. (2003) Value of measurements of the serum activities of creatine phosphokinase, aspartate aminotransferase and lactate dehydrogenase for predicting whether recumbent dairy cows will recover. Veterinary Record 152, 773-776 SMITH, R. D. & SLENNING, B. D. (2000) Decision analysis: dealing with uncertainty in diagnostic testing. Preventive Veterinary Medicine 45, 139-162 WHITTEM, T. L., JOHNSON, A. L., SMITH, C. W., SCHAEFFER, D. J., COOLMAN, B. R., AVERILL, S. M., COOPER, T. K. & MERKIN, G. R. (1999) Effect of perioperative prophylactic antimicrobial treatment in dogs undergoing elective orthopedic surgery. Journal of the American Veterinary Medical Association 215, 212-216 In Practice a JANUARY 2004 . _ _ . ._ 6- * -. 1 1 >; -66 . . 6 SS so - 6 S .5 0 :: 33 _ - Downloaded from inpractice.bmj.com on July 12, 2012 - Published by group.bmj.com Evidence-based veterinary medicine 1. Why is it important and what skills are needed? Mark Holmes and Peter Cockcroft In Practice 2004 26: 28-33 doi: 10.1136/inpract.26.1.28 Updated information and services can be found at: http://inpractice.bmj.com/content/26/1/28 These include: References Article cited in: http://inpractice.bmj.com/content/26/1/28#related-urls Email alerting service Receive free email alerts when new articles cite this article. Sign up in the box at the top right corner of the online article. Notes To request permissions go to: http://group.bmj.com/group/rights-licensing/permissions To order reprints go to: http://journals.bmj.com/cgi/reprintform To subscribe to BMJ go to: http://group.bmj.com/subscribe/