EBM Revisited: a brief refresher

2. EBM Revisited: a brief refresher Introduction and Description of the ADEPT Course Andrew Booth & Marishona Ortega

3. Why ADEPT? • librarians need to be able to support Evidence Based Healthcare • users need to be able to do their own focused searching • only a small proportion (about 1%) of the medical literature is clinically relevant

4. The Ingredients of EBM • Focused questions • Hierarchy of evidence • Filters • Problem based learning • Scenarios • Anatomy of the question • Shared expertise (SEE-ONE, DO-ONE, TEACH-ONE)

5. Focusing the question • Helping requester to break information need down into EBM anatomy clarifies the originating question. • “OR” within categories and “AND” between categories.

6. Understanding study design • Adds to your ability to recognise “good studies”and “bad studies”. • Helps you to identify the question being answered by an article.

7. Using methodological filters • One line, sensitive and specific versions • rely on publication types or occurrence of textwords to identify methodologically superior studies • are also used to compile pre-filtered database products e.g.. Cochrane Library (clinical trials), DARE (reviews) & NHS EED (economic evaluations)

8. Types of question - primary studies Diagnosis Etiology Prognosis Therapy Types of article - secondary studies Reviews Economic Evaluations Guidelines [and now Qualitative] Topics

9. The Process • Clinical Scenario • Focusing the question • Translating into MeSH terms • Conducting the literature search • Applying the methodological filters • Filtering for quality studies • Specialist resources

10. For each study: User Guides from JAMA ACP Journal Club or EBM MEDLINE Guides CASP filters page http://www.phru.org.uk/~casp/filters.htm About ADEPT: Becoming ADEPT: Project Overview - HLR Dec 1997. Becoming ADEPT: delivering distance learning on EBM to Librarians - HLR Sept 1998. Resources

11. Principles of Study Design: a librarian’s perspective Andrew Booth

12. Scenario You are a postgraduate medical librarian in Kleptovale NHS Trust. You have bid for a Nicksnix Library security system. The postgraduate Dean wants some evidence that it is effective. There is no published evidence so you will need to conduct an original study. What are you going to do?

13. Lower forms of evidence • Anecdote (I once knew a librarian who……) • Case study • Case series

14. Answer. A Case-control study • You call up the Regional Library Unit. Details of 10 libraries with book losses of >5% (cases) and of 10 libraries with losses of <1% (controls). • Phone all 20 libraries and ask “Do you use a library security system?” Yes/No

15. You compile a 2 by 2 table.

16. But........ • Controls might be underreporting their losses to make system look good. • People with security systems may be more security conscious (using other methods) • Bias (flaw in research method) or confounding (some other factor not taken into account).

17. Advantages Quick and cheap It’s the only method for rare events Requires fewer subjects than other designs Disadvantages Relies on recall/records Open to confounding Selection of controls is difficult Potential bias in recall or selection. Case-control studies [Retrospective]

18. Answer: A Cohort Study Convince 110 members of HLG to take part in a prospective cohort study. Over a two year period you record who uses the system [Exposed] and who doesn’t [Non-Exposed]. At end of two years you calculate rate of heavy losses within both groups.

19. Another 2 by 2 table

20. But..... • OK so you may have eliminated recall and reporting bias through baseline data collection, but • Libraries with security systems may be in richer areas and less prone to theft anyway.

21. Advantages Subjects can be matched Eligibility criteria can be standardised Easier to run than an RCT. Disadvantages Blinding is difficult Randomisation is not present Requires a large sample and longer follow up. Cohort studies

22. Answer: An RCT • You go for a sponsored Randomised Controlled Trial. You recruit another group of HLG members. You randomly assign half with a free NicksNix system and the others must go without. After a year you have the following results.

23. Yet another 2 by 2 table

24. Finally.... After three years and thirty minutes and three separate studies the Postgraduate Dean believes he has the right answer:- No difference, No Nicksnix, No comment!!!

25. Advantages Unbiased distribution of confounders Blinding more possible Randomisation facilitates statistical analysis Disadvantages Expensive in time and money Volunteer bias Ethical problems, sometimes May create artificial behaviour Randomised Controlled Trials

26. Postscript Practically, you wouldn’t go to all that effort. Maybe use a cross-over design where one Library (n-of-1 study) or more went through periods without and then with a system. You would need to make sure that there was a washout period. Also you would have to guard against a placebo effect.

27. Hierarchy of effectiveness • Systematic Review • Randomised Controlled Trial • Cohort study [Prospective] • Case-control [Retrospective] (May be contemporary or historical) • Case series • Individual case study

28. There are other hierarchies E.g. Hierarchy of patient experience • Qualitative research study • Interviews/Surveys • Case study • Anecdote • C.p. Signal to noise ratio (Edwards AG, Russell LT & Stott NCH (1998) Signal versus noise in the evidence base for medicine: an alternative to hierarchies of evidence? Family Practice 15 (4): 319-322)

29. Constructing a QuestionMarishona Ortega

30. EBP Process • Define problem • Find evidence • Appraise evidence • Apply results of appraisal • Evaluate change • Redefine problem

31. Formulating a question using PICO • Population/Patient/Condition • Who is the question about? • Intervention/Exposure • What is being done to or happening to the patient/population? • Comparison(s) • What could be done instead of the intervention? • Outcome(s) • How does the intervention affect the patient/population?

32. Another way of looking at PICO

33. Focused Questions - the benefits • Guides search process • Prompts for considering synonyms and alternatives • Saves time - increases relevance

34. Translating your question into a strategy Your department is exploring the idea of introducing near-patient testing for Group A ß-Streptococcal throat infection. You have been asked by your manager to gather the evidence for this procedure with particular reference to sensitivity, specificity and cost.

35. PICO Applied: • Patient/Condition • Group A ß -Streptococcal throat infection • Intervention • Near-patient testing or rapid test • Comparison • Laboratory testing • Outcome • Sensitivity, specificity, cost

36. Now your turn… As background to your service you are compiling information identifying the risks of infection from HIV, Hepatitis B & C and CMV following homologous blood transfusion. How would you structure your search?

37. Now your turn - contd • Patient/Population • Persons receiving blood transfusion • Intervention • Homologous blood transfusion • Comparison • Another form of blood transfusion i.e. autologous • Outcome • Not becoming infected with HIV, Hepatitis B&C or CMV

38. EBP Process • Define problem • Find evidence • Appraise evidence • Apply results of appraisal • Evaluate change • Redefine problem

39. Where do I start? • Develop your question • Decide on the most appropriate source(s) • Divide your search into ‘concepts’ • Think of alternative terms for each concept • Search each concept separately • Combine conceptsusing Boolean logic

40. Therapy Studies:Design, Terminology and Filters

41. Learning Objectives • Describe the main characteristics of a rigorous therapy study. • Recognise some of the terminology associated with studies of therapy • Itemise sub-headings associated with treatment • Avoid common pitfalls associate with searching for therapy studies • Utilise the methodological filters associated with therapy literature searches

42. What is a therapy study? • Treatment or management of a condition • Objective of treatment • Choice of treatment • Target of treatment • Literature-based evidence can assist with all three aspects, but most particularly “Choice of treatment”

43. Therapy Studies • A search for therapy studies focuses on the decision between treatment choices • Therefore the evidence will be comparative • The preferred design for a therapy study is a RANDOMISED CONTROLLED TRIAL (RCT)

44. Searching for therapy studies

45. 1 randomized controlled trial.pt. 2 controlled clinical trial.pt. 3 randomized controlled trials/ 4 random allocation/ 5 double blind method/ 6 single blind method/ 7 or/1-6 8 clinical trial.pt. 9 exp clinical trials/ 10 (clin$ adj25 trial$).ti,ab. 11 ((singl$ or doubl$ or trebl$ or tripl$) adj25 (blind$ or mask$)).ti,ab. 12 placebos/ 13 placebos.ti,ab. 14 random.ti,ab. 15 research design/ 16 or/8-15 17 comparative study/ 18 exp evaluation studies/ 19 follow up studies/ 20 prospective studies/ 21 (control$ or prospectiv$ or volunteer$).ti,ab. 22 or/17-21 23 7 or 16 or 22 24 animal/ 25 human/ 26 24 and 25 27 24 not 26 28 23 not 27 Methodological filters 1

46. Methodological filters 2 Reinhard Wentz: 1 explode clinical trials 2 explode research design 3 randomized controlled trial.pt. 4 clinical trial.pt. 5 (single or double or treble or triple).tw. 6 (mask$ or blind$).tw. 7 5 and 6 8 placebos/ or placebo$.tw. 9 1 or 2 or 3 or 4 or 7 or 8

47. Methodological filters 3 Mid-range strategy from Health Information Research Unit, McMaster: 1 randomized controlled trial.pt. 2 or dt.fs. 3 or tu.fs. 4 or random$.tw. 5 or/1-4

48. And last but not least... The one-line filter: clinical trial.pt • Retrieves 97% of rigorous therapy studies • Only includes 3% of irrelevant studies

49. So how does this work in practice? A 17-year-old female was travelling home one night when the car her friend was driving careered off the road. Fortunately, no-one was seriously injured but she presented to A&E with localised low back pain and was diagnosed with lumbar strain. For some time the Senior Physio has been considering the treatment for low back pain and wonders if acupuncture might be a more effective and comfortable alternative. She asks you to run a search to find the relevant evidence.

50. What’s your Question? • Patient/Condition • 17 year old female with low back pain/lumbar strain • Intervention • Acupuncture • Comparison • Existing treatment • Outcome • Pain relief