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Advanced PubMed EBP: Searching Clinical Questions Jessica Cole, MLIS, AHIP PHA 520 November 19, 2013

Evidence-Based Practice: Finding evidence

Advanced PubMedEBP: Searching Clinical Questions Jessica Cole, MLIS, AHIPPHA 520November 19, 2013Evidence-Based Practice

Evidence based medicine is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based medicine means integrating individual clinical expertise with the best available external evidence from systematic research.EBP Research StepsASK-Convert information need into a question. ACQUIRE-Find best evidence to answer question.APPRAISE-Critically appraise evidence.INTEGRATE evidence with clinical expertise & patient values to apply in practice.EVALUATE performance.

Database Searching SkillsWe will focus mostly on the first two steps, but I will give you resources at the end to help you with appraisal3Dont Expect Research to be a Linear Process!

Define Research QuestionConvert the information need into a specific question. This will guide your research process.Convert question to PICO format to help you break it down and plan a database search strategy.Determine best concepts/terms to represent each PICO element. These are the terms you will string together to build your database search.1. ASKPICO QuestionInclude the following PICO elements in your question

P Patient characteristics/conditionI Intervention (or diagnosis/prognosis)C Comparison intervention (if applicable)O Outcome of interest

In the elderly, does Tai Chi reduce accidental falls?

1. ASKQuestionSearch StrategyTransition from Step 1. Asking the Question to Step 2. Acquiring evidence:

Planning the database search strategy

1. ASKPlanning the SearchIn the elderly, does Tai Chi reduce the number of accidental falls?


ElderlySlip & Fall?Tai ChiReduceBig Picture Example 1: Fast Forward to StrategyThis is what our search strategy will look like in the end. What follows in the next slides are the steps taken to build this search:

In the elderly (P), does Tai Chi (I) reduce the number of accidental falls? (O)2. ACQUIRE


Big Picture Example 2: Fast Forward to StrategyThis is another example of a search built for the question below. For the last question, P+I+O were searched. For this question and approach, we search P+I+C.

In an adult diagnosed with depression(P), is St. John's Wort (C) as effective as SSRIs (I) at reducing depressive symptoms?

2. ACQUIREPICPlanning the SearchList the main terms/concepts from your PICO question.Which terms are most important for the search?Always search for the P and I elements with the best terms to capture a concept. C is optional, depending on whether your question is comparing two interventions. For certain questions, the outcome O will be an important term to search, and for others it will not.Example of when NOT to search for outcome: If the P is a condition characterized by having pain and your question is how to reduce that pain, PAIN, is already implied.

2. ACQUIREPlanning the SearchKeywords vs. MeSH (Medical Subject Headings)

Strengthen a search by using terminology the database understands!2. ACQUIREWhy Controlled Vocabulary? (MeSH)

Cola, Pop, Soda, Coke, Soda Pop? Bill, Money, Dollar, Cash, Currency?2. ACQUIREPlanning: MeSH DatabaseSearch your keywords in the MeSH database for other terms more likely to be recognized by the database. Write down the MeSH for later.


Find Best Search Terms2. ACQUIREA search for fall in the MeSH Database displays the appropriate MeSH term, Accidental Falls.Find Best Search TermsWhen to search with ORWhen a term you believe is common has a different MeSH heading.(Tai Chi OR Tai Ji) will retrieve results that use EITHER term. Tai Chi is our keyword. Tai Ji is the MeSH term.

2. ACQUIRE(P) Elderly

(I) Tai Chi

(C) No comparison-

(O) Reduce FallsAged (or use age filters) and

(Tai Chi OR Tai Ji)and

Accidental FallsOur Original Keywords from Clinical QuestionDecision: Terms to Search after finding MeSH Terms (with AND)

Find Best Search Terms2. ACQUIRERemember Filters!Many times the P of PICO question has filters to apply at the end of the search so you dont need to search for terms like female or adolescent.Examples: Age groups, gender

2. ACQUIREConduct the Search


Conduct the Search2. ACQUIREIAge filters can be applied after the search, or you can search the term AgedPC=None in this QO

Apply FiltersFirst see # results and review article titles without applying the filters.View results with filters applied: Be aware that filters might also remove some good results. Always try both ways.Use filters for levels of evidence here or at a later point of refining/appraising the search.Filter must show checkmark.Remember to clear filters!

2. ACQUIREFilters: Levels of EvidenceFilters for types of evidence can also be applied now.

2. ACQUIREFilters: Article TypesSystematic Reviews/Meta-Analysis are strongest level of evidence for most questions because they synthesize several studies. Also see Clinical Practice Guidelines.For individual studies, best design/article type is:

2. ACQUIREReview ResultsAppraiseTransition from Step 2. Acquiring the evidence to Step 3. Critically appraise the evidence Overlap.SAVE good results as you go! Even if you are not yet critically appraising individual articles while scanning results, hold onto those that look promising.2. ACQUIRE

Save Good Articles2. ACQUIRE

Critical AppraisalAre the results valid?Did intervention and control groups start with the same prognosis? Were patients randomized?Was group allocation concealed?Were patients in the study groups similar with respect to known prognostic variables? Was prognostic balance maintained as the study progressed? To what extent was the study blinded?Were the groups prognostically balanced at the study's completion? Was follow-up complete?Were patients analyzed in the groups to which they were first allocated?Was the trial stopped early?

Users' Guide to Medical Literature: A Manual for Evidence-Based Clinical Practice, 2nd Edition.

3. APPRAISECritical AppraisalWhat are the results?How large was the treatment effect?What was the relative risk reduction?What was the absolute risk redHow precise was the estimate of the treatment effect? What were the confidence intervals?Users' Guide to Medical Literature: A Manual for Evidence-Based Clinical Practice, 2nd Edition.

3. APPRAISECritical AppraisalHow can I apply the results to patient care? Were the study patients similar to my population of interest?Does your population match the study inclusion criteria?If not, are there compelling reasons why the results should not apply to your population?Were all clinically important outcomes considered?What were the primary and secondary endpoints studied?Were surrogate endpoints used?Are likely treatment benefits worth the potential harm and costs?What is the number needed to treat (NNT) to prevent 1 adverse outcome or produce 1 positive outcome?Is the reduction of clinical endpoints worth the increase of cost and risk of harm?Users' Guide to Medical Literature: A Manual for Evidence-Based Clinical Practice, 2nd Edition.

3. APPRAISECritical AppraisalCritical appraisal information at JAMA Evidence

3. APPRAISESummary

1. ASK

2. ACQUIRE3. APPRAISEFirst, know what you are looking for! Write a focused clinical question based on PICO format to help you plan your search strategy translate your question into the best search terms.Conduct an Advanced PubMed search with the best terms identified from PICO, using Boolean operators and applicable filters to limit results. Save good results as you go and experiment for different sets of results. Always search P & I concepts at minimum.Critically appraise individual articles/studies. Upon closer examination, is it still relevant to your PICO question? Are results valid, and have you carefully looked for the best highest levels of evidence available on this topic?PICO Search Demo VideoIn a 30-year-old male patient diagnosed with depression, is St. John's Wort as effective as SSRIs at reducing depressive symptoms?

P: Depressive disorder [MeSH searched as keyword] ANDI: Serotonin uptake inhibitors [MeSH searched as keyword] ANDC: (Hypericum [MeSH searched as keyword] OR St. John's Wort)O: Desired outcome is efficacy, but this term is not part of the search strategy because it is already implied in the search.

Use PubMed Advanced search builder to string these terms together with AND (Enter the OR terms in the same line - which is the third line in this demo, and leave the Boolean operator on the left of the search builder as AND) Click search.Step 3: Apply filters: English, Humans, Systematic Review [subset]

See https://www.youtube.com/watch?v=_pVxRw-y8-M

Tip: How to CheatFind 1 relevant article and take a closer look for clues. Examine MeSH terms for ideas for terms to search.Also view Related Citations.

PubMed Search TipsNOT ENOUGH RESULTS?Search synonyms with OR (i.e. aqua therapy OR aquatic exercises)Find one good article and view Related Citations & MeSHRemove filters. Reduce number of ANDs in search strategy (Search P AND I)

TOO MANY RESULTS? Add more search terms with AND. Use filters/limits to narrow results.

DO:Experiment! (Keywords, Boolean operators, filters)Save good references as you go with the Clipboard/email/When searching with an OR, place the two terms on same line in search builder so search functions properly.Contact Your Librarian for Help! [email protected]