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Evidence Based Medicine: Acquiring Evidence

Home Formulating Questions → Acquiring Evidence → Appraising Evidence Tools & References Teaching EBM

 

Levels of clinical evidence

The medical literature represents the broadest spectrum of study, and not all of them are appropriate for answering clinical questions. Each study type can be organized into various levels or quality of evidence. In evidence based medicine, the highest possible levels of evidence is desired. Knowing these levels of evidence, can help in filtering the literature to only the highest evidence available for a specific clinical question.

EBMpyramid(Sackett DL, Straus SE, Richardson WS, et al. Evidence-based medicine: how to practice and teach EBM. 2nd ed. Edinburgh: Churchill Livingstone, 2000.)

Developing a search strategy for primary literature

When searching primary literature, you will need to translate the structured clinical PICO question, into a search strategy that can be entered into a database in order to retrieve relevant literature.

1) Translate major concepts into search terms

Identify the major concepts of your question and translate natural language to keywords, subject descriptors, MeSH terms or other controlled vocabulary terms.

Start with the P and the I only to begin your search and keep initial search results broad.

Natural Language Database controlled vocabulary or keyword
P (Problem/Patient/Population)
=hospital acquired infection
cross infection [MeSH]cross infection [CINAHL]
I (intervention/indicator)=hand washing hand disinfection [MeSH] handwashing [CINAHL]

Combine the terms with boolean operators: cross infection AND  (Handwashing OR Hand disinfection)

2) Narrow your search with filters

After viewing the initial search results you may decide to narrow your search with terms for the Comparison, Outcome, Time factors or Type of study. Or you may view results, abstracts, and full text of articles to view the comparison and outcome elements.

View examples of clinical questions translated to database searches
See a listing of clinical filters for searching Medline/PubMed

Watch a tutorial on searching PubMed for a PICO question using MeSH controlled vocabulary.

Suggested databases from UAMS Library

These databases are suggested for searching the literature for EBM. UAMS affiliates may need to log in with their credentials to gain access to all full-text articles and products subscribed to by the library on your behalf. Individuals who are not affiliated with UAMS may contact their institutional library or Arkansas Regional Center Library to inquire about access to specific materials or products.

Search primary literature

 

  • PubMed* – Over 20 million citations to scientific research literature. Provided by the National Center for Biotechnology Information (NCBI). Also features Clinical Queries – A PubMed feature with search filters helpful to EBM searches. Filter by Clinical Study Categories, Systematic Reviews, or Medical Genetics.
  • CINAHL Plus with with Full Text (EBSCO) – (for UAMS only) See CINAHL tutorials
    Index of over 4,300 journals from the fields of nursing and allied health, with indexing back to 1937. Searchable cited references for more than 1,300 journals. Full text for over 760 journals, plus legal cases, critical paths, research instruments and clinical trials. Includes Pre-CINAHL.
  • CINAHL Plus with with Full Text (EBSCO) – (for ACH only) See CINAHL tutorials
    Index of over 4,300 journals from the fields of nursing and allied health, with indexing back to 1937. Searchable cited references for more than 1,300 journals. Full text for over 760 journals, plus legal cases, critical paths, research instruments and clinical trials. Includes Pre-CINAHL.
  • PsycINFO (EBSCO) (if the topic contains behvioral or mental health components) – Database of journal articles, book chapters, dissertations & other sources from the American Psychological Association.

Search filtered publications

These are secondary resources which are appraised and reviewed for quality and relevance to evidence based practice.

  • Cochrane Via Ovid – Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Cochrane Methodology Register.
  • EBM Evidence Based Medicine Reviews (Ovid) – 10 concurrent users. Includes Cochrane Database of Systematic Reviews, DARE, ACP Journal Club, and the Cochrane Controlled Clinical Trials Registry.
  • UpToDate On Campus Access (no CME) – Concise topic reviews of published evidence with recommendations for patient care. Includes Lexi-Interact drug interactions analysis tool.
  • UpToDate CME and Off Campus Access – Earn CME/CE/CPD credit every time you research a clinical question using UpToDate. Log in with your UAMS domain account and then register. Use this link on and off campus for CME accrual.
  • TRIP (Turning Research Into Practice) Database – Simultaneously search  for systematic reviews, practice guidelines, cmedical image databases, e-textbooks, etc.

Visit the UAMS Library eResources page for a complete listing of electronic resources and databases available from UAMS Library.