Research Guides: Nursing: Levels of Evidence

EBM Pyramid

Evidence-Based Medicine is the integration of best research evidence with clinical expertise and patient values. (Sackett DL, Straus SE, Richardson WS, et al. Evidence-based medicine: how to practice and teach EBM. 2nd ed. Edinburgh: Churchill Livingstone, 2000.)

Filtered Evidence

Filtered resources appraise the quality of studies and often make recommendations for practice.

Systematic Reviews / Meta-Analyses

Authors of a systematic review ask a specific clinical question, perform a comprehensive literature search, eliminate the poorly done studies and attempt to make practice recommendations based on the well-done studies. A meta-analysis is a systematic review that combines all the results of all the studies into a single statistical analysis of results.

Cochrane Library Cochrane reviews represent the highest level of evidence on which to base clinical treatment decisions. Cochrane Systematic Reviews consist of detailed, structured topic reviews of hundreds of articles. Teams of experts complete comprehensive literature reviews, evaluate the literature, and present summaries of the findings of the best studies.
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Free summaries are available at the Cochrane site and PubMed Health.
CRD Full-text database containing structured abstracts of systematic reviews from a variety of medical journals. CRD is produced by the National Health Services' Centre for Reviews and Dissemination (NHS CRD) at the University of York. CRD records cover topics such as diagnosis, prevention, rehabilitation, screening, and treatment. Free via the CRD site and PubMed Health.
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The Database of Abstracts of Reviews of Effect (DARE)

PubMed This link opens in a new window
CONTENT: Free database from the National Library of Medicine containing biomedical literature in the fields of medicine, nursing, dentistry, veterinary medicine, on the health care system, and preclinical sciences. Searches include the resources from PreMedline and Medline.

RESOURCE TYPES: Journals, online books, additional relevant web sites, and links to the other NCBI molecular biology resources.

COVERAGE: Database of more than 21 million citations covering biomedical literature. Citations may include links to full-text content from PubMed Central and publisher web sites and includes MedLine content. Developed and maintained by the National Center for Biotechnology Information (NCBI) at the U.S. National Library of Medicine (NLM) located at the National Institutes of Health (NIH).

Critically-Appraised Topics

Authors of critically-appraised topics evaluate and synthesize multiple research studies.

National Guideline Clearinghouse - AHRQ A comprehensive database of evidence-based clinical practice guidelines and related documents produced by the Agency for Health Care Research and Quality, in partnership with the American Medical Association and the American Association of Health Plans. Updated weekly. Note: Guideline evidence varies from expert opinion to high levels of evidence.
ICSI, Institute for Clinical Systems Improvement: Guidelines & More
Recommendations for Primary Care Practice: U.S. Preventive Services Task Force.
MedScape

Critically-Appraised Individual Articles

Authors of critically-appraised individual articles evaluate and synthisize individual research studies.

Evidence Updates from BMJ Quality articles from over 110 clinical journals are selected by research staff, and then rated for clinical relevance and interest by an international group of physicians. Includes a searchable database of the best evidence from the medical literature and an email alerting system. From BMJ Publishing Group and McMaster University's Health Information Research Unit. Free (requires registration)
Bandolier Bandolier is an independent journal about evidence-based healthcare published in the UK. It includes “information about evidence of effectiveness (or lack of it), and put[s] the results forward as simple bullet points of those things that worked and those that did not: a bandolier with bullets. Information comes from systematic reviews, meta-analyses, randomised trials, and from high quality observational studies.”

Filtered and Unfiltered

ClinicalKey This link opens in a new window
Point-of-need
Content: A clinical search engine providing fast, concise answers to support clinical decisions.

Resource type: Books, Journals, Drug Monographs (Gold Standard), Multimedia, Guidelines and Patient Education.

Coverage: Current publications of titles covered, updated at least once a month.

Trip Database TRIP (Turning Research Into Practice) Database Plus, search engine, evidence and search across other content types including images, videos, patient information leaflets, educational courses and news.
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Simultaneously searches evidence-based sources of systematic reviews, practice guidelines, and critically-appraised topics and articles -- including most of those listed above and many more. Also searches MEDLINE’s Clinical Queries, medical image databases, e-textbooks, and patient information leaflets.

Unfiltered Evidence

Evidence is not always available via filtered resources.

Searching the primary literature may be required.

PubMed This link opens in a new window
CONTENT: Free database from the National Library of Medicine containing biomedical literature in the fields of medicine, nursing, dentistry, veterinary medicine, on the health care system, and preclinical sciences. Searches include the resources from PreMedline and Medline.

RESOURCE TYPES: Journals, online books, additional relevant web sites, and links to the other NCBI molecular biology resources.

COVERAGE: Database of more than 21 million citations covering biomedical literature. Citations may include links to full-text content from PubMed Central and publisher web sites and includes MedLine content. Developed and maintained by the National Center for Biotechnology Information (NCBI) at the U.S. National Library of Medicine (NLM) located at the National Institutes of Health (NIH).

ClinicalTrials.gov

It is possible to use specific search strategies to achieve the highest possible level of evidence.

In PubMed: Click on "Clinical Queries" on the home page; Select "Find Systematic Reviews" and enter your search query.

CINAHL with Full Text This link opens in a new window
CONTENT: Nursing, allied health disciplines, cardiopulmonary technology, emergency services, health education, med/lab technology, medical assistance, medical records, occupational therapy, physical therapy, radiologic technology, respiratory therapy, surgical technology, and physician's assistant.

RESOURCE TYPES: Journal articles, medical text books, nursing dissertations, educational software, legal cases, clinical innovations, critical paths, drug records, research instruments and clinical trials. In addition, this database offers access to health care books, selected conference proceedings, standards of practice, audiovisuals and book chapters.

COVERAGE: Indexes more than 3,000 journals in the field of nursing and allied health, dating back to 1981.

Background Information/Expert Opinion

Note: Evidence in these resources may vary from expert opinion to high levels of evidence.

Harrison's Online This link opens in a new window
CONTENT: The following parts of the text are: Cardinal Manifestations and Presentation of Diseases, Introduction to Clinical Medicine, Genes, the Environment, and Disease, Regenerative Medicine, Aging, Nutrition, Oncology and Hematology, Infectious Diseases, Terrorism and Clinical Medicine, Disorders of the Cardiovascular System, Disorders of the Respiratory System, Critical Care Medicine, Disorders of the Kidney and Urinary Tract, Disorders of the Gastrointestinal System, Disorders of the Joints and Adjacent Tissues, Endocrinology and Metabolism, Neurologic Disorders, Poisoning, Drug Overdose, and Envenomation, High-Altitude and Decompression Sickness and several Clinical Procedure Tutorials.

RESOURCE TYPES: Internal medicine eBook.

COVERAGE: Entire book full text, most recent edition.
AccessMedicine This link opens in a new window
CONTENT:

Health science/medical textbooks in all major medical specialties. Some of the titles included are Harrison’s Principles of Internal Medicine, CURRENT Medical Diagnosis & Treatment, Tintinalli’s Emergency Medicine, and LANGE Basic Science and Clinical Libraries. Drug Information that users can search by the drug’s generic name, trade name, or class is also part of this database.

RESOURCE TYPES:

Full text medical reference textbooks, with images; a differential diagnosis tool called ‘Diagnosaurus’ which allows users to browse more than 1,000 differential diagnoses; QMDT (Quick Medical Diagnosis & Treatment), an outline of the most common medical conditions with a quick, concise answer; Diagnostic test section from Pocket Guide to Diagnostic Tests; Video/Audio on bedside and office-based procedures, diagnostic tests, treatments and conditions; Case Files; Self-Assessment Tools such as practice tests and flashcards; and Patient Education Handouts.

COVERAGE:

Most recent editions of more than 85 medical reference textbooks.