Mount Marty University Nursing Program: Library Hub

To receive/check clinically significant and reliable evidence updates in your chosen specialty/ies, register in: 

• AANA Puts Evidence to Practice

• Accessss Smart Search 

• Access Pharmacy-Topics in Evidence-based Pharmacy Practice

• CDC-Email Alert (Get Email Updates)

• DynaMed (look under 'Recent Alerts' by scrolling down on the main page)

• Evidence-Based Care Sheets in 'CINAHL'

• EBM Focus by DynaMed

• Evidence-based Practice Center (EPC) Reports

• NEJM

David Sackett defined Evidence-Based Medicine (EBM) as “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient”.  Put in other words, EBM is the integration of three elements at the same time, these are Clinical Expertise, Best Research Evidence, and the Patient's Values as shown in the below diagram.  It acknowledges that unsystematic clinical experience and pathological rationale are insufficient grounds for sound clinical decision-making.

Medicine was first to adopt the principles of EBM, then other healthcare disciplines have followed ex. nursing, mental health, dentistry, cardiology, orthopedics, etc… leading to Evidence-Based Health Care (EBHC).

There are five steps for applying EBM Principles:

1. Construct a well-built clinical question and classify it into one category (therapy, diagnosis, etiology, or prognosis).

2.  Find evidence in health care literature.

3.  Critically appraise for validity and usefulness.

4.  Integrate evidence with patient factors.

5.  Evaluate the whole process.

JAMA publishes  "Users' guides to the medical literature" series useful for learning about evidence-based practice.  Similarly, BMJ publishes “How to read a paper” series. 

The Evidence-Based Practice process starts with a clinical scenario that needs the best answer. First, break down the clinical case into PICO analysis:

Then ask a well-built structured clinical question that should be directly relevant to the problem at hand and should be phrased to facilitate searching for a precise answer.

Then determine the category of the clinical question, there are four main ones:

• Therapy:  solves questions about which treatment to administer, and what might be the outcome of different treatment options.  For most therapy questions one may want to look for the best evidence namely a randomized controlled study, and if the study is double-blind, that would be better.

• Diagnosis: solves questions about the degree to which a test is reliable and clinically useful, after comparing the result of a diagnostic test with that of a standard test regarded as a "gold standard".

• Etiology:  solves problems about the relationship between a disease and a possible cause.  Example: find out if a diet rich in saturated fats increases the risk of heart disease, and if so by how much.

• Prognosis: answers questions about a patient's future health, life span and quality of life in the event one chooses a particular treatment option. Example: find how would the quality of life change for a patient who undergoes surgery for prostate cancer. 

The next step is to determine the best study design needed to answer that particular clinical question.

Levels of evidence: the strength of evidence depends on the type of research method used:

• Strong evidence from at least 1 systematic review of multiple well-designed RCT.

• Strong evidence from at least 1 properly designed RCT of appropriate size.

• Evidence from well-designed trials without randomization, or case-controlled studies.

• Evidence from well-designed non-experimental studies from more than 1 center or research group.

• Opinions of respected authorities, based on clinical evidence, descriptive studies, or reports of expert committees.
  

After retrieving the research literature, evaluate/critically appraise the evidence for its validity and adherence to truth.  This requires knowledge of basic statistics and a familiarity with the terminology of EBM ex. positive predictive value, likelihood ratio, number needed to treat NNT, etc...This evaluation depends on the category type of clinical question at hand according to the following criteria:

Therapy: When evaluating a therapy question ask yourself:

• Was the study randomized and double-blind to prevent bias?

• Was follow-up > 80%

• Were the groups similar at the start of the trial?

• Were all enrolled patients included in the conclusion of the study?

• Was the study valid?  did the authors answer the question?

• Do the results present an unbiased estimate of the treatment effect?

• How large is the treatment effect?

• Will the results help my patient?

• Were the study patients like your patient?

• Are the benefits worth the harm and cost?

Diagnosis: Diagnostic tests are evaluated in a manner to ascertain which are more accurate, faster, less expensive, and less invasive than existing diagnostic tests. Good diagnostic tests must provide positive results when the disease is present, and negative results when the patient does not have the disease.  In contrast to therapeutic evaluations, all persons involved in a new diagnostic test must receive the test. The results are compared with the results of the "gold standard" test. To evaluate a diagnosis question ask yourself:

• Did the authors do a blind comparison with a gold standard?

• Did patients in the study undergo both the diagnostic test and the gold standard?

• Did the paper describe the method for doing the test?

• Were the patients tested similar to your patient?

• Are the results of the test useful?

• Did the patient sample include an appropriate spectrum of patients like those found in general practice?

Etiology: To evaluate an etiology question ask yourself:

• Were the exposures and outcomes measured similarly in both groups (exposed and non-exposed patients)?

• Was the comparison group similar to the outcome group in all aspects except for the variable in question?

• Was follow-up sufficiently long and complete?

Prognosis: uses cohort studies to see how the disease is progressing. To evaluate a prognosis question ask yourself:

• Was the patient sample selected to reflect a well-defined point in the course of the disease?

• Was the follow-up adequate and complete (>80%)?

• Were there objective and unbiased outcome criteria used?

For more information check CASP Appraisal Checklists or Critically Appraising articles by category by Duke University.

Additionally rom JAMA evidence:

An Approach to Evidence-Based Medicine

Appraising Evidence About Diagnostic Tests

Appraising Evidence About Harm

Appraising Evidence About Prognosis

Appraising Evidence About Therapy

Appraising Evidence From a Systematic Review and Meta-analysis

Appraising Qualitative Research

Also, check a suggested Guidelines for Critical Appraisal of Papers Anesthesiology Journal Club Queen's University © Joel Parlow, revised 2010.

Randomized Controlled Trials (RCT): (answers therapy, prevention questions)
Randomization avoids selection bias. Here we have two groups, a treatment, and a control group. The treatment group receives the treatment under investigation and the control group receives a placebo, and both groups are followed up.

Cohort Study:  (answers prognosis, etiology, prevention questions)
Defined populations are followed in an attempt to determine distinguishing subgroup characteristics.   Researchers identify and compare two groups over a period of time; one of the groups has a particular condition or receives a particular treatment, and the other does not.  At the end of the specified time, researchers compare the two groups to see how they did. 

Case-Control Study: (answers prognosis, etiology, prevention questions)
Studies identify patients who already have the outcome of interest and control patients without that outcome and look back to see if they had exposure of interest or not. 

Case Series / Case Reports:  (answers prognosis, etiology, prevention questions)
Consist either of collections of reports on the treatment of individual patients or of reports on a single patient.

How to Apply the results of a study to individual patients: Once you determine that the study methodology is valid, examine results if applicable to your patient, using your clinical expertise. For each category, the following different questions have to be answered.

Therapy:

• Is my patient so different from those in the study group that the results cannot be applied?

• According to the study results, how much could my patient benefit from the treatment?

• Are the treatment and its consequences consistent with my patient's values and beliefs?

Diagnosis:

• Is the test affordable, accurate, and available locally?

• Can estimate the pretest probability of the disease in question?

• Will the posttest probability affect my management?

Etiology:

• Can the study results be extrapolated to my patient?

• What is my patient's risk for adverse effects?

• Can my patient's preferences & expectations be met by an alternative therapy?

Prognosis:    

• Is my patient similar to the patients in the study group?

• Will the evidence alter my choice of treatment?

EBM Calculators

• Duke University explanation of EBM Calculations

• EBM Toolbox

Wegner subscribes to a large list of Evidence-Based Practice resources that are represented in the below EBM Pyramid.

Evidence Pyramid

The highest level of evidence is for Meta-analysis, then Systematic Reviews, then Randomized Controlled Trials, etc...The base has the largest number of literature studies and provides the least strength of evidence. 

I.   TRIP (Turning Research Into Practice) Database Plus

I. TRIP (Turning Research Into Practice) Database

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. Results are filtered by MEDLINE's Clinical Queries, guidelines, systematic reviews, evidence-based synopses, medical image databases, e-textbooks, and patient information leaflets.

II.   Filtered Resources: these appraise the quality of studies and often make recommendations for practice.

A. Systematic Reviews / Meta-Analysis

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

Systematic Reviews in Cochrane

Consists 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.

Systematic Reviews are also searchable in PubMed & CINAHL

• PubMed: Click on “Clinical Queries" on PubMed main screen; select  'Find Systematic Reviews' after entering a search query.

• CINAHL: To limit your CINAHL search to the best evidence-producing studies: Do the search as usual then click "More Limits" and select options under 'Publication Type'.

             OR

      Initially select from under 'Search Options', the publication type to be 'Systematic Reviews'.

B. Critically-Appraised Topics: authors of critically-appraised topics evaluate and synthesize multiple research studies.

Agency for Healthcare Research and Quality (AHRQ)

A comprehensive database of evidence-based clinical practice guidelines and related documents was produced by the Agency for Health Care Research and Quality, in partnership with the American Medical Association and the American Association of Health Plans. This guideline evidence varies from expert opinion to high levels of evidence.

C. Critically-Appraised Individual Articles: authors of critically-appraised individual articles evaluate and synopsize individual research studies.

DynaMed

DynaMed is a clinical reference tool created by physicians for physicians and other health care professionals for use primarily at the 'point-of-care'. With clinically-organized summaries for nearly 2,000 topics, DynaMed is an evidence-based reference that helps answer clinical questions. It is updated daily and monitors the content of over 500 medical journals and systematic evidence review databases directly and indirectly by using many journal review services. Each publication is reviewed and evaluated for clinical relevance and scientific validity.

e-Journals

Primary research articles within the discipline of family practice, internal medicine, pediatrics, obstetrics, gynecology, psychiatry, and surgery are selected for quality and clinical relevance. A structured abstract and expert commentary are provided for each study.

• JBI reports (Online)

• Evidence-Based Nursing

• International Journal of Evidence-Based Healthcare

III.   Unfiltered Resources

Evidence is not always available via filtered resources. Searching the primary literature may be required, but use specific search strategies in PubMed/CINAHL to achieve the highest possible level of evidence.

A. PubMed

To limit your PubMed search to the best evidence-producing studies: Click on "clinical queries" (from PubMed main page). This specialized search is intended for clinicians and has built-in search "filters." Four study categories--therapy, diagnosis, etiology, prognosis--are provided, and you may indicate whether you wish your search to be more sensitive (i.e., include most relevant articles but probably include some less relevant ones) or more specific (i.e., including most relevant articles but probably omit a few).

B. CINAHL: Cumulative Index to Nursing and Allied Health Literature

To limit your CINAHL search to the best evidence-producing studies: Do the search as usual then click "More Limits" and select options under "Clinical Queries".

C. Evidence Based Medicine (nih.gov)

D. PICO- PubMed for Handhelds (nih.gov) 

IV.   Background Information/Expert Opinion: evidence in the below resources may vary from expert opinion to high levels of evidence.

DynaMed

DynaMed is a clinical reference tool created by physicians for physicians and other health care professionals for use primarily at the 'point-of-care'. With clinically-organized summaries for nearly 2,000 topics, DynaMed is an evidence-based reference that helps answer clinical questions. It is updated daily and monitors the content of over 500 medical journals and systematic evidence review databases directly and indirectly by using many journal review services. Each publication is reviewed and evaluated for clinical relevance and scientific validity.

eBooks

Wegner offers a large collection of full-text electronic textbooks.