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PUBMED and the EVIDENCE-BASED UNIVERSE Holly Ann Burt Outreach and Exhibits Coordinator NN/LM GMR.

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Presentation on theme: "PUBMED and the EVIDENCE-BASED UNIVERSE Holly Ann Burt Outreach and Exhibits Coordinator NN/LM GMR."— Presentation transcript:

1 PUBMED and the EVIDENCE-BASED UNIVERSE Holly Ann Burt Outreach and Exhibits Coordinator NN/LM GMR

2 OBJECTIVES By the end of this class, attendees will be able to: Define evidence based research, identify process steps and know where the library services fit Recognize types of studies and understand how they related to levels of evidence Formulate literature searches to find such evidence Know where to go for additional information

3 A GENDA Introduction Just What IS Evidence Based? Studies, Studies, Studies Taking it to the Next Level To Literature and Beyond Evidence-Based MeSH MeSH Terms, Subsets, Clinical Queries Critical Appraisal


5 T ERMINOLOGY Evidence-Based Medicine (EBM) Evidence-Based Practice (EBP) Evidence-Based Practice in xxx (EBPx) Evidence-Based Health Care (EBHC) Evidence-Based Nursing (EBN) Evidence-Based Public Health (EBPH) Evidence Based Library and Information Practice (EBLIP) Research Based Evidence (RBE)

6 D EFINITIONS Evidence-based medicine requires the integration of the best research evidence with our clinical expertise and our patient’s unique values and circumstances. Patient Values Clinical Expertise Best research evidence EBM Straus SE, Richardson WS, Glasziou P, Haynes RB. Evidence-based medicine: how to practice and teach EBM 3d ed. London: Churchill Livingstone, 2005

7 D EFINITIONS Evidence-Based Public Health (EBPH): The process of systematically finding, appraising and using contemporaneous clinical and community research findings as the basis for decisions in public health. Jenicek M, Stachenko S. Evidence-based public health, community medicine, preventive care. Med Sci Monit. 2003 Feb;9(2):SR1-7.

8 D EFINITIONS Evidence-Based Practice: A way of providing health care that is guided by a thoughtful integration of the best available scientific knowledge with clinical expertise. This approach allows the practitioner to critically assess research data, clinical guidelines, and other information resources in order to correctly identify the clinical problem, apply the most high-quality intervention, and re-evaluate the outcome for future improvement. NLM MeSH 2009

9 S TEPS IN E VIDENCE B ASED R ESEARCH 1.Asking answerable questions 2.Finding the best evidence 3.Critically appraising the evidence 4.Applying a decision 5.Evaluation Heneghan C, Badenoch D. Evidence-based medicine toolkit. 2d ed. Malden, MA: Blackwell, 2007

10 S TEP 1 Asking answerable questions – focused, searchable, clinical PICO Patient, Problem, Population (subjects) Intervention or therapy – may include coalition-building and/or collaborative programs (study groups) Comparison, Control, Context (study groups) Outcome (results)

11 S TEP 2 Finding the best evidence with which to answer the question through structured searches and understanding the literature Primary Studies Clinical trials Randomized Controlled Trials Multicenter studies Secondary (synthesized, summarized) Studies Reviews Meta-analyses

12 S TEP 3 Critically appraising the evidence for its validity (closeness to the truth), impact (size of the effect) and applicability (usefulness in clinical practice) Is it valid? Is it important? Can it help?

13 S TEP 4 Applying a decision - Combining findings to make a recommendation, placing the evidence into context, incorporating recommendation into a specific patient situation, clinical setting or organization How much will it help a patient or population? Does it meet their values and goals? Is it cost-effective?

14 S TEP 5 Evaluation - Determining and measuring the effectiveness of the practice change over time How could it be done better next time? What is the outcome of using (or not using) particular information and its impact on clinical practice?


16 STUDIES R ESEARCH D ESIGN Case Studies/Reports Community TrialCross Sectional Research Cohort Case-Control Correlational Observational Qualitative Study Interview Experimental Descriptive Randomized Clinical Trial Non-Randomized Clinical Trial Analytical Cambron JA. Study Design. Lombard: National University of Health Sciences; 2008.

17 STUDIES R ESEARCH D ESIGN – D ESCRIPTIVE Investigator studies people and exposures in nature, observational No control or comparison group Studies Correlational – statistical association between variables Case studies – new diseases & treatments, etc. Case report – documenting research’s experience Case series – following a group over time Cross sectional study – survey Community Survey Qualitative study – interview w/open-ended question Migrant studies

18 STUDIES R ESEARCH D ESIGN – O BSERVATIONAL A NALYTIC Investigator collects data without making changes to patient’s life or introducing treatments Control/Comparison group, not randomized Studies Case Control – etiology; examine associations between disease/disorder/health issue and one or more risk factors Cohort Study – measurement of one characteristic, outcome, or issues across two groups Prospective Cohort Retrospective Cohort Time Series Study Cross sectional – to determine prevalence

19 STUDIES R ESEARCH D ESIGN – E XPERIMENTAL Investigator chooses and tests intervention, treatment or exposure Decision as to group allocation can be by either random or non-random methods Control and/or comparison group used Note: Random allocation of subjects to is used to reduce selection bias by investigator and evenly allocate subjects on basis of known and unknown characteristics

20 STUDIES R ESEARCH D ESIGN – E XPERIMENTAL Studies Clinical trials Non-randomized trials (quasi-experiment) Interrupted time series Randomized Controlled Trials (RCT) Double-blind randomized trial Single-blind randomized trial Non-blind trial Crossover trial (may also be observational) Community trials – conducted directly through doctors and clinics Laboratory trials

21 STUDIES R ANDOMIZED C ONTROL T RIAL (RCT) Gold standard – especially for therapy studies Participants are randomly allocated into intervention (treatment) and control (placebo) Phase I – Healthy subjects Phase II – Small group Phase III – Large group prior to marketing Phases IV – Post-marketing study Rigorous evaluation of a single variable Seeks to falsify (rather than confirm) it’s own hypotheses PubMed MeSH: Randomized Controlled Trial [PT]

22 Risk Factors Cause(s) Symptoms Signs, Tests Prognosis Treatment Effect Past Current Future M Y B ROTHER D IED OF S TROKE, W ILL I? Glasziou P. Why bother with evidence-based practice? Oxford: Centre For Evidence- based Medicine; 2010 Frequency Cohort Study Survey Inception Cohort Study Treatments Randomised Trial CT Scan Cross Sectional Study

23 L EVELS OF E VIDENCE Kramer BS. Weighing scientific evidence. Washington DC: National Academies Press; 2009


25 25 Primary : original research Secondary: review articles Tertiary: textbooks, summaries Primary Secondary Tertiary L EVELS OF P EER R EVIEWED I NFORMATION Clark N, IT Applications of EBM Principles. Tallahassee, FL: Florida State University College of Medicine, 2003

26 R EVIEW Review of a body of data that uses explicit methods to locate primary studies and explicit criteria to asses their quality PubMed: Review [PT]

27 S YSTEMATIC R EVIEW Review of a body of data that uses explicit methods to locate primary studies and explicit criteria to asses their quality PubMed: No separate MeSH heading; use the Systematic Review option in Clinical Queries

28 M ETA -A NALYSIS Works consisting of studies using a quantitative method of combining the results of independent studies (usually drawn from the published literature) and synthesizing summaries and conclusions which may be used to evaluate therapeutic effectiveness, plan new studies, etc. A statistical analysis combining or integrating the results of several independent clinical trials considered by the analyst to be “combinable” usually to the level of re-analysing the original data. Pooling, quantitative synthesis. PubMed MeSH: Meta-Analysis [PT]

29 S ECONDARY S OURCES Clark N, 2003

30 L EVELS OF E VIDENCE – 5S Straus S, Haynes RB. Managing evidence-based knowledge: the need for reliable, relevant and readable resources. CMAJ. 2009 April 28; 180(9): 942–945.

31 S YSTEMS, S UMMARIES, S YNOPSES Systems: the ideal. A perfect evidence-based clinical information system would integrate and concisely summarize all relevant and important research evidence about a clinical problem and would automatically link, through an electronic medical record, a specific patient’s circumstances to the relevant information. Summaries/Synopses. Synthesized by experts being extremely reliable and authoritative. Enough and exact information needed to support a clinical action. Removes the patient from the picture and practitioner from the primary literature. Lag between study results, analysis, publication and summary Straus SE, Richardson WS, Glasziou P, Haynes RB. Evidence-based medicine: how to practice and teach EBM 3d ed. London: Churchill Livingstone, 2005

32 Type of Study Meta-Analysis Systematic Review Randomized Controlled Trial Cohort studies Case Control studies Case Series/Case Reports Animal research E VIDENCE P YRAMID Clark N, 2003

33 H OWEVER : The types of studies that give the best evidence are different for the different types of questions In every case, however the best evidence comes from studies where the methods used maximize the chance of eliminating bias Glasziou P, Del Mar C. Evidence-based practice workbook: Bridging the gap between healthcare research and practice. Malden, MA: Blackwell; 2007.

34 Type of QuestionSuggested best type of Study TherapyRCT>cohort > case control > case series DiagnosisProspective, blind comparison to a gold standard Etiology/HarmRCT > cohort > case control > case series PrognosisCohort study > case control > case series PreventionRCT>cohort study > case control > case series Clinical ExamProspective, blind comparison to gold standard CostEconomic analysis Introduction to Evidence Based Medicine. Chapel Hill, NC: Health Sciences Library, UNC-Chapel Hill. 2004. I DENTIFYING THE B EST S TUDY


36 C LINICAL Q UERIES Search by Clinical Study Category Category Etiology Diagnosis Therapy (default) Prognosis Clinical prediction Scope Narrow specific search Broad sensitive search(default) Systematic Reviews Medical Genetics Searches

37 S PECIAL Q UERIES Comparative Effectiveness Research Health Services Research (HSR) Queries Research Reporting Guidelines and Initiatives Veterinary Medicine/Animal Health

38 M E SH T ERMS Evidence Based Practice [MH] (under Health Occupations) Evidence-Based Dentistry Evidence-Based Medicine (also listed under (Clinical Medicine) Evidence-Based Emergency Medicine Evidence-Based Nursing

39 M E SH T ERMS Study Characteristics [PT] Case Reports Clinical Conference Clinical Trial + Comparative Study Census Development Conference (CDC) o CDC, NIH Evaluation Studies In Vitro Meta-Analysis Multicenter Study Scientific Integrity Review Twin Study Validation Studies

40 M E SH T ERMS Clinical Trial [PT] (under Study Characteristics) Clinical Trial, Phase I Clinical Trial, Phase II Clinical Trial, Phase III Clinical Trial, Phase IV Controlled Clinical Trial Multicenter Study Randomized Controlled Trial

41 M E SH T ERMS Useful in text words - use [TW] Blind Mask Random Placebo Efficacy Effective Crossover [mh] Cohort [mh]


43 Is the study valid? Are the results important? What were the results? Will the results help me in caring for my patients? Questions depend on the type of study being appraised Heneghan C, Badenoch D. Evidence-based medicine toolkit. 2d ed. Malden, MA: Blackwell, 2007

44 CONSORT – Consolidated Standards of Reporting Trials MOOSE – Meta-analysis of Observational Studies in Epidemiology QUORUM – Quality of Reporting for Meta-analysis STROBE – Strengthening the Reporting of Observations Studies in Epidemiology Brand RA. Standards of reporting: The CONSORT, QUORUM, and STROBE guidelines. Clin Orthop Relat Res. 2009 (467):1383-1394. R EPORTING S TANDARDS

45 C RITICAL A PPRAISAL E XAMPLE de Haen M, Spigt MG, van Uden CJ, van Neer P, Feron FJ, Knottnerus A. Efficacy of duct tape vs placebo in the treatment of verruca vulgaris (warts) in primary school children. Arch Pediatr Adolesc Med. 2006 Nov;160(11):1121-1125. Van Cleave J, Kemper AR, Davis MM. Interpreting negative results from an underpowered clinical trial: warts and all. Arch Pediatr Adolesc Med. 2006 Nov;160(11):1126-1129.

46 F OR M ORE I NFORMATION Centre for Evidence-Based Medicine - CEMB: EMB Tools (Centre for Health Evidence): Tools to support evidence-informed decision making ( EPIQ - Critical Appraisal and Evidence-based Practice (University of Auckland):


48 PUBMED and the EVIDENCE-BASED UNIVERSE Holly Ann Burt Outreach and Exhibits Coordinator NN/LM GMR

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