Evidence Based Chronic Disease Prevention Module Four: Scientific Literature Review

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Evidence Based ChronicDisease Prevention
Module Four Scientific Literature Review

• Presented by Karen Peters, DrPH

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Objectives

• Determine what is a literature review and why
  they are useful.
• Delineate the differences between the 3 types of
  literature review.
• Identify commonly used databases and web
  resources used in conducting a literature review.

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Literature Reviews What Are They and Are They
Useful?

• A literature review is a type of scientific
  research article published in a professional
  peer-reviewed journal.
• The purpose of a literature review is to
  appropriately report on the state of knowledge
  that exists from previously published research.

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Literature Reviews What Are They and Are They
Useful?

• The literature review research design is
  different from other research designs because it
  studies previously published research papers.
• Literature reviews are useful because they
  summarize several studies in one paper, thereby
  reducing the number of papers that a busy public
  health practitioner has to read in order to learn
  new information

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The 3 Types of Literature Reviews

• Narrative Literature Review
• Qualitative Systematic Literature Review
• Quantitative Systematic Literature Review
  (Meta-analysis)

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Narrative Literature Review

• Definition
• This type of review is a narrative overview of a
  topic based upon published literature.
• Strengths
• They are helpful in presenting a broad
  perspective on a topic and often describe the
  history or development of a problem or its
  management.
• They often discuss theory and context and used
  for educational purposes.
• Use to provoke thought and are useful pieces to
  read when there is little research available on a
  topic.
• Papers often incite a call to action.

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Narrative Literature Review

• Limitations
• Lack of reproducible methods sometimes employed
  to construct them.
• Reviews are sometimes quite biased, making it
  difficult to discern if the author has
  constructed a review of the literature or a
  commentary.
• Since these reviews deal with theory and
  overviews, they may not be the right choice if
  you are trying to answer practice/intervention
  related questions.
• Rarely appraise the quality of articles used in
  the literature review but make comments from the
  reviewed literature.

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Narrative Literature Review

• Identifying Features
• Key identifying feature is their prose nature
  with a general de-emphasis of reproducible
  methodology and an emphasis on synthesizing
  information.
• Author typically writes a summary abstract of the
  article that does not delineate the methods used
  to find the articles reviewed.
• If the abstract is structured the methods are
  still not clearly described and detailed.

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Narrative Literature Review

• Level of Evidence
• Narrative literature reviews are one of the
  weakest forms of evidence to use for making
  program/practice related decisions.

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Sample Narrative LiteratureReview Abstract

• Selected Evidence for Behavioral Approaches to
  Chronic Management in Clinical Settings Diabetes
• Author Center for Advancement of Health Health
  Behavior Change in Managed Care Advisory
  Committee
• Published 2000
• http//www.cfah.org/

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Qualitative SystematicLiterature Review

• Definition
• A systematic review is a type of literature
  review that employs detailed rigorous and
  explicit methods.
• The authors of systematic reviews attempt to
  obtain all original (primary) research studies
  published on the topic under study by searching
  in multiple databases and performing hand
  searches.
• The authors appraise each paper reviewed in a
  systematic and consistent manner
• Qualitative systematic reviews of the literature
  are called qualitative because the process by
  which the individual studies are integrated
  includes a summary of findings, but does not
  statistically combine the results of all of the
  studies reviewed

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Qualitative SystematicLiterature Review

• Strengths
• Usually structured around a focused question or
  purpose, allowing the authors to develop criteria
  used to determine if a research publication
  should be included or excluded in the final
  synthesis.
• Methods of the study are written in a
  reproducible manner, so that you could replicate
  the study if you wished ? this enhances the
  credibility of the study.

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Qualitative Systematic Literature Review

• Limitations
• Most suitable for reviewing clinical trials and
  observational types of studies, such as cohort
  designs.
• Do not really allow for much discussion of theory
  and its application.
• Lack of statistical analysis precludes the
  assessment of relative strength of various studies

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Qualitative Systematic Literature Review

• Identifying Features
• A detailed search of the literature based upon a
  focused question or purpose is the hallmark of a
  systematic review.
• Abstract will typically be structured and
  describe the methodology employed, including the
  inclusion/exclusion criteria.
• Several databases will have been searched and
  should be divulged, including the search dates
  and search words.

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Qualitative Systematic Literature Review

• Identifying Features
• Authors critically analyze the research reviewed
  and this analysis is reported in a synthesized
  manner based on the information extracted during
  the review.
• Each paper may be rated on a scoring system by
  the authors.
• Results will be presented in a systematic
  fashion, but the results of several studies
  reviewed will not be statistically combined.

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Qualitative Systematic Literature Review

• Level of Evidence
• More powerful evidence-based source to garner
  practice related information than narrative
  reviews, case reports, case series and poorly
  conducted cohort studies.

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Sample Qualitative Systematic Literature Review
Abstract

• Effectiveness of Self-Management Training in Type
  2 Diabetes
• Authors Susan L. Norris, MD, MPH Michael M.
  Engelgau, MD, MSc K.M. Venkat Narayan, MD, MPH
• Journal Diabetes Care
• Publication Date 2001
• Volume 24, pages 561 - 587

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Quantitative SystematicLiterature Review

• Definition
• A systematic review that critically evaluates
  each paper reviewed and statistically combines
  the results of the studies is called a
  quantitative systematic review of the literature,
  or meta-analysis.
• Meta-analysis employ all of the rigorous
  methodology of qualitative systematic reviews.
• Are called quantitative because the process by
  which the individual studies are integrated
  includes a summary of findings and also utilizes
  statistical methods to pool data from the various
  studies.

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Quantitative SystematicLiterature Review

• Strengths
• Inherent strengths common to systematic review
  process.
• The major benefit of a meta-analysis is the
  pooling of data between studies. This allows
  authors to derive a large base of data from which
  to draw a conclusion.
• Particularly powerful if studies under review are
  very similar in their construction because
  several studies can be combined as one larger
  base of data leading to more powerful conclusions.

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Quantitative Systematic Literature Review

• Limitations
• The big strength of the meta-analysis, the
  pooling of the data, can also be a drawback
  because it is difficult to find studies that are
  similar enough to one another to draw valid
  comparisons.
• There is disagreement amongst experts about the
  most appropriate methods to combine the data from
  studies with different variables (populations,
  outcome measures, interventions).
• Meta-analyses do not really allow for much
  discussion of theory and its application.

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Quantitative Systematic Literature Review

• Identifying Features
• Like the qualitative systematic review, look for
  explicit and reproducible methodology.
• Results presented in a systematic fashion and the
  results of several studies reviewed should be
  statistically combined.
• Each paper may be rated on a scoring system by
  the authors.

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Quantitative Systematic Literature Review

• Identifying Features
• Authors critically analyze the research reviewed
  and this analysis is reported in a synthesized
  manner based on the information extracted during
  the review.
• Each paper may be rated on a scoring system by
  the authors.
• Results will be presented in a systematic
  fashion, but the results of several studies
  reviewed will not be statistically combined.

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Quantitative Systematic Literature Review

• Level of Evidence
• Meta-analyses are considered to be a very high
  form of evidence for making practice/intervention
  related decisions.
• The results of the review are produced from a
  rigorous critical appraisal of previously
  published research as well as the pooling of data
  from the studies.
• This leads to a large database from which to draw
  conclusions.

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Sample Quantitative Systematic Literature Review
Abstract

• Meta-Analysis of Diabetes Patient Education
  Research Variation in Intervention Effects
  across Studies
• Author Sharon A. Brown, PhD, RN
• Journal Research in Nursing and Health
• Publication Date 1992
• Volume 15, pages 409-419

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Databases Commonly Used

• Common databases in USA
• CDC
• NIH
• MEDLARS
• MEDLINE
• PubMed
• CancerLit
• Current Contents
• HealthSTAR

• Common databases in IL
• IDPH
• IPLAN
• Vital records
• Hospital discharge (IH4C)
• Traffic safety related database

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Commonly Used Internet Resources

• Common Internet Databases in USA
• Centers for Disease Control and Prevention
  http//www.cdc.gov/
• National Institutes of Health http//www.nih.gov/
  
• this will be expanded!!

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Literature Review Key sources

• List of books and journals
• U.S. Government printing office
  (www.access.gpo.gov )

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Demonstration Emulating a Search

• National Library of Medicine
• www.nlm.nih.gov
• PubMed
• http//www.ncbi.nlm.nih.gov/entrez/query.fcgi

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Demonstration Emulating a Search
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Demonstration Emulating a Search
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Demonstration Emulating a Search
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Demonstration Emulating a Search
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Demonstration Emulating a Search
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Demonstration Emulating a Search