Systematic reviews designed to facilitate dissemination of information to practitioners
Nov. 17, 2011
By Maria Perno Goldie, RDH, MS
The 2nd North American Dental Hygiene Research Conference was held in October in Bethesda MD, adjacent to the campus of the National Institutes of Health (NIH). Jim Bader DDS, MPH, Research Professor, Operative Dentistry, University of North Carolina, presented an excellent course on Systematic Reviews. I will highlight some of the salient points in Dr. Bader’s presentation.(1) He was kind enough to share his information with the attendees. Thanks to Dr. Bader for an informative course. The presentation began with a background on dental knowledge, the rationale for systematic reviews, the steps in performing a systematic review, systematic review reporting guidelines, systematic review evaluation guidelines, and how one assesses the strength of the considered evidence. According to Dr. Bader, evidence is what the profession “knows”, or the dental knowledge base. This knowledge base is a store of specialized information on: diseases; treatment methods; and treatment outcomes. It is the basis of professional decision-making that has evolved over time with respect to: creation; synthesis; and dissemination of information. The dental knowledge base has evolved over the years. Phase 1 is considered the Age of the Expert, year 1750 forward. At the time there were itinerant dentists, no organized literature, and no schools. Phase 2 was the Age of Professionalization, 1750 to 1900. The profession saw textbooks appear, the first journal, the licensure process instituted, and the appearance of proprietary schools. Phase 3 brought the Age of Science, the years 1900 to 1990. We saw controlled experiments, university curricula, and literature reviews. Phase 4, the most current, is called the Age of Evidence, starting around 1990 until current time. We are witnessing stronger research, a focus on evidence and patient outcomes, and more reliance in the Internet.
The 2nd North American Dental Hygiene Research Conference was held in October in Bethesda MD, adjacent to the campus of the National Institutes of Health (NIH). Jim Bader DDS, MPH, Research Professor, Operative Dentistry, University of North Carolina, presented an excellent course on Systematic Reviews. I will highlight some of the salient points in Dr. Bader’s presentation.(1) He was kind enough to share his information with the attendees. Thanks to Dr. Bader for an informative course. The presentation began with a background on dental knowledge, the rationale for systematic reviews, the steps in performing a systematic review, systematic review reporting guidelines, systematic review evaluation guidelines, and how one assesses the strength of the considered evidence. According to Dr. Bader, evidence is what the profession “knows”, or the dental knowledge base. This knowledge base is a store of specialized information on: diseases; treatment methods; and treatment outcomes. It is the basis of professional decision-making that has evolved over time with respect to: creation; synthesis; and dissemination of information. The dental knowledge base has evolved over the years. Phase 1 is considered the Age of the Expert, year 1750 forward. At the time there were itinerant dentists, no organized literature, and no schools. Phase 2 was the Age of Professionalization, 1750 to 1900. The profession saw textbooks appear, the first journal, the licensure process instituted, and the appearance of proprietary schools. Phase 3 brought the Age of Science, the years 1900 to 1990. We saw controlled experiments, university curricula, and literature reviews. Phase 4, the most current, is called the Age of Evidence, starting around 1990 until current time. We are witnessing stronger research, a focus on evidence and patient outcomes, and more reliance in the Internet.
According to the American Dental Association (ADA), the definition of Evidence Based Dentistry is, “….an approach to oral health care that requires the judicious integration of systematic assessments of clinically relevant scientific evidence, relating to the patient's oral and medical condition and history, with the dentist's clinical expertise and the patient's treatment needs and preferences.”(2)As mentioned previously, the dental or dental hygiene knowledge base is what the profession currently knows. Systematic reviews are syntheses of specific subsets of the knowledge base, creating further evidence.(3) By definition, systematic reviews are reviews of the literature that are: focused on a specific clinical question; systematic in identification of the relevant literature; explicit in describing a review’s methods and objectives; reproducible and “transparent”; and are sources of valid information for clinical decision making.
Systematic reviews are designed to facilitate dissemination to practitioners. They are: focused clinical question; identify the type(s) of patients considered in a study; a synopsis of relevant characteristics of included studies; and an assessment of the strength of the evidence available to answer the posed question. They are designed to reduce bias found in traditional literature reviews.There are certain steps in a systematic review. They are to: 1) formulate a key clinical question; 2) provide and disclose inclusion and exclusion criteria; 3) develop a search strategy; conduct the search and select relevant studies; and 4) extract data from those studies; analyze and present the results; and to interpret the review results. The first step is to formulate the clinical question to which you need an answer. This is created by the use of a PICO design; P is the population or patient type; is the intervention or exposure; C is the comparison or control; and O is the outcome. The second step is establishing inclusion and exclusion criteria. This involves: the key question PICO elements; details of the population or subject eligibility; information on the treatment procedures; particulars of the evaluation procedures; the language(s) desired; the publication date range; and the type of study or study design.(4)
Regarding the design of studies, there are: randomized controlled trials (RCTs); longitudinal observational studies, such as prospective cohort, case-control, retrospective cohort; and case; cross-sectional studies; and expert opinion.(5) The search may include a variety of databases and electronic indices, such as MEDLINE, EMBASE, LILACS, CINAHL, or Google Scholar. The Cochrane library reviews, DARE, and CENTRAL may be accessed, and “hand” searching in current and non-indexed journals. Reference listings may be explored, as well as the gray literature, including such items as theses, dissertations, conference reports, abstracts, and unpublished studies. When the search is complete, the reviewers apply the inclusion and exclusion criteria set at the start of the systematic review. Two reviewers complete the process independently, and rules for resolving disagreements are set ahead. It is usually conducted in two stages, first an assessment of the title and abstract, and then an appraisal of the full paper. A log of reasons for exclusion is provided.When extracting the data from the designated studies, an evidence table is used. It is populated with detailed information about the research design, the subjects; the methods used, and the results. The results are then analyzed and presented. In addition to the evidence summary tables, presented is a qualitative summary with a brief description of the studies, a risk of bias assessment (methodological quality), and heterogeneity of PICO elements, and a narrative summary of the results. A quantitative summary is also provided, with a meta-analysis, meta-regression, and a sensitivity analysis. The systematic review is then interpreted, taking into account the limitations of the review and the strength of the evidence. The strength of the evidence is determined by the quantity of studies reviewed, the number of subjects (or “n”) in each study; and the sample sizes. The quality and consistency of the results are considered, and implications for needed research and for the clinician are identified.One of the final steps is reporting the results of the review.(6) Evaluate the methodological quality of a systematic review, with AMSTAR.(7)
Strength of the Evidence. Modified SORT criteria.(8)
This is just a small portion of what is available in the literature. For a DATABASE OF SYSTEMATIC REVIEWS that are clinically relevant to healthcare in dental settings and is categorized by clinical topic, go to the ADA Center for Evidence-Based Dentistry.(2) References
1. Bader J. Presentation “Introduction to Systematic Reviews”. 2nd North American Dental Hygiene Research Conference, Bethesda MD, October 22, 2011.2. ebd.ada.org/SystematicReviews.aspx. 3. Bader J and Ismail A. Survey of systematic reviews in dentistry. JADA, April 1, 2004 vol. 135 no. 4 464-473.4. Egger M, Davey Smith G, Altman D, eds. Systematic reviews in health care: meta-analysis in context. London, BMJ Publishing Group, 2001. 5. www.thecre.com/pdf/ahrq-system-strength.pdf.6. “Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement” . Moher et al, Ann Internal Med 2009;151:264-9). QUOROM, PRISMA. The PRISMA Statement contains Guidelines For Performing A Systematic Review: paper, checklist, flowchart, and explanation. www.prisma-statement.org/.7. Shea B, Grimshaw J, Wells G, et al. Development of AMSTAR: a Measurement Tool to Assess the Methodological Quality of Systematic Reviews. BMC Med Res Method 2007;7:10). www.biomedcentral.com/content/pdf/1471-2288-7-10.pdf.8. Ebell MH, Siwek J, Weiss BD, Woolf SH, Susman J, Ewigman B, et al. Strength of Recommendation Taxonomy (SORT): a patient-centered approach to grading evidence in the medical literature. Am Fam Physician 2004;69:549-57. www.aafp.org/online/en/home/publications/journals/afp/afpsort.html.
1. Bader J. Presentation “Introduction to Systematic Reviews”. 2nd North American Dental Hygiene Research Conference, Bethesda MD, October 22, 2011.2. ebd.ada.org/SystematicReviews.aspx. 3. Bader J and Ismail A. Survey of systematic reviews in dentistry. JADA, April 1, 2004 vol. 135 no. 4 464-473.4. Egger M, Davey Smith G, Altman D, eds. Systematic reviews in health care: meta-analysis in context. London, BMJ Publishing Group, 2001. 5. www.thecre.com/pdf/ahrq-system-strength.pdf.6. “Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement” . Moher et al, Ann Internal Med 2009;151:264-9). QUOROM, PRISMA. The PRISMA Statement contains Guidelines For Performing A Systematic Review: paper, checklist, flowchart, and explanation. www.prisma-statement.org/.7. Shea B, Grimshaw J, Wells G, et al. Development of AMSTAR: a Measurement Tool to Assess the Methodological Quality of Systematic Reviews. BMC Med Res Method 2007;7:10). www.biomedcentral.com/content/pdf/1471-2288-7-10.pdf.8. Ebell MH, Siwek J, Weiss BD, Woolf SH, Susman J, Ewigman B, et al. Strength of Recommendation Taxonomy (SORT): a patient-centered approach to grading evidence in the medical literature. Am Fam Physician 2004;69:549-57. www.aafp.org/online/en/home/publications/journals/afp/afpsort.html.
Maria Perno Goldie, RDH, MS
To read previous articles in RDH eVillage FOCUS from 2011 written by Maria Perno Goldie, go to articles.
