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Presentation of Findings
- 1. Presentation of FindingsPrepared for: The Agency for Healthcare Research and Quality (AHRQ) Training Modules for Systematic Reviews Methods Guide www.ahrq.gov
- 2. Systematic Review ProcessOverview
- 3. To understand thegoals of presenting systematic review data in tables that summarize data across studies To become familiar with approaches to graphical presentations of findings not synthesized through statistical or meta-analytic techniques Learning Objectives
- 4. Once the evidencetables are completed, there is an enormous (sometimes overwhelming) amount of data yet to synthesize. Various types of heterogeneity may preclude a quantitative synthesis (e.g., meta-analysis). Synthesizing heterogeneous studies by using tables (nonquantitative synthesis) can capture underlying similarities to support conclusions. Making sense of the data requires good tabular presentation, in addition to clear organization and writing of the text. Organizing and Reporting Findings
- 5. Even studies meetingthe same inclusion criteria can vary. Clinical heterogeneity — variation in the study population, interventions, and outcomes Methodological heterogeneity — variation in study design Statistical heterogeneity — variation in observed treatment effect (for trials) Many factors can contribute to variation in seemingly similar studies. Some examples are evolving diagnostic criteria, evolving diseases, differences in baseline characteristics, and differences in care. Not all studies can (or should) be combined statistically. Various statistical models are useful for identifying the level of heterogeneity between studies. Why Not Meta-analysis? AHRQ . Methods reference guide for effectiveness and comparative effectiveness reviews . Version 1.0. Available at: http://effectivehealthcare.ahrq.gov/repFiles/2007_10DraftMethodsGuide.pdf.
- 6. Nonquantitative synthesis usingtables that summarize data across studies Use of evidence maps to provide an overview of the data Solution
- 7. Population: primarypopulations of interest are followed by subpopulations Intervention: hierarchy of interventions may reflect most common to least common Comparator: where multiple comparisons are made, one might present the more “usual” decision first Outcome: a hierarchy of outcomes may reflect higher to lower acuity or target outcomes followed by collateral ones; harms are generally presented last Timing: short term generally precedes long term Setting: an intervention may be available in various settings (e.g., inpatient or outpatient) PICOTS
- 8. Evidence tables arethe first step to summarization, but each evidence table represents the data in only one study. Incorporating multiple studies into a single table allows entire subsets of the literature to be summarized and compared (e.g., by key question or study design). Summary tables and evidence maps are two approaches with which information about individual studies and results are combined. Authors should use caution when deciding which evidence to summarize so as not to introduce a biased perspective. Combining Studies
- 9. Combine data frommultiple studies to illustrate trends in the data May be focused on describing study characteristics, results, or both Can be designed to include characteristics of all included studies Examples: funding sources, assessment method, country of study Can be designed for subsets of included studies Examples: summary tables for randomized controlled trials, prevalence studies, harms/side effects, outcomes for specific treatments Summary Tables (I)
- 10. Simplified entry (onerow) for each study Table columns may include, for example: PICOTS (may be listed in table title or headers) Methodological quality Applicability Study size (weight) Magnitude of effect A single study may be represented in multiple summary tables (e.g., different outcomes) Summary Tables (II) PICOTS = population, intervention, comparator, outcomes, timing, and setting
- 11. Example: Summary Tableof Study Characteristics A basic summary table is the “study characteristics” table. The overall summary provides an overview of the state of the available studies in the literature. Hartmann KE, et al. AHRQ Evidence Report/Technology Assessment No. 187. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/ bladder/bladder.pdf.
- 12. Example: Summary Tableas High-Level Map Chung M, et al. AHRQ Evidence Report/Technology Assessment No. 183. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/vitadcal/vitadcal.pdf.
- 13. Example: Summary Tableof Study Characteristics Balk EM, et al. Ann Intern Med 2003;139:670-82. Reprinted with permission from the American College of Physicians.
- 14. Visual Presentation ofAvailable Comparisons Ip S, et al. AHRQ Evidence Report/Technology Assessment No. 124. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/rhinoupdate/rhinoup.pdf.
- 15. Example: Summary Tableof Prevalence Findings Summary tables can be specialized for different types of questions. Hartmann KE, et al. AHRQ Evidence Report/Technology Assessment No. 187. Available at: http://www.ahrq.gov/ downloads/pub/evidence/ pdf/ bladder/bladder.pdf.
- 16. Example: Summary Tablefor Randomized Controlled Trials Summary tables can be specialized for different subgroups of the literature. Hartmann KE, et al. AHRQ Evidence Report/Technology Assessment No. 187. Available at: http://www.ahrq.gov/ downloads/pub/evidence/pdf/bladder/bladder.pdf.
- 17. Example: SummaryTable for Cohort Studies Wang C, et al. AHRQ Evidence Report/Technology Assessment No. 94. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/o3cardio/o3cardio.pdf.
- 18. Example: Presentation ofHarms Data Summary tables can be specialized for different subgroups of the literature. Hartmann KE, et al. AHRQ Evidence Report/Technology Assessment No. 187. Available at: http://www.ahrq.gov/ downloads/pub/evidence/ pdf/ bladder/bladder.pdf.
- 19. Example: Presentation ofData by Outcome and Age Chung M, et al. AHRQ Evidence Report/Technology Assessment No. 183. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/vitadcal/vitadcal.pdf.
- 20. Example: Presentation ofPatient-Reported Outcomes Summary tables can be specialized for different types of outcomes. Hartmann KE, et al. AHRQ Evidence Report/Technology Assessment No. 187. Available at: http://www.ahrq.gov/ downloads/pub/evidence/ pdf/ bladder/bladder.pdf.
- 21. Are a succinctgraphical presentation of available studies to address key questions along variables of interest Results of outcomes typically not included Can help to identify comparisons with sufficient evidence for analysis Can help to guide readers in knowing what comparisons and outcomes are available in the report Can help to identify evidence gaps Evidence Maps
- 22. Example: Evidence MapTerasawa T, et al. Ann Intern Med 2009;151:556-65. Reprinted with permission from the American College of Physicians.
- 23. A Second Approachto an Evidence Map Raman G, et al. AHRQ Technology Assessment No. GEND1206. Available at: http://www.cms.gov/determinationprocess/downloads/id61TA.pdf. Dt: time (to stable dose) INR: international normalized ratio mean dose: mean maintenance dose
- 24. Forest Plot WithoutSummary Favors Wide-Area Circumferential Ablation Favors Pulmonary Vein Isolation Ip S, et al. AHRQ Comparative Effectiveness Review No. 15. Available at: http://www.effectivehealthcare.ahrq.gov/ehc/products/51/114/2009_0623RadiofrequencyFinal.pdf.
- 25. Summary Matrix WangC, et al. AHRQ Evidence Report/Technology Assessment No. 94. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/o3cardio/o3cardio.pdf.
- 26. Summary tables andevidence maps provide key information on study characteristics and study findings. Through table and graphical formats, respectively Properly constructed summary tables: Effectively convey results Provide an overview of the literature in a given field Enable the reader to grasp results for subsets of the literature Key Messages
- 27. Agency for HealthcareResearch and Quality. Methods reference guide for effectiveness and comparative effectiveness reviews. Version 1.0. Rockville, MD: Agency for Healthcare Research and Quality, Draft Posted October 2007. Chapter 2, Finding evidence. Available at: http://effectivehealthcare.ahrq.gov/repFiles/ 2007_10DraftMethodsGuide.pdf. Balk EM, Lau J, Goudas LC, et al. Effects of statins on nonlipid serum markers associated with cardiovascular disease. Ann Intern Med 2003;139:670-82. Chung M, Balk EM, Brendel M, et al. Vitamin D and Calcium: A Systematic Review of Health Outcomes. Evidence Report/Technology Assessment No. 183. (Prepared by Tufts–New England Medical Center Evidence-based Practice Center under Contract No. HHSA 290-2007-10055-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E015. Available at: http://www.ahrq.gov/downloads/pub/ evidence/pdf/vitadcal/vitadcal.pdf. References (I)
- 28. Hartmann KE, McPheetersML, Biller DH, et al. Treatment of Overactive Bladder in Women . Evidence Report/Technology Assessment No. 187 (Prepared by Vanderbilt University Evidence-based Practice Center under Contract No. 290-2007-10065-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E017. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/bladder/ bladder.pdf. Ip S, Fu L, Balk E, et al. Update on Acute Bacterial Rhinosinusitis . Evidence Report/Technology Assessment No. 124. (Prepared by Tufts – New England Medical Center Evidence-based Practice Center under Contract No. 290-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, June 2005. AHRQ Publication No. 05-E020-2. Available at: http://www.ahrq.gov/downloads/pub/ evidence/pdf/rhinoupdate/rhinoup.pdf . References (II)
- 29. Ip S, TerasawaT, Balk EM, et al. Comparative Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation . Comparative Effectiveness Review No. 15 (Prepared by Tufts –New England Medical Center Evidence-based Practice Center under Contract No. 290-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, July 2009. AHRQ Pub. No. 09-EHC015-EF. Available at: http://www.effectivehealthcare.ahrq.gov/ ehc/products/51/114/2009_0623RadiofrequencyFinal.pdf. Raman G, Trikalinos TA, Zintzaras E, et al. Reviews of Selected Pharmacogenetic Tests for Non-Cancer and Cancer Conditions . Technology Assessment No. GEND1206 (Prepared by Tufts – New England Medical Center Evidence-based Practice Center under Contract No. 290-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, November 2008. Available at: http://www.cms.gov/determinationprocess/downloads/id61TA.pdf. References (III)
- 30. Terasawa T, DvorakT, Ip S, et al. Systematic review: charged-particle radiation therapy for cancer. Ann Intern Med 2009;151:556-65. Wang C, Chung M, Balk E, et al. Effects of Omega-3 Fatty Acids on Cardiovascular Disease. Evidence Report/Technology Assessment No. 94 (Prepared by Tufts –New England Medical Center Evidence-based Practice Center under Contract No. 209-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, March 2004. AHRQ Publication No. 04-E009-2. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/o3cardio/o3cardio.pdf. References (IV)
- 31. This presentation wasprepared by Melissa L. McPheeters, Ph.D., M.P.H., and Jeff Seroogy, B.S., members of the Vanderbilt University Evidence-based Practice Center, and Joseph Lau, M.D., and Thomas Trikalinos, M.D., Ph.D., members of the Tufts Medical Center Evidence-based Practice Center. The information in this module is currently not included in Version 1.0 of the Methods Guide for Comparative Effectiveness Reviews (available at: http://www.effectivehealthcare.ahrq.gov/ehc/ products/60/294/2009_0805_principles1.pdf). Authors
Editor's Notes
- #2 Presentation of Findings
- #3 Systematic Review Process Overview This slide illustrates the steps in the systematic review process. This module focuses on the presentation of findings.
- #4 Learning Objectives
- #5 Organizing and Reporting Findings Identifying the analytic framework, key questions, and inclusion/exclusion criteria is important for gathering data, but presenting it in an efficient and intuitive manner is equally important, if not more so. Evidence tables are an integral part of the presentation, but they refer only to individual studies. Synthesizing information from multiple studies is crucial for producing useful conclusions. We discuss how and when to synthesize data and the summary tables used to illustrate this synthesized information.
- #6 Why Not Meta-analysis? There are many factors that contribute to the decision about whether or not studies can be combined. Reference: Agency for Healthcare Research and Quality. Methods reference guide for effectiveness and comparative effectiveness reviews . Version 1.0. Rockville, MD: Agency for Healthcare Research and Quality, Draft Posted October 2007. Chapter 2, Finding evidence. Available at: http://effectivehealthcare.ahrq.gov/repFiles/2007_10DraftMethodsGuide.pdf.
- #7 Solution Synthesizing a body of literature in a nonquantitative way requires the use of well-constructed and intuitive summary tables and highly structured text to support their interpretations. At the simplest level, it is always the case that presenting results in a structured, uniform manner makes it easier for readers to locate and apply findings. The sheer quantity of data and potential heterogeneity in the context of a systematic review raise this work to a higher level of complexity. Establishing a common pattern in presenting data throughout a report is one principle that can improve clarity and flow. The text mirrors and expands on summary tables that visually illustrate findings and commonalities in the evidence by condensing results from different studies into a single table without combining the data statistically. Reviewers in the Evidence-based Practice Centers typically use several types of tables, several examples of which are shown later in this presentation.
- #8 PICOTS This slide provides a breakdown of PICOTS and gives examples for using these components to organize results.
- #9 Combining Studies
- #10 Summary Tables (I) Summary tables cover groups of studies rather than the individual studies represented in evidence tables.
- #11 Summary Tables (II) The following slides provide examples of summary tables. Information is put together in tabular form, and the important characteristics and results of studies are readily available. There is no required format for summary tables. The key is to find the best construction to highlight the summary or particular data points.
- #12 Example: Summary Table of Study Characteristics Reviews will usually have several different types of summary tables presented and discussed in the text. At least one overview table such as this one should be included, either for the entire body of literature or for each key question. No results of studies are presented here; rather, the intent is to characterize the literature in terms of variables such as study design, geographic location, funding source, and other study characteristics. Reference: Hartmann KE, McPheeters ML, Biller DH, et al. Treatment of Overactive Bladder in Women . Evidence Report/Technology Assessment No. 187 (Prepared by Vanderbilt University Evidence-based Practice Center under Contract No. 290-2007-10065-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E017. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/bladder/bladder.pdf.
- #13 Example: Summary Table as High-Level Map This example is of a table that can help the reader navigate large reports, by using an overall summary table to convey high-level information. In a sense, this is a high-level map: what was compared to what, what was measured, and in what types of studies. Reference: Chung M, Balk EM, Brendel M, et al. Vitamin D and Calcium: A Systematic Review of Health Outcomes . Evidence Report/Technology Assessment No. 183. (Prepared by Tufts–New England Medical Center Evidence-based Practice Center under Contract No. HHSA 290-2007-10055-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E015. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/vitadcal/vitadcal.pdf.
- #14 Example: Summary Table of Study Characteristics The overall summary table does not provide significant detail but is broad in its scope. For example, in this table, treatment effects are denoted as “+” or “−”. Detailed exposition per study is given in the evidence tables, which are presented in the module on data extraction. Reference: Balk EM, Lau J, Goudas LC, et al. Effects of statins on nonlipid serum markers associated with cardiovascular disease. Ann Intern Med 2003;139:670-82. http://www.ncbi.nlm.nih.gov/pubmed/14568856
- #15 Visual Presentation of Available Comparisons It is often useful to visualize the availability of evidence addressing specific questions or comparisons within the comparative effectiveness or systematic review. In some settings, we may be inundated with a large number of studies and myriad comparisons. A matrix, as shown in this slide, could be constructed to depict the various comparisons that have been reported and the number of studies that have reported them. Such an “evidence map” could be used to help appreciate the scope of the evidence and to identify opportunities for meta-analyses. This slide comes from a 2005 evidence report update on acute bacterial rhinosinusitis. Reference : Ip S, Fu L, Balk E, et al. Update on Acute Bacterial Rhinosinusitis . Evidence Report/Technology Assessment No. 124 (Prepared by Tufts – New England Medical Center Evidence-based Practice Center under Contract No. 290-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, June 2005. AHRQ Publication No. 05-E020-2. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/rhinoupdate/rhinoup.pdf.
- #16 Example: Summary Table of Prevalence Findings In addition to providing an overview, summary tables can be used to subset groups of studies or to highlight specific outcomes. For example, this case summary table was created for a key question about prevalence; therefore, it included only studies with prevalence data. In addition to presenting the prevalence data, columns were selected to reflect those characteristics that are important for assessing the strengths and limitations of studies that attempt to measure prevalence. Reference: Hartmann KE, McPheeters ML, Biller DH, et al. Treatment of Overactive Bladder in Women . Evidence Report/Technology Assessment No. 187 (Prepared by Vanderbilt University Evidence-based Practice Center under Contract No. 290-2007-10065-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E017. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/bladder/ bladder.pdf.
- #17 Example: Summary Table for Randomized Controlled Trials Summary tables may be used to highlight results from specific study types. This table presents baseline and outcomes data only for the randomized controlled trials of one drug, oxybutynin, with a focus on one outcome, urge incontinence. Reference: Hartmann KE, McPheeters ML, Biller DH, et al. Treatment of Overactive Bladder in Women . Evidence Report/Technology Assessment No. 187 (Prepared by Vanderbilt University Evidence-based Practice Center under Contract No. 290-2007-10065-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E017. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/bladder/ bladder.pdf.
- #18 Example: Summary Table for Cohort Studies Here is a presentation of the cohort studies available in a review of the effects of omega-3 fatty acids on cardiovascular disease. This table also incorporates the quality scores that were applied to the studies and a measure of their applicability in practice. Reference: Wang C, Chung M, Balk E, et al. Effects of Omega-3 Fatty Acids on Cardiovascular Disease. Evidence Report/Technology Assessment No. 94 (Prepared by Tufts–New England Medical Center Evidence-based Practice Center under Contract No. 209-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, March 2004. AHRQ Publication No. 04-E009-2. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/o3cardio/o3cardio.pdf.
- #19 Example: Presentation of Harms Data Presentation of harms data can be challenging. This example table presents the range of proportions of individuals experiencing a given set of harms and the number of studies that provided data for the range. Reference: Hartmann KE, McPheeters ML, Biller DH, et al. Treatment of Overactive Bladder in Women . Evidence Report/Technology Assessment No. 187 (Prepared by Vanderbilt University Evidence-based Practice Center under Contract No. 290-2007-10065-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E017. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/bladder/bladder.pdf.
- #20 Example: Presentation of Data by Outcome and Age This is another way to present the available evidence per outcome and life stage. Shaded areas mean that the specific outcome/life stage combination was not reviewed because it was not meaningful to do so. Reference: Chung M, Balk EM, Brendel M, et al. Vitamin D and Calcium: A Systematic Review of Health Outcomes . Evidence Report/Technology Assessment No. 183. (Prepared by Tufts–New England Medical Center Evidence-based Practice Center under Contract No. HHSA 290-2007-10055-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E015. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/vitadcal/vitadcal.pdf.
- #21 Example: Presentation of Patient-Reported Outcomes In some cases, bodies of literature present few common outcomes across studies. This is often the case in fields where there may be many relevant outcomes or multiple ways to assess the outcomes (e.g., multiple quality of life measures). A more text-intensive table, such as this one, can be used to describe outcomes in the literature. Reference: Hartmann KE, McPheeters ML, Biller DH, et al. Treatment of Overactive Bladder in Women . Evidence Report/Technology Assessment No. 187 (Prepared by Vanderbilt University Evidence-based Practice Center under Contract No. 290-2007-10065-I). Rockville, MD: Agency for Healthcare Research and Quality, August 2009. AHRQ Publication No. 09-E017. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/bladder/bladder.pdf.
- #22 Evidence Maps Evidence maps are another way to present data graphically without synthesizing them quantitatively through statistical approaches to combining data.
- #23 Example: Evidence Map This slide presents an evidence map of the available clinical research on charged particle beam radiotherapy for cancer. One can readily appreciate the number of studies conducted — stratified by cancer type, designs, and outcomes — while getting a sense of their relative sample sizes. Rows represent different cancer types. Super columns (separated by thicker vertical lines) stand for research designs (randomized controlled trials [RCTs], nonrandomized comparative studies, and noncomparative studies). Small columns denote outcomes (overall survival, cancer-specific survival, or other outcomes). Markers (empty circles) stand for published studies; their area is proportional to the sample size, and they have been jittered a bit to enhance visibility. The total number in each cell is shown in the lower right corner. See how few RCTs there are; they are relatively small and cover cancer types that are not very common. The same is true for nonrandomized comparative studies. Reference: Terasawa T, Dvorak T, Ip S, et al. Systematic review: charged-particle radiation therapy for cancer. Ann Intern Med 2009;151:556-65. http://www.ncbi.nlm.nih.gov/pubmed/19755348
- #24 A Second Approach to an Evidence Map This evidence map makes evident how selective the reporting was in a pharmacogenetics review: Meta-analysis is limited to whatever data are reported in published studies. Often, readers of a systematic review do not realize how selective a view this is. Here there are 21 single nucleotide polymorphisms (SNPs) in VKORC1 (a gene implicated in the metabolism of warfarin) that have been studied for associations with a variety of outcomes in different populations. Rows represent SNPs. Outcome super columns (defined by thicker vertical lines labeled “INR<2,” “INR>3” and so on) represent surrogate outcomes. Within each outcome super column, fine columns represent the 23 distinct ethnic-descent population strata in the included studies. Empty cells indicate that the corresponding SNP (row) has not been studied in the corresponding population (fine column) for the outcome of the super column. Colored cells indicate that the corresponding association has been studied and that it was reported to be statistically nonsignificant (black) or significant (red or blue, depending upon the direction of the association), or that the study did not report the respective significance. In theory, one can perform a meta-analysis when there are many filled cells across a row/SNP in a super column/outcome. Look at the emptiness of the table and how “selected” the meta-analyses that we can conduct in this field are. This slide shows only surrogate outcomes. The corresponding table for the clinical outcomes (e.g. serious bleeding) does not have any filled cells. The “minor allele” is the less frequent of the two alleles in the population. We coined the genetic comparisons by considering as a “variant allele” the allele with the lowest frequency (i.e., the minor allele) in populations of European descent to ensure correct representation of the direction of the genetic effects. The color code of each cell is based on what is reported by each study. Statistical significance status in the primary studies could be based on different analyses (e.g., haplotype-based analyses or adjusted analyses) than the ones we performed in this technology assessment. Reference: Raman G, Trikalinos TA, Zintzaras E, et al. Reviews of Selected Pharmacogenetic Tests for Non-Cancer and Cancer Conditions . Technology Assessment No. GEND1206 (Prepared by Tufts–New England Medical Center Evidence-based Practice Center under Contract No. 290-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, November 2008. Available at: http://www.cms.gov/determinationprocess/downloads/id61TA.pdf.
- #25 Forest Plot Without Summary In addition to summary tables and evidence maps, we suggest two other approaches to graphic presentation of data in comparative effectiveness or systematic reviews: the forest plot and the summary matrix. A forest plot is often used in presenting meta-analysis data, but it can also be useful when we are not combining studies statistically. In this example, a decision was made not to conduct a meta-analysis because of too much interstudy clinical heterogeneity. Rather, the results were presented graphically in a forest plot without a summary synthesis. This is an alternative presentation of study-level effects that can be combined with a summary table. This type of summary could tempt readers to draw a mental summary effect, so its purpose should be stated clearly in the corresponding legend. Reference: Ip S, Terasawa T, Balk EM, et al. Comparative Effectiveness of Radiofrequency Catheter Ablation for Atrial Fibrillation . Comparative Effectiveness Review No. 15 (Prepared by Tufts–New England Medical Center Evidence-based Practice Center under Contract No. 290-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, July 2009. AHRQ Pub. No. 09-EHC015-EF. Available at: http://www.effectivehealthcare.ahrq.gov/ehc/products/51/114/2009_0623RadiofrequencyFinal.pdf.
- #26 Summary Matrix A summary matrix such as this one shows the relationship between the methodological quality of the studies and their applicability in practice. Usually, the studies with the best methodological quality (a proxy for studies with the least susceptibility to bias) are not the ones that have the best applicability (a proxy for how generalizable the findings are to the key question or population of interest). This is exemplified by a quality-applicability summary matrix. The least-biased studies may not be applicable to the population of interest. Reference: Wang C, Chung M, Balk E, et al. Effects of Omega-3 Fatty Acids on Cardiovascular Disease. Evidence Report/Technology Assessment No. 94 (Prepared by Tufts –New England Medical Center Evidence-based Practice Center under Contract No. 209-02-0022). Rockville, MD: Agency for Healthcare Research and Quality, March 2004. AHRQ Publication No. 04-E009-2. Available at: http://www.ahrq.gov/downloads/pub/evidence/pdf/o3cardio/o3cardio.pdf.
- #27 Key Messages
- #28 References (I)
- #29 References (II)
- #30 References (III)
- #31 References (IV)
- #32 Authors