Methodological Guidance for a Quality Review Article

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Readers of The Gerontologist are familiar with population changes and projections that have spurred a surge in gerontological research across disciplines. This proliferation of research increases the importance of high-quality review and synthesis for moving research forward and informing policy and practice. We have therefore witnessed an increased number of systematic review publications in the field of gerontology (Shenkin, Harrison, Wilkinson, Dodds, & Ioannidis, 2017). In 2015, The Gerontologist began accepting review articles and as of August 2018, The Gerontologist has received more than 250 review submissions. We are anticipating that this figure will double by the end of 2019. In response to the high number of review submissions and the need for rigorous evaluation, Patricia C. Heyn, PhD, FGSA, joined The Gerontologist’s editorial leadership team in 2017 as the Associate Editor for review articles. Dr. Heyn, an expert in the synthesis and systematic review methodologies, has led efforts to redesign The Gerontologist “Review Articles” section by formulating a clear set of guidelines and instructions for authors interested in submitting review articles to the journal. The goal of the section is to produce and disseminate the best evidence available in the field of gerontology. The purpose of this editorial is to provide to The Gerontologist readers resources and guidance to prepare a high-quality review report that requires a thorough and updated search of the literature. Contemporary utilization of systematic synthesis methodology is driven by the rapidly increasing number of scientific publications in the last decades (Rapple, 2011). Most of the review articles that use synthesis methods (e.g., scoping review, systematic review, and meta-analysis) have the goal to provide state-of-the-art knowledge on a topic by summarizing data from primary published studies and attempting to aggregate and reconcile the scientific results from the individual studies. The synthesis procedures should be unbiased, clearly organized, and reproducible (Ketcham & Crawford, 2007). Although scientists are usually recognized for their contribution in primary research, a timely and properly conducted literature review can lead to best practices and improve the quality of future research (Hampton & Parker, 2011). However, for a review article to be valuable, it needs to be designed and assembled in a rigorous, reproducible, and systematic fashion (Higgins, 2008; Mulrow, 1987) as originally noted and developed by the Cochrane Collaboration (1972), an international network of health care professionals. The popularity of published peer-reviewed articles can lead to confusion about best practice for synthesizing the evidence that will lead to appropriate rigor and transparency (CEBM, 2001). A well-designed and organized review report should include five important and distinct phases, as described in Figure 1. Evidence-based practice guided by transparency and rigor. A systematic literature review that is based on synthesis methodology includes a protocol and results from all available studies related to the topic of interest, and provides a thorough analysis of the results, strengths, and weaknesses of the collated studies. It addresses a focused, clearly formulated question and uses systematic and explicit methods. Narrative Reviews are often just called Reviews or Literature Review and they are usually opinion review based on selective evidence from the literature. Narrative review is based on informal process in which studies are selected and examined in an undefined manner. They do not qualify as adequate evidence to answer clinical questions (Davidson & Iles, 2013). Rather than answering a specific clinical question, they provide a broad and shallow overview of the research landscape of a given topic and so may be useful for background information. Narrative reviews usually lack systematic search protocols or explicit criteria for selecting and appraising evidence and are therefore very prone to bias (Davidson & Iles, 2013). Synthesis-based reviews, but not narrative reviews, will be considered for publication in The Gerontologist. The main objectives for undertaking a synthesis review study are to minimize bias and maximize data interpretation by combining and collating similar data from all the relevant and available evidence. Therefore, to avoid misleading or erroneous premises, a number of key methodological conditions need to be satisfied. Since the implementation of the QUOROM (Quality Of Reporting Of Meta-analysis) statement, a reporting guideline published in 1999, there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of reviews, and these are shown in Table 1. Of these, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement provides excellent direction for authors developing research reviews. The PRISMA statement (Liberati et al., 2009) consists of a 27-item checklist and a flow diagram: http://prisma-statement.org/PRISMAStatement/Checklist. PRISMA was designed to assure transparent reporting on a review and provides a methodological framework to help prospective authors of review studies to complete a high-level review to adequately represent their specialties. Review Article Reporting Standards Note: EQUATOR = Enhancing the Quality and Transparency Of health Research; CONSORT = Consolidated Standards of Reporting Trials; STROBE = Strengthening the Reporting of Observational Studies in Epidemiology; PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses; MECIR = Methodological Expectations of Cochrane Intervention Reviews; IOM = Institutes of Medicine Review Article Reporting Standards Note: EQUATOR = Enhancing the Quality and Transparency Of health Research; CONSORT = Consolidated Standards of Reporting Trials; STROBE = Strengthening the Reporting of Observational Studies in Epidemiology; PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses; MECIR = Methodological Expectations of Cochrane Intervention Reviews; IOM = Institutes of Medicine In addition to the methodologies shown in Table 1, many journals have developed standards for scientific reporting that emphasize transparency and rigor. Such standards have been endorsed by international groups such as the International Committee of Medical Journal Editors (ICMJE) and the Committee on Publication Ethics (COPE). The ICMJE has published general standards for crafting scientific articles, the “Uniform Requirements for Manuscripts Submitted to Biomedical Journals: Writing and Editing for Biomedical Publication” (ICMJE, 2009). These guidelines include suggestions for manuscript preparation and guidelines for ethical matters related to publishing, and these standards apply to review papers as much as to primary research papers. Many synthesis methods, variants of the classical systematic review method, have emerged in the recent years. Table 2 shows the most common methods currently in use, those most likely to be acceptable for The Gerontologist. Determining the unique contribution of each of these synthesis methods and selecting the most suitable method can be challenging. The various synthesis types and methodologies rely on different aspects of the available literature such as the current state of the knowledge on a specific topic, how narrow or broad the synthesis will be, as well as the quality of the current evidence. For detailed information about the different types of review methodology, Grant and Booth (2009) provide a comprehensive summary of the most common types of review methods. Here we summarize the features of the two most popular types. Common Variation in Evidence Synthesis Methodology: Review Article Type Note: PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses Common Variation in Evidence Synthesis Methodology: Review Article Type Note: PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses Systematic reviews (SRs) and meta-analyses (MAs) have become more and more popular (Moher, Cook, Eastwood, Olkin, Rennie, & Stroup, 1999), and can offer the highest grade of evidence (Figure 2) for driving the decision-making process for consumers, clinicians, funders, payers, researchers, and policy-makers. Both SRs and MAs have well-established standardized methods for the conduct and reporting, codified in the Institute of Medicine (IOM) standards and PRISMA reporting guidelines. SRs are the most common review approach. They have the goal to appraise, synthesize, and summarize current knowledge, and to reconcile conflicting scientific results from individual primary studies. They use comprehensive, objective, explicit, and transparent methods, allowing the reader to follow how conclusions were reached, duplicate the study, and to generalize the findings (Ketcham & Crawford, 2007). SRs may indicate that further primary research is needed in areas where no evidence exists or that current evidence is inconclusive. They are essential knowledge translation tools for researchers, practitioners, and policy-makers who are especially struggling to keep up with the accumulating, ever-increasing, body of evidence (Hampton & Parker, 2011). A well-designed SR may or may not include an MA that includes statistical procedures and data (i.e., effect sizes) to reflect a best estimate of the accumulated evidence. The MA method requires the studies to have the same outcome measure (Ottenbacher, Heyn, & Abreu, 2017). Reviews based on synthesis methodology, such as SRs and MAs, may be undertaken to confirm whether current practice is based on evidence (or not) and to address any uncertainty or variation in practice that may be occurring. They are also helpful in identifying where evidence is scarce or misleading and can help categorize future research. Most importantly, they are used to produce statements to guide decision making. Levels of evidence. The figure represents the hierarchy of evidence provided by the National Health and Medical Research Council (NHMRC, 2009). Many published reviews are founded upon a selective sample of elementary research and/or rely on expert opinion lacking the desirable unbiased and systematic method approach. Thus, they are more akin to narrative reviews (Bhandari, Morrow, Kulkarni, & Tornetta, 2001; McKibbon, 1998; Sacks, Reitman, Pagano, & Kupelnick, 1996). The inclusion of poor-quality studies without substantial appraisal can also mislead the scientific field (ICMJE, 2009). The overall interpretation of findings should be considered with respect to the strength of the best available evidence to date, the methodological quality and appraisal of the studies, consistency across studies, applicability to practice, implementation, and generalizability. Prior to deciding what type of review method to conduct, authors should be knowledgeable about the different review typologies and synthesis methods to adequately address the breadth and depth of the research that will be undertaken. Despite the type of synthesis methodology that the review article is presenting, The Gerontologist welcomes review articles that use synthesis methods (such as scoping/systematic review, meta-analysis) that are guided by the best scientific reporting standards according to the IOM, PRISMA, and Cochrane. Therefore, authors are expected to clearly define the review typology (i.e., meta-analysis or scoping review or systematic review) and the rationale for the selected methodology in the article. The PRISMA flow chart and checklist should be included with the submission. In addition, literature appraisal and evidence quality evaluation methods are likewise important (Higgins, 2008; Ottenbacher, Heyn, & Abreu, 2017). Given the significance of transparency in reporting review articles, authors should report the study protocol and synthesis results by using supplementary tables such as the “Studies Characteristics” table (i.e., publication year, study design type, sample size, age, and diagnosis), and any other pertinent information about the review protocol such as the search terms, search dates, and the databases that were used to obtain the included studies and list the exclusion reasons. The search date should be up-to-date when submitting the review article to the journal. Authors should consider including a librarian, as a function of the expert review team, to comprehensively design, execute, and update the search, compile the citations, create a search strategy appendix, and compose the appropriate components of the methods section. Because of the limited page budget allotted for print publications and the tendency for review articles to be lengthy, The Gerontologist publish review articles online only (i.e., the article title would appear in the Table of Contents for print issues of the journal, but the article itself would appear online only). Review articles will go through the same peer review and editing processes that any other published articles in The Gerontologist undergo. Articles will receive a DOI, be searchable, and will be available electronically. Review article submissions are allowed up to 8,000 words in length. In closing, The Gerontologist publishes research and analysis on applied social issues with the aim to inform the broader community of disciplines and professions in understanding the aging process and providing care to older adults. The inauguration and expansion of the “Review Article” section have contributed greatly to the field, having resulted in the publication of numerous original review articles since 2015. We have no doubts that our review articles will influence positively the future of gerontological research and practice and that the gerontological community will continue to help us in building the best evidence in the field.