What’s in a Name? Systematic and Non-Systematic Literature Reviews, and Why the Distinction Matters

Rachel Huelin Director and Research Scientist, Meta Research Ike Iheanacho, MBBS Director and Research Scientist, Meta Research Krista Payne, MEd Executive Director, Evidence Strategy Solutions Karen Sandman, PhD U.S. Practice Lead, Payer Communications

At Evidera, we routinely have conversations with external such as “systematic literature review.” At a minimum, colleagues who would like our help in gathering publicly this range of understanding can result in confusion and available information to answer research questions, unclear expectations and, in some cases, it could even inform business decisions, support submissions to impact the success of the literature review as a stand- external authorities, or provide inputs into other research alone project or the success of associated downstream efforts such as economic analyses. The scientific literature activities such as qualitative or quantitative research or is a rich source of information that can guide healthcare external submissions. research and decision making, and a literature review is often a cost-effective and time-efficient approach to The accompanying table outlines some common types gather evidence. of literature and informational reviews, their typical methodology and objectives, and how they might be In our experience, different people may have quite used to inform other efforts. different types of studies in mind when they use terms

Type of Methodologies Objectives and Definition Review Employed Typical Applications A scientific study designed Follow established guidelines Considered the optimal to address a specific research set down by authorities such as type of literature review for question by comprehensively the Institute of Medicine and the publication (particularly in collecting all the information Preferred Reporting Items for higher tier medical journals) available on a topic that is Systematic Reviews and Meta- and conference presentations. defined at the outset by absolute Analyses (PRISMA) Statement.1 inclusion and exclusion criteria. Required for many payer Typically involves searching multiple, submissions and other types Considered the “gold standard” predefined electronic databases and of formal documentation. for evidence assessment. grey literature sources. Findings can be used to conduct Systematic When appropriate, this gold- Selection criteria define topic areas a classical meta-analysis or network literature standard approach may be adapted as well as characteristics such as meta-analysis (indirect/mixed review to produce a more manageable publication dates, the languages treatment comparison); may also (SLR) scope while retaining elements in which articles are published, be used to provide inputs for that ensure rigor and minimize bias and whether articles describe only economic models. in the identification of relevant human subjects. literature (e.g., use of a protocol, May be qualitative, e.g., to assess systematic search, and screening). The search and screening protocol burden of illness; epidemiology; Such an approach is sometimes is reported in the methods section clinical, economic, and humanistic called a structured review. of the report, along with a PRISMA outcomes; or treatment patterns. diagram, a flowchart showing This information can be used to the number of — and reasons guide evidence generation strategies for — articles being identified and and clinical development programs. excluded at each step of the process.

EVIDERA.COM Type of Methodologies Objectives and Definition Review Employed Typical Applications A non-systematic literature review Largely based on a knowledgeable Guide strategy and support that is meant to be an informative, selection of current, high-quality evidence-based decision making rather than all-encompassing, review articles on the topic of interest. within a product team. of the literature on a topic. Targeted May or may not follow a Help to identify trends and better literature Generally takes an in-depth but not predefined protocol. understand the current state of review systematic approach to a specific a field. research question. Also called Generally the preferred approach a “focused for populating disease and treatment background sections of a dossier or literature for identifying model inputs. review” Can be published, but generally appears in lower tier journals than systematic literature reviews. A comprehensive review of health Generally, a defined list of HTA Understand past payer technology assessments (HTAs) sources and sites are searched using decisions and feedback on regarding a medical intervention, a fairly broad set of search terms an area of interest. product, or therapeutic area. relating to the subject matter. HTA Inform evidence generation and review The resulting HTA reports are clinical development plans. screened for relevance. Identify potential payer concerns and proactively develop evidence- based responses. A rapid review of key topics of Integrates evidence from literature, May be used to inform decision Landscape interest relating to a therapeutic pricing and reimbursement sources, making on in-licensing opportunities area, including but not limited to HTAs, and other public sources and, or new development programs. review or burden, unmet need, competitive in some cases, proprietary sources disease landscape, payer perspectives, such as payer and provider research, Provide background evidence area regulatory considerations, and and advisory boards. for a preliminary framework strategy data gaps. value proposition, value report demonstration plan, and/or payer research program. An analysis of topic areas in which Therapeutic area experts typically Anticipate potential concerns evidence is sparse or nonexistent, analyze outputs of a targeted or that may arise from payers. Gap often conducted as part of a systematic literature review and analysis literature review and/or evidence identify gaps, and then conduct Inform an evidence generation generation plan. follow-up searching to confirm the plan. lack of evidence. What type of review would best suit your needs? When considering what type of review would best meet your research and business objectives, ask yourself and your colleagues:

• What is the evidence need, and which specific • Are there established guidelines governing how this research questions do we want to answer? type of review should be conducted?

• How much time and resources can we commit to • Do we intend to publish our findings? this effort? • Would this review be useful to other work streams • How quickly do we need the research findings to within our organization? If so, do their requirements be available? differ from ours?

• Who are the internal and/or external audiences for this review, and do they have specific expectations or stipulations about how it will be conducted? For more information, please contact [email protected] or [email protected].

REFERENCES 1 Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, Shekelle P, Steward LA, and PRISMA-P Group. Preferred Reporting Items for Systematic Review and Meta-analysis Protocols (PRISMA-P) 2015 Statement. Syst Rev. 2015 Jan 1; 4:1.

THE EVIDENCE FORUM May 2015