A literature review (structured evaluation of scientific literature) is the systematic search, selection, and synthesis of scientific and regulatory relevant sources addressing a clearly defined research question. In clinical development, medical device compliance, and medical writing, it serves to comprehensibly present the current state of knowledge, identify evidence gaps, and justify decisions. Depending on the objective, a review can be conducted as a narrative summary, a systematic review, or as part of a clinical evaluation under the MDR. <\/p>\n
In projects, literature reviews are used, among other things, for planning clinical trials (endpoint selection, comparator therapies, expected effect sizes), for risk assessments, for writing clinical study reports, and for regulatory dossiers. For medical devices, they are a central component of clinical evaluation and post-market clinical follow-up, as external clinical data can support the safety and performance of the product. A review thus often forms the bridge between scientific literature, internal data, and regulatory requirements. <\/p>\n
In practice, the quality of the review determines whether assessment bodies accept the argumentation as complete and reproducible. Unclear search strategies or selective selection can be considered bias and often lead to queries during the review process. <\/p>\n
A robust literature review begins with a precise research question and clear inclusion and exclusion criteria (population, intervention, comparison, endpoints, study types, timeframes, languages). Based on this, a search strategy is defined for databases (e.g., PubMed\/MEDLINE, Embase) and grey literature (guidelines, authority reports, registry data). It is important that search strings, search dates, filters, and hit counts are documented so that an independent person can reproduce the process. <\/p>\n
To select publications, two independent reviewers are often employed to reduce misclassifications. For extensive reviews, screening tools and structured data extraction are helpful. For regulated documents, an audit trail mindset is also important: Why was a source excluded, and which version was used? <\/p>\n
In addition to the content summary, critical evaluation of the evidence is essential. This includes questions such as: Are the studies randomized and blinded? How high is the risk of selection or publication bias? Are endpoints clinically relevant or surrogate? How consistent are the results across studies? Standardized assessment frameworks are used for this in systematic reviews, while narrative reviews should at least contain transparent chains of argumentation. <\/p>\n
Typical pitfalls include duplicate publications of the same study, incomplete reporting, or overlooking unpublished registry data. Therefore, cross-referencing with study registries and regulatory public assessment reports is often useful. <\/p>\n
Another practical aspect is data extraction: even with just a few dozen sources, a standardized extraction table is worthwhile, recording population, study design, endpoints, follow-up duration, relevant safety events, and key effect sizes. This makes it transparent why certain statements are made and what uncertainties exist. For regulatory documents, it is also important that citations can be clearly traced back to the original source. <\/p>\n
If a review serves as input for a study protocol, it should explicitly demonstrate how literature findings were translated into design decisions \u2013 for example, in the choice of a comparator, assumptions about event rates, or the definition of clinically relevant effect sizes. This increases internal traceability and reduces the risk of later protocol amendments. <\/p>\n
In day-to-day CRO operations, timeliness also plays a role: for ongoing programs, reviews are often maintained as “living” documents that are updated at defined intervals. In such cases, versioning, search updates, and the handling of newly identified evidence must be clearly described to ensure the review remains reproducible. <\/p>\n
In the context of MDR 2017\/745, a systematic literature search is expected as part of the clinical evaluation. Manufacturers must demonstrate that relevant clinical data have been identified and appropriately evaluated, including whether the literature concerns their own product or similar products. In the pharmaceutical sector, literature evaluations are also established in dossiers and risk management documents, for example, to assess known risks or classify safety signals. <\/p>\n
For clinical trials under Regulation (EU) No 536\/2014 and within the framework of ICH E6(R3): literature searches rarely replace the need for controlled study data, but they can underpin the rationale, justify endpoints, and support the selection of safety parameters. In medical writing processes, consistency is also crucial: citations, statements, and conclusions must align with the data status and be properly referenced. <\/p>\n
A clear structure has proven effective: search strategy and flow (identified, screened, included), tabular extraction of core data, and a synthesis that discusses strengths, weaknesses, and relevance to the research question. If quantitative syntheses are not appropriate, the reasons should be justified (heterogeneity, missing data, different endpoints). For sponsors, it is helpful to determine early on which statements in the dossier are claim-relevant and therefore require particularly stringent evidence. <\/p>\n
FAQ<\/strong><\/p>\n What is the difference between a systematic and a narrative review?<\/strong><\/p>\n A systematic review follows a predefined search and selection methodology and documents it transparently. A narrative review summarizes literature more broadly but is more susceptible to selection bias if the methodology is not disclosed. <\/p>\n Which sources count as grey literature?<\/strong><\/p>\n This includes guidelines, authority reports, HTA documents, conference contributions, or study registries. They are important because not all relevant results are published in journals. <\/p>\n How detailed must the search strategy be documented?<\/strong><\/p>\n At a minimum, search terms, databases, search date, filters, and hit counts should be specified. In regulated documents, a comprehensible justification for inclusions and exclusions is also required. <\/p>\n Regulatory References:<\/strong> Regulation (EU) 2017\/745 (MDR), Regulation (EU) No 536\/2014 (Clinical Trials Regulation), ICH E6(R3) Guideline for Good Clinical Practice.<\/p>\n","protected":false},"excerpt":{"rendered":" A literature review (structured evaluation of scientific literature) is the systematic search, selection, and synthesis of scientific and regulatory relevant sources addressing a clearly defined research question. In clinical development, medical device compliance, and medical writing, it serves to comprehensibly present the current state of knowledge, identify evidence gaps, and justify decisions. Depending on the […]<\/p>\n","protected":false},"author":10,"featured_media":0,"parent":0,"template":"","meta":{"_acf_changed":false,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"glossary-cat":[],"class_list":["post-6783","glossary","type-glossary","status-publish","hentry"],"acf":[],"related_terms":"","external_url":"","internal_reference_id":"","_links":{"self":[{"href":"https:\/\/mediconomics.com\/en\/wp-json\/wp\/v2\/glossary\/6783","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/mediconomics.com\/en\/wp-json\/wp\/v2\/glossary"}],"about":[{"href":"https:\/\/mediconomics.com\/en\/wp-json\/wp\/v2\/types\/glossary"}],"author":[{"embeddable":true,"href":"https:\/\/mediconomics.com\/en\/wp-json\/wp\/v2\/users\/10"}],"version-history":[{"count":0,"href":"https:\/\/mediconomics.com\/en\/wp-json\/wp\/v2\/glossary\/6783\/revisions"}],"wp:attachment":[{"href":"https:\/\/mediconomics.com\/en\/wp-json\/wp\/v2\/media?parent=6783"}],"wp:term":[{"taxonomy":"glossary-cat","embeddable":true,"href":"https:\/\/mediconomics.com\/en\/wp-json\/wp\/v2\/glossary-cat?post=6783"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}