Narrative Reviews in Veterinary Medicine: When and How to Write Them

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Narrative reviews are scientifically appropriate for broad, exploratory, or conceptual questions in veterinary medicine, particularly when integrating heterogeneous evidence from diverse study types (e.g., in vitro, animal, clinical) or explaining complex biological mechanisms, rather than answering narrowly defined clinical questions best suited for systematic reviews.
• A critical failure mode of narrative reviews is selection bias, which can be mitigated by transparently documenting the databases searched, search terms used, and date ranges, even if the search is not exhaustive, to allow readers to assess the breadth of the literature considered.
• Narrative reviews must engage in critical synthesis, assessing the methodological quality of primary studies (e.g., study design, sample size, species relevance, risk of bias) and explicitly acknowledging uncertainty, contradictions, and gaps in the evidence, rather than merely summarizing findings.
• The structure of a narrative review should follow the logic of the question, typically organizing literature thematically or by proposed mechanism of action (e.g., neural blockade, systemic absorption for erector spinae plane blocks), and should clearly distinguish between biological plausibility and established clinical efficacy.
• Authors must explicitly address species differences when generalizing across veterinary medicine, noting where findings are species-specific (e.g., metabolic pathways, drug disposition) and discussing the biological basis for cautious extrapolation, consulting resources like the WOAH Terrestrial Animal Health Code for production animal contexts.
• Transparency in reporting is paramount; authors should document their search strategy, inclusion/exclusion criteria, and limitations, and consult guidelines such as ARRIVE for animal research reporting to ensure clarity and reproducibility, even in a non-protocolized format.

The narrative review remains a common and valuable scholarly format in veterinary medicine, yet its methodological foundations are frequently misunderstood. This article explains what distinguishes a narrative review from a systematic review, defines the situations in which a narrative approach is scientifically appropriate, and provides a practical framework for planning, searching, writing, and publishing a rigorous narrative review. It is written for veterinary researchers, graduate students, and clinicians who intend to produce a review article but are uncertain about the procedural requirements and scholarly standards expected of the format.

The central question this article answers is practical: when should you choose a narrative review over a systematic review, and how do you execute the narrative format so that it withstands editorial and peer scrutiny? The guidance applies across species and disciplines, from companion animal medicine to production animal health and wildlife studies. Meta-analysis is excluded from this discussion, as are the quantitative pooling methods associated with it. The focus rests on the narrative review as a distinct, defensible scholarly product.

A narrative review synthesises published literature using a structured but non-protocolised approach. It differs from a systematic review in its objectives, methods, and evidentiary claims. A systematic review answers a narrowly defined clinical question through exhaustive, reproducible search strategies and explicit inclusion criteria, often followed by meta-analysis. A narrative review, by contrast, addresses broader questions, integrates diverse study types, and interprets the literature through the author's analytical lens. Both formats have legitimate roles, and the choice between them should follow from the question being asked, not from convention or convenience.

At a Glance

Defining the Narrative Review

The narrative review is best understood as an interpretive synthesis. The author selects, organizes, and interprets primary studies to construct an argument about the state of knowledge in a defined area. This format is well suited to topics where the evidence base is heterogeneous, where mechanisms matter more than pooled effect sizes, or where the literature spans multiple disciplines. The narrative review of bacteriophage therapy for bacterial infections illustrates this function: the authors integrated in vitro, animal, and early clinical data to assess whether phages represent a rational response to antimicrobial resistance, concluding that current knowledge is insufficient to support routine clinical use Advantages and Limitations of Bacteriophages for the Treatment of Bacterial Infections.

The narrative format also accommodates topics where the primary literature is methodologically diverse. A review of the biological mechanisms linking periodontitis and diabetes, for example, drew on molecular microbiome studies, clinical investigations, and animal experiments to construct a coherent model of bidirectional inflammatory pathways An update on the evidence for pathogenic mechanisms that may link periodontitis and diabetes. A systematic review with meta-analysis could not have integrated these disparate study designs into a single quantitative estimate, yet the narrative synthesis produced clinically useful conclusions about shared inflammatory mediators and the effects of periodontal treatment on systemic markers.

Narrative Versus Systematic Approaches

The decision between narrative and systematic formats rests on the nature of the question. Systematic reviews are the appropriate instrument when the question is discrete, the literature is sufficiently homogeneous, and a quantitative or structured qualitative answer is achievable. Narrative reviews are preferable when the question is conceptual, the evidence base is fragmented, or the goal is to propose a new synthesis of existing knowledge.

Consider the question of whether a specific analgesic technique provides effective pain relief. A systematic review with meta-analysis would be the appropriate design, provided sufficient randomised trials exist. But the question of how that technique produces analgesia, which mechanisms are plausible, and which anatomical structures are involved is a mechanistic question that resists quantitative pooling. The narrative review of erector spinae plane block mechanisms illustrates this distinction: the authors integrated clinical observations, cadaveric injection studies, animal experiments, and laboratory data to evaluate competing mechanistic hypotheses, concluding that direct local anesthetic spread to neural structures is the most probable primary mechanism Mechanisms of action of the erector spinae plane (ESP) block: a narrative review. This synthesis would have been impossible within a systematic review framework.

The Scientific Role of Narrative Synthesis

Narrative reviews perform scientific work that systematic reviews cannot. They generate hypotheses, expose contradictions, and reframe problems. A narrative review of bone graft biomaterials asked why so few substitutes reach clinical availability despite an extensive laboratory literature, identifying the gap between experimental innovation and clinical translation as a central problem in the field Bone grafts: which is the ideal biomaterial?. This type of critical appraisal, which questions the direction of a research field instead of the magnitude of a treatment effect, is a legitimate and valuable scholarly contribution.

The narrative review also serves an integrative function across species and disciplines. Veterinary questions frequently draw on literature from human medicine, laboratory animal science, and multiple veterinary species. A narrative format permits the author to weigh evidence across these domains and to explain how findings from one context inform another. The review of Western diet effects on metabolism, for instance, integrated nutritional science, immunology, microbiology, and clinical medicine to describe a dietary pattern's systemic consequences Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review. Veterinary readers can adapt this integrative model to questions of companion animal nutrition, production animal feeding systems, and comparative metabolic disease.

Limitations and Failure Modes

The narrative review has well-documented weaknesses, and the author who ignores them produces an indefensible manuscript. Selection bias is the most serious risk. Without a documented search strategy, the reader cannot judge whether the included literature represents the field or merely the author's prior reading. Confirmation bias operates silently when an author unconsciously selects studies that support a preferred conclusion. The remedy is procedural transparency: state the databases searched, the date range covered, the search terms used, and the inclusion criteria applied, even when the search is not exhaustive.

A second failure mode is the absence of critical appraisal. A narrative review that reports study findings without assessing their methodological quality misleads the reader. The author should comment on study design, sample size, species relevance, and risk of bias for the key studies that support major claims. Where the evidence is weak or contradictory, the review should say so explicitly.

A third failure mode is the substitution of assertion for synthesis. A review that merely lists what each study found, without explaining how the findings relate to one another, is an annotated bibliography instead of a narrative review. The scholarly value lies in the interpretation: the connections drawn, the contradictions resolved, and the gaps identified.

Reporting Standards and Transparency

Although no single reporting guideline governs narrative reviews, the EQUATOR Network maintains a comprehensive library of reporting standards for health research, and authors should consult it to identify any guideline applicable to their specific review type EQUATOR Network reporting guidelines. For veterinary reviews that include animal studies, the ARRIVE guidelines provide a useful reference for the minimum information required to evaluate the primary studies being synthesised ARRIVE guidelines for reporting animal research. These resources do not dictate the structure of a narrative review, but they inform the standards of transparency that reviewers and editors will expect.

The author should document the search process in sufficient detail that a reader could reproduce the search and verify that the literature base is appropriate. This documentation typically appears in a methods paragraph or section, even in a narrative review. The description should include the databases searched, the date of the search, the search terms or MeSH headings used, and any language or date restrictions applied. The narrative review of bacteriophage therapy provides a model: the authors searched PubMed from January 2008 to December 2018, restricted inclusion to English-language publications providing evidence-based data, and described this process in their methods Advantages and Limitations of Bacteriophages for the Treatment of Bacterial Infections.

Planning the Narrative Review: Defining the Question and Scope

A narrative review begins with a question, but the question must be framed with enough specificity to guide a meaningful search and synthesis. A question such as "what is the evidence for pain management in dogs" is unworkable. A better formulation narrows the population, intervention, comparison, and outcome of interest, even if the review will not apply the full PICO framework used in systematic reviews. For example, "what is the evidence for locoregional analgesic techniques in canine pelvic limb surgery, and how do reported outcomes compare across techniques" gives the reviewer a boundary for literature selection and a structure for synthesis.

The scope decision should also address the intended audience and purpose. A review written for general practitioners to support clinical decisions will emphasize practical comparisons and gaps in the evidence. A review written for researchers to justify a new study will emphasize mechanistic uncertainty and methodological limitations. The same literature can support both, but the selection and weighting of sources will differ. State the intended audience and purpose in the introduction so that readers can judge whether the review serves their needs.

The search strategy for a narrative review does not need the exhaustive, protocol-driven approach of a systematic review, but it should be transparent and reproducible enough for a reader to understand what was found and what was missed. The authors of a narrative review on bacteriophage therapy described searching PubMed from January 2008 to December 2018 with defined keywords and then applying inclusion criteria for English language and evidence-based data advantages and limitations of bacteriophages for the treatment of bacterial infections. This level of detail, while less rigorous than a PRISMA-compliant search, allows the reader to assess the currency and breadth of the evidence base. A similar approach, using MeSH terms, keywords, and title words with a defined publication window, was used in a narrative review of the biological association between periodontitis and diabetes update on evidence for pathogenic mechanisms linking periodontitis and diabetes.

Document the search decisions before writing. Record the databases searched, the date of the search, the terms used, and the inclusion and exclusion criteria. This documentation does not need to be published in full, but it should be available for peer reviewers or editors who ask how the literature was identified. The EQUATOR Network reporting guidelines library provides a catalogue of reporting standards for many study designs, and while no single guideline governs narrative reviews, consulting the library helps authors identify which elements of transparency are expected in their target journal.

Structuring the Narrative Review

The structure of a narrative review should follow the logic of the question, not the chronology of the literature search. A common and effective structure moves from background and definitions, to the current state of evidence organized by theme or mechanism, to a synthesis of what is known and unknown, and finally to implications for practice or research.

The thematic organization is the most important structural decision. Group the literature by conceptual theme instead of by study type or chronology. A review of the erector spinae plane block organized the evidence by proposed mechanism of action, including neural blockade, systemic absorption, immunomodulation, and fascial mechanosensory effects, before concluding which mechanism was best supported mechanisms of action of the erector spinae plane block. This structure allows the reader to follow the reasoning instead of a list of studies.

Within each theme, present the evidence in a logical order. Start with the strongest or most direct evidence, then address conflicting findings, then note gaps. Use tables to summarize study characteriztics, reported outcomes, and methodological limitations. Tables are particularly useful in narrative reviews because they allow the author to present a large volume of information without interrupting the prose.

Critical Synthesis and Interpretation

The value of a narrative review depends on the quality of the synthesis, not the number of citations. A synthesis should do more than summarize each study in sequence. It should identify patterns across studies, explain contradictions, and propose interpretations that are not apparent from any single source.

When studies conflict, examine the sources of disagreement. Differences in species, breed, age, disease severity, outcome measures, and study design can all explain divergent results. A review of bone graft biomaterials noted that laboratory studies tend to focus on advanced production methods and novel biomaterial features, but only a handful of substitutes reach clinical availability, and the authors asked why this gap exists bone grafts which is the ideal biomaterial. This type of question, which interrogates the relationship between the evidence base and clinical reality, is a hallmark of a useful narrative review.

Acknowledge uncertainty explicitly. If the evidence is limited to small studies, or if findings are inconsistent, say so and explain what additional evidence would be needed to resolve the uncertainty. The review of the Western diet and its metabolic effects applied exclusion criteria for irrelevant topics and unpublished studies, but the authors still noted that the evidence base spans diverse populations and outcomes, which limits the precision of any conclusions global impacts of western diet and its effects on metabolism and health. This honest assessment of the evidence base is more useful to readers than a confident but unsupported conclusion.

Practical Writing and Documentation

Write the review in stages. Draft the thematic sections first, then write the introduction and conclusion after the synthesis is complete. This order ensures that the introduction accurately reflects the content and that the conclusion follows from the evidence presented.

Use tables and figures to present comparative data, but do not duplicate in the text what is already clear from a table. Each table should have a clear purpose and a title that describes its content. The ARRIVE guidelines for reporting animal research emphasize the importance of clear reporting of methods and results, and while these guidelines are designed for primary research, their principles of transparency and completeness apply to the way a review describes the studies it cites.

Species and production system differences should be stated explicitly. A review of pain management that draws on studies in dogs, cats, and horses must note where findings are species-specific and where they can be generalized. Similarly, a review of antimicrobial use must distinguish between companion animal, food animal, and exotic species contexts, and must acknowledge that regulatory frameworks differ between regions. The WOAH terrestrial animal health code provides international standards for animal health and disease control, and authors writing about infectious disease or trade-related topics should consult these standards to ensure their review reflects current international expectations.

The final manuscript should include a description of the search strategy, the inclusion criteria, and the limitations of the review. This information allows readers to judge the scope of the review and to identify literature that may have been missed. The MSD Veterinary Manual and AVMA practice resources can serve as starting points for verifying clinical facts and professional standards, but the review itself should cite primary literature for specific claims.

Recognized Complications and Early Detection

The most common failure mode in a narrative review is the loss of a defensible boundary between synthesis and advocacy. This manifests as selective citation, where the author includes sources that support a preferred position and omits those that do not. Early detection requires a simple audit. For each major claim, ask whether the cited evidence represents the full range of published findings or only a subset. A second failure mode is the absence of a clear search strategy. Even when a narrative review does not require the exhaustive search of a systematic review, the method should be stated. The review of bacteriophage therapy by Principi et al. illustrates this point, as the authors explicitly described their PubMed search terms and inclusion criteria, which allowed readers to gauge the breadth of the evidence considered Advantages and Limitations of Bacteriophages for the Treatment of Bacterial Infections. A review that omits this information cannot be distinguished from an opinion piece.

A third complication is the conflation of biological plausibility with clinical efficacy. Narrative reviews often assemble mechanistic studies and extrapolate to clinical recommendations. The review of erector spinae plane block mechanisms demonstrates the correct approach, weighing evidence from cadaveric, animal, and clinical studies before concluding that a direct neural effect is most probable Mechanisms of action of the erector spinae plane (ESP) block: a narrative review. The authors explicitly ranked the strength of each proposed mechanism. When a narrative review fails to rank evidence by strength, it risks presenting a speculative mechanism as an established fact.

Common Errors and Corrective Action

Less experienced authors frequently mistake a narrative review for an annotated bibliography. They summarize each paper in sequence without developing an argument that connects the studies. The corrective action is to organize the review by theme or question, not by author or chronology. Each paragraph should advance a claim that is supported by multiple sources, and the author should explicitly state how the sources relate to one another, whether they agree, conflict, or address different aspects of the question.

A second common error is the use of imprecise language to describe evidence strength. Phrases such as "studies show" or "research indicates" obscure the difference between a randomised trial and a case series. The corrective action is to name the study design when describing a finding. For example, the review of periodontitis and diabetes distinguished between small-scale molecular microbiome studies, clinical studies, and animal studies when summarizing the evidence for inflammatory mediators An update on the evidence for pathogenic mechanisms that may link periodontitis and diabetes. This precision allows the reader to judge the weight of each claim independently.

A third error is the failure to acknowledge contradictory evidence. Narrative reviews are expected to synthesise, not to ignore, discordant findings. When studies conflict, the author should state the conflict explicitly and offer a reasoned explanation, such as differences in study population, outcome measures, or follow-up duration. If no explanation is possible, the author should say so.

Limitations of the Current Evidence

The evidence base in veterinary medicine is uneven. Some topics, such as the biological mechanisms linking periodontitis and diabetes, have a substantial body of mechanistic research but few studies that directly test causal relationships in clinical populations An update on the evidence for pathogenic mechanisms that may link periodontitis and diabetes. Other topics, such as the ideal bone graft biomaterial, are dominated by laboratory studies that do not translate into clinically available products Bone grafts: which is the ideal biomaterial?. A narrative review should state these gaps explicitly and avoid filling them with speculation.

Expert opinion still differs on several structural questions. One is the acceptable threshold for search comprehensiveness in a narrative review. Some editors expect a documented search strategy, while others accept an unstructured approach if the author is a recognized expert. A second area of disagreement is the role of grey literature. Some authors include conference abstracts and institutional reports, while others restrict themselves to peer-reviewed journals. The review of the Western diet, for example, explicitly excluded conference proceedings and unpublished studies, a decision that the authors stated in their methods Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review. Authors should make this decision explicit and justify it.

Referral, Consultation, and Reporting

Most narrative reviews do not require regulatory involvement. However, certain circumstances warrant escalation. If the review addresses a topic with regulatory implications, such as antimicrobial use, off-label drug use, or international trade standards, the author should consult the relevant standards. The World Organization for Animal Health publishes the Terrestrial Animal Health Code, which provides international standards for disease surveillance and trade-related control measures WOAH terrestrial animal health standards. Authors writing on these topics should verify that their recommendations do not conflict with current international standards.

Specialist consultation is appropriate when the review crosses into a field where the author lacks primary expertise. A general practitioner writing about advanced imaging should consult a veterinary radiologist. The review of periaqueductal gray neuroimaging illustrates the value of multidisciplinary input, as the authors integrated findings from pain research, psychiatry, and neuroanatomy Neuroimaging of the periaqueductal gray: state of the field. When a review touches on diagnostic test accuracy, the author should consult the reporting guidelines available through the EQUATOR Network, which maintains a comprehensive library of health research reporting standards EQUATOR Network reporting guidelines. For studies involving animal research, the ARRIVE guidelines specify the minimum information required for transparent reporting ARRIVE guidelines for reporting animal research.

Regulatory reporting is rarely required for a narrative review itself. The exception is when the review identifies a previously unrecognised adverse effect or a safety signal. In such cases, the author should report the finding to the relevant pharmacovigilance authority and should not wait for publication before doing so. The review should then describe the signal and recommend formal investigation, instead of drawing conclusions from isolated reports.

Frequently Asked Questions

How Much Time and Resources Should I Budget for a Narrative Review?

A focused narrative review typically requires three to six months of part-time work. The literature search phase alone, including screening titles and abstracts, often consumes one to two months. Budget additional time for iterative drafting, critical synthesis, and revision, which usually equals the search phase. Database access through institutional libraries may be the only direct cost, but interlibrary loan fees for full-text articles can accumulate. If you lack access to major databases, consider collaborating with a colleague at an institution with broader subscriptions. The EQUATOR Network reporting guidelines can help you structure your search documentation efficiently, reducing wasted effort.

What Should I Do When the Primary Literature Is Sparse or Contradictory?

State the contradiction explicitly and analyze its likely sources, such as differences in study populations, outcome measures, or methodological quality. Use the narrative format to propose mechanistic explanations that reconcile conflicting findings, drawing on biological plausibility instead of forcing consensus. When evidence is sparse, say so directly and describe what study designs would resolve the gap. The MSD Veterinary Manual can provide baseline physiological and pharmacological context to anchor your interpretation. Avoid the temptation to fill gaps with extrapolation from other species unless you clearly label that extrapolation as speculative.

How Do I Decide Which Studies to Include When the Literature Is Extensive?

Apply explicit inclusion and exclusion criteria before screening begins, even though a narrative review does not require exhaustive searching. Prioritize primary studies with strong internal validity, recent systematic reviews, and landmark papers that shaped the field. For clinical questions, weight randomised controlled trials and prospective cohort studies over case series. When selecting among many similar studies, prefer those with larger sample sizes, longer follow-up, and clinically relevant outcomes. Document your selection rationale in the methods paragraph so readers can judge potential bias. The ARRIVE guidelines for animal research reporting can help you assess the reporting quality of preclinical studies you are considering.

Can I Write a Narrative Review Without Access to a University Library?

Yes, but with limitations. PubMed Central, Google Scholar, and open-access journal archives provide substantial coverage of veterinary and biomedical literature. Many publishers offer free access to older articles or allow authors to deposit accepted manuscripts in repositories. Contact corresponding authors directly for reprints, a practice that is common and usually successful. If you cannot verify the full text of a study, do not cite it from abstract alone. The AVMA professional practice resources include guidance on evidence-based medicine that can help you prioritize which sources matter most when full-text access is limited.

How Should I Handle Species Differences When Generalizing Across Veterinary Medicine?

Treat species differences as a central analytical theme, not a caveat. Structure your synthesis around mechanisms that are conserved across species, then address where species-specific physiology alters clinical application. For example, metabolic pathways, drug disposition, and pain processing differ substantially between ruminants, horses, and companion animals. When evidence comes from a single species, state that explicitly and discuss the biological basis for cautious extrapolation. International standards such as the WOAH terrestrial animal health code can provide context for production animal considerations, while companion animal extrapolation requires more caution given the limited comparative pharmacology data.

What Records Should I Keep During the Review Process?

Maintain a search log with database names, search dates, and the exact terms used. Keep a screening spreadsheet listing each identified record, the decision to include or exclude, and the reason for exclusion. Save PDFs in a structured folder system organized by theme. Track your synthesis notes separately from your reference list, noting where each source supports or contradicts your emerging argument. These records serve two purposes: they allow you to verify claims during revision, and they provide material for the methods paragraph that reviewers will expect. The EQUATOR Network reporting guidelines list the minimum reporting elements that your documentation should support.

Related Clinical & Scientific Guides

• Conducting Systematic Reviews of Veterinary Diagnostic Test Accuracy
• Bias in Veterinary Research: Types, Sources, and Mitigation
• Cluster Randomized Trials in Veterinary Research: Design and Analysis

References and Further Reading

• Advantages and Limitations of Bacteriophages for the Treatment of Bacterial Infections.. 2019.
• An update on the evidence for pathogenic mechanisms that may link periodontitis and diabetes.. 2018.
• Global Impacts of Western Diet and Its Effects on Metabolism and Health: A Narrative Review.. 2023.
• Neuroimaging of the periaqueductal gray: state of the field.. 2012.
• Bone grafts: which is the ideal biomaterial?. 2019.
• Mechanisms of action of the erector spinae plane (ESP) block: a narrative review.. 2021.
• ARRIVE Guidelines 2.0 for Reporting Animal Research. PLOS Biology, 2020.
• EQUATOR Network Reporting Guidelines. EQUATOR Network.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.

Related Articles

• Conducting Systematic Reviews of Veterinary Therapeutic Interventions
• Conducting Systematic Reviews of Veterinary Diagnostic Test Accuracy
• Conducting Pharmacovigilance Studies in Veterinary Medicine
• How to Write a Research Protocol for Veterinary Studies
• Critical Appraisal of Randomized Controlled Trials in Veterinary Medicine

This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.