Review

Reviews provide comprehensive and authoritative coverage of a topic area. Trials does not consider Reviews addressing clinical questions and advise authors consider submitting systematic reviews addressing clinical questions to our sister-journal, Systematic Reviews.

Key aims of Reviews are to provide systematic and substantial coverage of mature subjects, evaluations of progress in specified areas, and/or critical assessments of emerging technologies.

Trials strongly encourages that all datasets on which the conclusions of the paper rely should be available to readers. We encourage authors to ensure that their datasets are either deposited in publicly available repositories (where available and appropriate) or presented in the main manuscript or additional supporting files whenever possible. Please see Springer Nature’s information on recommended repositories.

Authors submitting to Trials can now opt-in to a service called In Review, which provides authors with on-demand information on the status of their manuscript, enables them to share their work with funders and others, and allows their wider community to comment and collaborate - all whilst their manuscript is under review. Please see here for full details.

If your article reports the results of research on research and you have registered your work with the Research on Research (RoR) registry, please include the registry record URL in your manuscript.

For completed systematic reviews, Trials requires the submission of a populated PRISMA checklist and flow diagram. The flow diagram should be included in the main body of the text and the checklist should be provided as an additional file, both the flow diagram and the checklist should be referenced in the text. Submissions received without these elements will be returned to the authors as incomplete. A Word file of the checklist and flow diagram can be downloaded here.

It is understood that for some systematic reviews certain aspects of the report may not comply fully with the PRISMA checklist. The checklist will not be used as a tool for judging the suitability of manuscripts for publication in Trials, but is intended as an aid to authors to clearly, completely, and transparently let reviewers and readers know what authors did and found. Using the PRISMA guideline to write the completed systematic review report, completing the PRISMA checklist, and constructing a flow diagram are likely to optimize the quality of reporting and make the peer review process more efficient.

The information below details the section headings that you should include in your manuscript and what information should be within each section.

Please note that your manuscript must include a 'Declarations' section including all of the subheadings (please see below for more information).

Title page

The title page should:

• present a title that includes, if appropriate, the study design
• list the full names, institutional addresses and email addresses for all authors
  • if a collaboration group should be listed as an author, please list the Group name as an author. If you would like the names of the individual members of the Group to be searchable through their individual PubMed records, please include this information in the “Acknowledgements” section in accordance with the instructions below
  • Large Language Models (LLMs), such as ChatGPT, do not currently satisfy our authorship criteria. Notably an attribution of authorship carries with it accountability for the work, which cannot be effectively applied to LLMs. Use of an LLM should be properly documented in the Methods section (and if a Methods section is not available, in a suitable alternative part) of the manuscript
• indicate the corresponding author

Abstract

The Abstract of the manuscript should not exceed 350 words and must be structured into separate sections:

• Background: the context and purpose of the review, including the review question.
• Methods: how the review was performed, including data sources, study eligibility criteria, participants and interventions; study appraisal and statistical tests used.
• Results: the main findings, including results of search and assessment of evidence base.
• Conclusions: brief summary and potential implications for policy/management and research.
• Registration: authors are asked to provide registration information about the systematic review, including a registration number, if available.

Keywords

Three to ten keywords representing the main content of the article.

Background

This section should be written in a way that is accessible to researchers without specialist knowledge in that area and must clearly explain why a systematic review on this topic was needed and what it aimed to contribute to the field. The section should end with the main question(s) of the review and a brief statement of what is being reported with reference to participants, interventions, outcomes and study design (PICO).

You may also wish to use this section to mention discussions that have been organized with stakeholders and the role of stakeholders in the formulation of the question should be described and explained.

Methods

This should include a clear description of all stages of the review process and the design of the review, the setting, the type of participants or materials involved, and the type of analysis, including:

• Searches: search terms and languages, comprehensiveness and effectiveness of the search, search strings and/or combinations of searches, databases, searches for grey literature i.e. contacts, searches on internet, use of specific search terms or strings, filtering or limitations and literature provided directly by stakeholders. Tables and lists of bibliographies, search terms and databases or other information can be provided as additional files.
• Study inclusion and exclusion criteria: provide explanation about the rationale followed to include/exclude articles, including specific study characteristics (PICO, length of follow-up, etc), specific report characteristics (year of publication, language, etc) and study selection procedures (screening).
• Potential effect modifiers and reasons for heterogeneity: potential effect modifiers and reasons for heterogeneity should be discussed here and should be identified by discussions with stakeholders and experts as early as possible.
• Study quality assessment: how you are planning to or have assessed the study quality. Describe the methods used for assessing risk of bias of individual studies, including specification of whether this was done at the study or outcome level, and how this information was used in any data synthesis. Discussions with experts and stakeholders at early stages should help identify the methodological standards for the topic of interest.
• Data extraction strategy: what sort of data do you expect to find or have finally extracted and how you computed effect sizes and their variability.
• Data synthesis and presentation: report the qualitative and quantitative methods you used to synthesize and present the data, as well as elements you anticipate or have identified such as effect modifiers, type of methodologies and their current appraisal, biases etc. Describe any additional analyses (sensitivity, sub-group analysis, meta-analysis) done and indicate which were pre-specified.

For an example of how a search strategy should be presented, see the Cochrane Reviewer's Handbook.

If existing, make reference to an accessible review protocol. Authors are additionally asked to provide registration information about the systematic review, including a registration number, if available.

Results and discussion

The results and discussion should be presented separately. The results and discussion sections may also be broken into subsections with short, informative headings. Results of each stage of the review should be clearly reported, including:

• Review statistics: i.e. the number of articles found in the search and included at each inclusion/exclusion level, along with any relevant information on the distribution of the studies found (e.g. geographical location and source of study). A flow diagram (conforming to relevant reporting guidelines e.g. PRISMA) reporting the inclusion/exclusion process should be presented.
• Study quality assessment: a summary of what the different studies found, the confidence in the results of the different studies, what biases were present in each of the studies, and quality of the different studies needs to be included.
• Quantitative synthesis/Meta-analysis (when possible): if effect sizes can be calculated for the included studies which measure similar outcomes then a quantitative assessment of these effect sizes should be carried out, including summary statistics of the mean effect, confidence in the mean, the range of effects and sources of heterogeneity in the effect. Please note, if there are a large number of confounding variables or outcome measures such that effect sizes which measure the same outcome cannot be calculated then a summary statistic should not be calculated.
• Evidence of effectiveness: a detailed evaluation of the information on the impact of the intervention that the papers give, what evidence of an effect is there and what is the strength of the evidence including the critical appraisal of the articles. In addition, there needs to be an unbiased assessment of what level of evidence the studies provide.

Speculation within the discussion section should be limited only to suggestions for further enquiry or analysis e.g. potential reasons for heterogeneity in outcome, including the possible effect modifiers and impact of variation in the study variables such as experimental design. A section on review limitations should normally be included, including limitations due to the search strategy and bias in articles found, as well as limitations due to underlying bias within studies found such as baseline bias and confounding variables. Gaps in the information provided by the studies should also be highlighted.

Conclusions

This should state clearly the main conclusions of the article and give a clear explanation of the implication for policy/management summarizing the state of the evidence base and the extent to which this informs decision making in relation to the review question and any measure of uncertainty surrounding the outcome. In addition, it should also provide a clear explanation on the implication for research summarizing the shortcomings of the current evidence base in terms of knowledge gaps and the need for primary research.

List of abbreviations

If abbreviations are used in the text they should be defined in the text at first use, and a list of abbreviations should be provided.

All manuscripts must contain the following sections under the heading 'Declarations':

• Ethics approval and consent to participate
• Consent for publication
• Availability of data and materials
• Competing interests
• Funding
• Authors' contributions
• Acknowledgements
• Authors' information (optional)

Please see below for details on the information to be included in these sections.

If any of the sections are not relevant to your manuscript, please include the heading and write 'Not applicable' for that section. 

Ethics approval and consent to participate

Manuscripts reporting studies involving human participants, human data or human tissue must:

• include a statement on ethics approval and consent (even where the need for approval was waived)
• include the name of the ethics committee that approved the study and the committee’s reference number if appropriate

Studies involving animals must include a statement on ethics approval and for experimental studies involving client-owned animals, authors must also include a statement on informed consent from the client or owner.

See our editorial policies for more information.

If your manuscript does not report on or involve the use of any animal or human data or tissue, please state “Not applicable” in this section.

Consent for publication

If your manuscript contains any individual person’s data in any form (including any individual details, images or videos), consent for publication must be obtained from that person, or in the case of children, their parent or legal guardian. All presentations of case reports must have consent for publication.

You can use your institutional consent form or our consent form if you prefer. You should not send the form to us on submission, but we may request to see a copy at any stage (including after publication).

See our editorial policies for more information on consent for publication.

If your manuscript does not contain data from any individual person, please state “Not applicable” in this section.

Availability of data and materials

All manuscripts must include an ‘Availability of data and materials’ statement. Data availability statements should include information on where data supporting the results reported in the article can be found including, where applicable, hyperlinks to publicly archived datasets analysed or generated during the study. By data we mean the minimal dataset that would be necessary to interpret, replicate and build upon the findings reported in the article. We recognise it is not always possible to share research data publicly, for instance when individual privacy could be compromised, and in such instances data availability should still be stated in the manuscript along with any conditions for access.

Authors are also encouraged to preserve search strings on searchRxiv https://searchrxiv.org/, an archive to support researchers to report, store and share their searches consistently and to enable them to review and re-use existing searches. searchRxiv enables researchers to obtain a digital object identifier (DOI) for their search, allowing it to be cited. 

Data availability statements can take one of the following forms (or a combination of more than one if required for multiple datasets):

• The datasets generated and/or analysed during the current study are available in the [NAME] repository, [PERSISTENT WEB LINK TO DATASETS]
• The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.
• All data generated or analysed during this study are included in this published article [and its supplementary information files].
• The datasets generated and/or analysed during the current study are not publicly available due [REASON WHY DATA ARE NOT PUBLIC] but are available from the corresponding author on reasonable request.
• Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.
• The data that support the findings of this study are available from [third party name] but restrictions apply to the availability of these data, which were used under license for the current study, and so are not publicly available. Data are however available from the authors upon reasonable request and with permission of [third party name].
• Not applicable. If your manuscript does not contain any data, please state 'Not applicable' in this section.

More examples of template data availability statements, which include examples of openly available and restricted access datasets, are available here.

BioMed Central strongly encourages the citation of any publicly available data on which the conclusions of the paper rely in the manuscript. Data citations should include a persistent identifier (such as a DOI) and should ideally be included in the reference list. Citations of datasets, when they appear in the reference list, should include the minimum information recommended by DataCite and follow journal style. Dataset identifiers including DOIs should be expressed as full URLs. For example:

Hao Z, AghaKouchak A, Nakhjiri N, Farahmand A. Global integrated drought monitoring and prediction system (GIDMaPS) data sets. figshare. 2014. http://dx.doi.org/10.6084/m9.figshare.853801

With the corresponding text in the Availability of data and materials statement:

The datasets generated during and/or analysed during the current study are available in the [NAME] repository, [PERSISTENT WEB LINK TO DATASETS].^{[Reference number]} 

If you wish to co-submit a data note describing your data to be published in BMC Research Notes, you can do so by visiting our submission portal. Data notes support open data and help authors to comply with funder policies on data sharing. Co-published data notes will be linked to the research article the data support (example).

Competing interests

All financial and non-financial competing interests must be declared in this section.

See our editorial policies for a full explanation of competing interests. If you are unsure whether you or any of your co-authors have a competing interest please contact the editorial office.

Please use the authors initials to refer to each authors' competing interests in this section.

If you do not have any competing interests, please state "The authors declare that they have no competing interests" in this section.

Funding

All sources of funding for the research reported should be declared. If the funder has a specific role in the conceptualization, design, data collection, analysis, decision to publish, or preparation of the manuscript, this should be declared.

Authors' contributions

The individual contributions of authors to the manuscript should be specified in this section. Guidance and criteria for authorship can be found in our editorial policies.

Please use initials to refer to each author's contribution in this section, for example: "FC analyzed and interpreted the patient data regarding the hematological disease and the transplant. RH performed the histological examination of the kidney, and was a major contributor in writing the manuscript. All authors read and approved the final manuscript."

Acknowledgements

Please acknowledge anyone who contributed towards the article who does not meet the criteria for authorship including anyone who provided professional writing services or materials.

Authors should obtain permission to acknowledge from all those mentioned in the Acknowledgements section.

See our editorial policies for a full explanation of acknowledgements and authorship criteria.

If you do not have anyone to acknowledge, please write "Not applicable" in this section.

Group authorship (for manuscripts involving a collaboration group): if you would like the names of the individual members of a collaboration Group to be searchable through their individual PubMed records, please ensure that the title of the collaboration Group is included on the title page and in the submission system and also include collaborating author names as the last paragraph of the “Acknowledgements” section. Please add authors in the format First Name, Middle initial(s) (optional), Last Name. You can add institution or country information for each author if you wish, but this should be consistent across all authors.

Please note that individual names may not be present in the PubMed record at the time a published article is initially included in PubMed as it takes PubMed additional time to code this information.

Authors' information

This section is optional.

You may choose to use this section to include any relevant information about the author(s) that may aid the reader's interpretation of the article, and understand the standpoint of the author(s). This may include details about the authors' qualifications, current positions they hold at institutions or societies, or any other relevant background information. Please refer to authors using their initials. Note this section should not be used to describe any competing interests.

Footnotes

Footnotes can be used to give additional information, which may include the citation of a reference included in the reference list. They should not consist solely of a reference citation, and they should never include the bibliographic details of a reference. They should also not contain any figures or tables.

Footnotes to the text are numbered consecutively; those to tables should be indicated by superscript lower-case letters (or asterisks for significance values and other statistical data). Footnotes to the title or the authors of the article are not given reference symbols.

Always use footnotes instead of endnotes.

Examples of the Vancouver reference style are shown below.

See our editorial policies for author guidance on good citation practice

Web links and URLs: All web links and URLs, including links to the authors' own websites, should be given a reference number and included in the reference list rather than within the text of the manuscript. They should be provided in full, including both the title of the site and the URL, as well as the date the site was accessed, in the following format: The Mouse Tumor Biology Database. http://tumor.informatics.jax.org/mtbwi/index.do. Accessed 20 May 2013. If an author or group of authors can clearly be associated with a web link, such as for weblogs, then they should be included in the reference.

Example reference style:

Article within a journal

Smith JJ. The world of science. Am J Sci. 1999;36:234-5.

Article within a journal (no page numbers)

Rohrmann S, Overvad K, Bueno-de-Mesquita HB, Jakobsen MU, Egeberg R, Tjønneland A, et al. Meat consumption and mortality - results from the European Prospective Investigation into Cancer and Nutrition. BMC Medicine. 2013;11:63.

Article within a journal by DOI

Slifka MK, Whitton JL. Clinical implications of dysregulated cytokine production. Dig J Mol Med. 2000; doi:10.1007/s801090000086.

Article within a journal supplement

Frumin AM, Nussbaum J, Esposito M. Functional asplenia: demonstration of splenic activity by bone marrow scan. Blood 1979;59 Suppl 1:26-32.

Book chapter, or an article within a book

Wyllie AH, Kerr JFR, Currie AR. Cell death: the significance of apoptosis. In: Bourne GH, Danielli JF, Jeon KW, editors. International review of cytology. London: Academic; 1980. p. 251-306.

OnlineFirst chapter in a series (without a volume designation but with a DOI)

Saito Y, Hyuga H. Rate equation approaches to amplification of enantiomeric excess and chiral symmetry breaking. Top Curr Chem. 2007. doi:10.1007/128_2006_108.

Complete book, authored

Blenkinsopp A, Paxton P. Symptoms in the pharmacy: a guide to the management of common illness. 3rd ed. Oxford: Blackwell Science; 1998.

Online document

Doe J. Title of subordinate document. In: The dictionary of substances and their effects. Royal Society of Chemistry. 1999. http://www.rsc.org/dose/title of subordinate document. Accessed 15 Jan 1999.

Online database

Healthwise Knowledgebase. US Pharmacopeia, Rockville. 1998. http://www.healthwise.org. Accessed 21 Sept 1998.

Supplementary material/private homepage

Doe J. Title of supplementary material. 2000. http://www.privatehomepage.com. Accessed 22 Feb 2000.

University site

Doe, J: Title of preprint. http://www.uni-heidelberg.de/mydata.html (1999). Accessed 25 Dec 1999.

FTP site

Doe, J: Trivial HTTP, RFC2169. ftp://ftp.isi.edu/in-notes/rfc2169.txt (1999). Accessed 12 Nov 1999.

Organization site

ISSN International Centre: The ISSN register. http://www.issn.org (2006). Accessed 20 Feb 2007.

Dataset with persistent identifier

Zheng L-Y, Guo X-S, He B, Sun L-J, Peng Y, Dong S-S, et al. Genome data from sweet and grain sorghum (Sorghum bicolor). GigaScience Database. 2011. http://dx.doi.org/10.5524/100012.

See General formatting guidelines for information on how to format figures, tables and additional files.