European Journal of Clinical Investigation

Cover image for Vol. 46 Issue 6

Edited By: John P.A. Ioannidis

Impact Factor: 2.734

ISI Journal Citation Reports © Ranking: 2014: 30/154 (Medicine General & Internal); 52/123 (Medicine Research & Experimental)

Online ISSN: 1365-2362

Author Guidelines

Revised 8 January 2014

Effective with the 2014 volume, this journal will be published in an online-only format.

Print subscription and single issue sales are available from Wiley's Print-on-Demand Partner. To order online click through to the ordering portal from the journal's subscribe and renew page on Wiley Online Library.


The European Journal of Clinical Investigation (EJCI), in publication since 1970, is a peer-reviewed general-interest biomedical journal with a broad readership. It is the official journal of the European Society for Clinical Investigation (ESCI) and it is published monthly by Wiley. It considers any original contribution from the most sophisticated basic molecular sciences to applied clinical and translational research and evidence-based medicine across a broad range of subspecialties. The EJCI publishes reports of high-quality research that pertain to the genetic, molecular, cellular, or physiological basis of human biology and disease, as well as research that addresses prevalence, diagnosis, course, treatment, and prevention of disease. We are primarily interested in studies directly pertinent to humans, but submission of robust in vitro and animal work is also encouraged. Interdisciplinary work and research using innovative methods and combinations of laboratory, clinical, and epidemiological methodologies and techniques is of great interest to the journal. Several categories of manuscripts (for detailed description see below) are considered: editorials, original articles (also including randomized clinical trials, systematic reviews and meta-analyses), reviews (narrative reviews), opinion articles (including debates, perspectives and commentaries); and letters to the Editor.

If your paper is accepted, the author identified as the formal corresponding author for the paper will receive an email prompting them to login into Author Services; where via the Wiley Author Licensing Service (WALS) they will be able to complete the license agreement on behalf of all authors on the paper.

For authors signing the copyright transfer agreement

If the OnlineOpen option is not selected the corresponding author will be presented with the copyright transfer agreement (CTA) to sign. The terms and conditions of the CTA can be previewed in the samples associated with the Copyright FAQs below:

CTA Terms and Conditions

For authors choosing OnlineOpen

If the OnlineOpen option is selected the corresponding author will have a choice of the following Creative Commons License Open Access Agreements (OAA):

Creative Commons Attribution Non-Commercial License OAA

Creative Commons Attribution Non-Commercial -NoDerivs License OAA

To preview the terms and conditions of these open access agreements please visit the Copyright FAQs hosted on Wiley Author Services and Wiley Online Access.

If you select the OnlineOpen option and your research is funded by The Wellcome Trust and members of the Research Councils UK (RCUK) you will be given the opportunity to publish your article under a CC-BY license supporting you in complying with Wellcome Trust and Research Councils UK requirements. For more information on this policy and the Journal’s compliant self-archiving policy please click here.

For RCUK and Wellcome Trust authors click on the link below to preview the terms and conditions of this license:

Creative Commons Attribution License OAA

To preview the terms and conditions of these open access agreements please visit the Copyright FAQs hosted on Wiley Author Services and Wiley Open Access.

OnlineOpen is available to authors of primary research articles who wish to make their article available to non-subscribers on publication, or whose funding agency requires grantees to archive the final version of their article. With OnlineOpen, the author, the author's funding agency, or the author's institution pays a fee to ensure that the article is made available to non-subscribers upon publication via Wiley Online Library, as well as deposited in the funding agency's preferred archive. For the full list of terms and conditions, click here.

Any authors wishing to send their paper OnlineOpen will be required to complete the payment form available from our website. Prior to acceptance there is no requirement to inform an Editorial Office that you intend to publish your paper OnlineOpen if you do not wish to. All OnlineOpen articles are treated in the same way as any other article. They go through the journal's standard peer-review process and will be accepted or rejected based on their own merit.

Reports on biomedical research involving human subjects must include a statement that informed consent was obtained from each subject or subject's guardian and from the Institutional Review Board.

The corresponding author must verify that the manuscript, including related data, figures and tables, has not been previously reported or published, that the manuscript is not under consideration elsewhere, and that it will not be submitted elsewhere while under review by the EJCI. Any publication restricted in symposia, proceedings, etc. of preliminary results is permitted only in the format of an abstract of 400 words or fewer.

For all manuscripts reporting data from studies involving human participants or animals, formal review and approval by an appropriate institutional review board or ethics committee is required and should be described in the 'Materials and methods' section. For those investigators who do not have formal ethics review committees, the principles outlined in the Declaration of Helsinki should be followed. Reports on biomedical research involving human subjects must include a statement that informed consent was obtained from each subject or subject's guardian. Editors may request that authors provide documentation of the formal review and recommendation from the institutional review board or ethics committee responsible for oversight of the study.

Conflicts of Interest and Financial Disclosures
A conflict of interest may arise when an author has financial or personal relationships or affiliations that could influence (or bias) the author’s decisions, work, or manuscript. All authors are required to disclose all potential conflicts of interest, specific financial interests (including, but not limited to consultancies, employment/affiliation, grants or funding, honoraria, speakers' bureaus, stock ownership or options, expert testimony, royalties, or patents filed, received, pending, or in preparation), and relationships and affiliations (other than those affiliations listed in the title page of the manuscript) relevant to the subject of their manuscript.

All such disclosures must be listed in the Acknowledgment section at the end of the manuscript. Authors without conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject of their manuscript, should include a statement of no such interests in the Acknowledgment section of the manuscript. This information will be included in the published manuscript. The policy requesting disclosure of conflicts of interest applies for all manuscript submissions, including letters to the Editor. Failure to include this information in the manuscript may delay evaluation and review of the manuscript.

Funding/Support and Role of Sponsor
All contributors who do not meet the criteria for authorship must be listed in an acknowledgements section at the end of the manuscript. Financial and material support must also be acknowledged. Authors are required to describe the role of the study sponsor(s), if any, in study design; in collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the manuscript for publication. If the supporting source had no such involvement, the authors should state so. Also, if no specific funding was obtained, this should be stated. This information will be included in the published manuscript.


Editorials are commentaries on current topics or on papers published elsewhere in the issue. Editorials are solicited by the Editor. They should not include an abstract; text should not exceed 1000 words and may have up to 20 references.

Original articles
These reports typically include studies which describe substantial new mechanistic insights into biology and disease, randomized trials (see Randomized Clinical Trials below), intervention studies, cohort studies, cross-sectional studies, case-control studies, epidemiologic assessments, and other observational studies. Each manuscript should clearly state an objective or hypothesis; the design and methods (including the study setting and dates, patients or participants with inclusion and exclusion criteria and/or participation or response rates, or data sources, and how these were selected for the study); the essential features of any interventions; the main outcome measures; the main results of the study; a comment section placing the results in context with the published literature and addressing study limitations; and the conclusions. Data included in research reports must be original. A structured abstract not exceeding 250 words is required; for more information, see below instructions for preparing structured abstracts. Original articles are generally limited to 2700 words (not including abstract, tables, figures, and references), 40 references, and no more than 5 tables and figures.

Randomized Clinical Trials
In this particular type of original study, individuals are randomly allocated to receive or not receive a preventive, therapeutic, or diagnostic intervention and then followed up to determine the effect of the intervention. All randomized clinical trials should include a flow diagram and authors should provide a completed randomized trial checklist (see CONSORT Flow Diagram and Checklist and a trial protocol. Authors of randomized controlled trials are encouraged to submit trial protocols along with their manuscripts. All clinical trials must be registered (before recruitment of the first participant) at an appropriate online public that must be independent of for-profit interest (;;;; Each manuscript should clearly state an objective or hypothesis; the design and methods (including the study setting and dates, patients or participants with inclusion and exclusion criteria, or data sources, and how these were selected for the study); the essential features of any interventions; the main outcome measures; the main results of the study; a comment section placing the results in context with the published literature and addressing study limitations; and the conclusions. Data included in research reports must be original. A structured abstract not exceeding 250 words is required; for more information, see below instructions for preparing structured abstracts. Clinical trials are limited to 2700 words (not including abstract, tables, figures, and references), 40 references, and no more than 5 tables and figures.

Systematic reviews and meta-analyses
Systematic reviews and meta-analyses are a particular type of original articles that perform systematic, critical assessment of literature and data sources pertaining to clinical topics, emphasizing factors such as cause, diagnosis, prognosis, therapy, or prevention. All articles or data sources should be searched for and selected systematically for inclusion and critically evaluated, and the search and selection process should be described in detail in the manuscript. The specific type of study or analysis, population, intervention, exposure, and tests or outcomes should be described for each article or data source. A structured abstract of less than 250 words is required; for more information, see instructions below for preparing structured abstracts. The text is limited to 3500 words (not including abstract, tables, figures, and references); about 4 tables (a flow diagram that depicts search and selection processes as well as evidence tables should be included) – and no reference limit.

Narrative Reviews
Narrative reviews are especially suitable for describing cutting-edge and evolving developments in clinical medicine, basic research or even clinical implications of basic research and discussing those developments in light of underlying theory. Narrative reviews are usually commissioned. A structured abstract of less than 250 words is required; for more information, see instructions below for preparing structured abstracts. The text is limited to 3500 words (not including abstract, tables, figures, and references); about 4 tables (a flow diagram that depicts search and selection processes as well as evidence tables should be included) – and no more than 70 references.

Opinion articles
Opinion articles are almost always commissioned. The debate section provides a forum for confronting viewpoints, discussion, and examination of challenging issues and difficult questions in clinical medicine, research, public health, or health policy. The section uses a “view-counterview” or “point-counterpoint” format, in which 2 articles address the topic or issue and present differing viewpoints or positions. Manuscripts should be well argued, cogent, and scholarly, with appropriate documentation for scientific content and factual assertions. The goal of this section is that lines of reasoning would lead to a constructive discussion so that the issues would be effectively engaged for readers. Debates do not have an abstract. The opinion part also publishes short, thoughtful essays (perspective articles) from well-known experts on issues that affect both the medical community and society at large. Perspective articles provide opinions on important and provocative subjects as well as views on unsettled questions of diagnosis and treatment, particularly questions arising on common, important clinical issues. Perspectives do not have an abstract. 3-6 bullet points summarizing key messages may be used at the discretion of the authors. Maximum length: up to 2000 words of text (excluding references); about 2 tables or figures—and no more than 30 references (all double-spaced). Commentaries address nearly any significant topic in medicine, public health, research, or health policy and generally are not linked to a specific article. Commentaries should be well focused, scholarly, and clearly presented and must have no more than 3 authors. Maximum length: up to 1300 words of text; they may also include 1 small table or figure and no more than 15 references (all double-spaced). They should not include an abstract.

Letters to the Editor
Letters discussing a recent EJCI article should be received within 10 weeks of the article’s publication and should not exceed 400 words of text and 5 references. The text of letters should include the names, academic degrees, and primary institutional affiliations for all authors, and the e-mail address for the corresponding author. Letters may be condensed at the Editor's discretion. Letter in Reply. Replies by authors should not exceed 500 words of text and 6 references. Other letters with content not pertinent to material previously published in the journal (e.g. case reports or interesting observations) may be occasionally considered for publication and length limitations are the same.

Reporting standards for research
The EJCI complies with main reporting standards for key types of research, including clinical trials (CONSORT and its extensions), meta-analyses (PRISMA), diagnostic tests (STARD), prognostic tumor markers (REMARK), microarrays (MIAME), observational studies (STROBE), genetic epidemiology (STREGA) and others as outlined in the EQUATOR website and in the EQUATOR article published in the first issue of January 2010 of EJCI ( When a study is of a type that needs to adhere to such EQUATOR-listed standards, the authors should make appropriate citation to them to mention that the reporting is compliant with these standards.


Manuscript Preparation
All copy must be typed double-spaced with 1-inch margins and 12-point font size, numbered consecutively, and beginning with the title page. Do not justify lines. Do not use line numbering. Double-space throughout, including Title page, Abstract, text (divided into the following sections: Introduction, Materials and methods, Results, and Discussion), Acknowledgments, References, Legends, and Tables.

Length of Manuscript
While the Editors occasionally approve nonconforming manuscripts, they do so only when they are considered to possess exceptional merit. Submissions that do not conform to recommended space limitations are subjected to a particularly rigorous editorial review and are thus less likely to be accepted than those that fall within recommended guidelines (see above detailed description of article types).

Style of Writing
The style of writing should conform to acceptable English usage and syntax. Slang, medical jargon, obscure abbreviations, and abbreviated phrasing are to be avoided.

Title Page (page 1 of manuscript)
Titles should not exceed 70 characters, including punctuation and spacing. Avoid using declarative sentences or questions as titles. Give full names, highest academic degrees, and institutional affiliations of all authors. Designate a corresponding author and include a complete mailing address, telephone number, fax number, and e-mail address. Specify the address to which requests for reprints should be sent. Also include on the title page a word-character count of the complete text.

Abstract (page 2 of manuscript)
Include a structured abstract not exceeding 250 words and a maximum of six keywords for original articles and reviews. Abstracts should be organized and formatted according to the following headings: Background, Materials and methods, Results, and Conclusions. Authors may substitute 'Materials and methods' for 'Design'. Opinion articles do not require an abstract.

Describe statistical methods with enough detail to enable a knowledgeable reader with access to the original data to reproduce the reported results. When possible, quantify findings and present them with appropriate indicators of measurement error or uncertainty (such as confidence intervals). Avoid relying solely on statistical hypothesis testing, such as the use of P values, which fails to convey important quantitative information. EJCI encourages the use of Bayesian methods in the results and their interpretation. Authors should strongly consider discussing the credibility of their findings, regardless of the P-values or other statistics observed, as well as how their results and findings modify prior evidence. Authors would benefit from following the suggestions of reporting standards and guidance for each type of research as listed in EQUATOR (see above reporting standards).

Put a general description of methods in the 'Materials and methods' section. Restrict tables and figures to those needed to explain the argument of the article and to assess its support. Use graphs as an alternative to tables with many entries; do not duplicate data in graphs and tables. Define statistical terms, abbreviations, and most symbols.

Except for units of measurement, abbreviations are strongly discouraged and should not appear in the title or abstract. All abbreviations must be defined at the first mention and should be coined only for unwieldy names that occur frequently.

Units of Measure
Laboratory values are expressed using conventional units of measure, with relevant Systéme International (SI) conversion factors expressed secondarily (in parentheses) only at first mention. Articles that contain numerous conversion factors may list them together in a paragraph at the end of the 'Materials and methods' section. In tables and figures, a conversion factor to SI units should be provided in a footnote or legend. The metric system is preferred for the expression of length, area, mass, and volume.

Drug Names
The generic name of a drug is preferred in almost all instances. If it is necessary to include the brand (trade) name for reproduction or interpretation of the study, the brand name should be given parenthetically, following the generic name, at first mention in the abstract, text, and each figure or table in which it appears. In addition, the brand name and supplier’s name and location should be given in the 'Materials and methods' section. In the case in which a manuscript is comparing various brands of a single product, or in which an adverse event is described that might be unique to a single brand of product, both the brand name and generic name should appear at first mention and the brand name(s) should be used thereafter.

Gene Names, Symbols, and Accession Numbers
Authors describing genes or related structures in a manuscript should include the names and official symbols provided by the US National Center for Biotechnology Information (NCBI). Before submission of a research manuscript reporting on large genomic data sets (e.g. protein or DNA sequences), the data sets should be deposited in a publicly available database, such as NCBI’s GenBank, and a complete accession number (and version number, if appropriate) must be provided in the 'Materials and methods' section or the Acknowledgments section of the manuscript. Authors of microarray papers should include in their submission the information recommended by the MIAME guidelines. Authors should also submit their experimental details to one of the publicly available databases (ArrayExpress or GEO).

Acknowledgment Section
(See also above under 'Funding/Support and Role of Sponsor' above)
List all persons who have made substantial contributions to the work reported in the manuscript (including writing and editing assistance), but who are not authors; any financial interest in the subject matter or materials discussed in the manuscript; any research or project support/funding; grant support. Authors should also obtain written permission to include the names of individuals in the Acknowledgement section.

All persons listed as authors must have contributed substantially to the design, performance, analysis, or reporting of the work and are required to indicate their specific contribution. The specific requirements for authorship have been defined by the International Committee of Medical Journal Editors (ICMJE; Examples of authors' contributions are: 'designed research/study', 'performed research/study', 'contributed important reagents', 'collected data', 'analyzed data', 'wrote paper' etc. This information must be included in the submitted manuscript and will be published in a separate paragraph at the end of the paper if accepted for publication. The corresponding author is responsible for obtaining permission from all co-authors for the submission of any version of the manuscript and for any changes in authorship.

We recommend the use of a tool such as Reference Manager for reference management and formatting. Reference Manager reference styles can be searched for here.

References should be numbered consecutively in the order in which they are first mentioned in the text, and should appear as numbers in square brackets. The reference list should show the references in numerical order. Work that has not been accepted for publication and personal communications should not appear in the reference list. List 6 authors, followed by 'et al' if the number exceeds 6. An example of a correct reference is given below:

1 Parkin DM, Clayton D, Black RJ, Masuyer E, Friedl HP, Ivanov E, et al. Childhood leukaemia in Europe after Chernobyl: 5 year follow-up. Br J Cancer 1996;73:1006-12.

Tables, Illustrations, Legends
All tables and illustrations should be numbered in the order of their citation in the text. Include a title for each table and figure—a brief, succinct phrase, preferably no longer than 15 words. Tables and illustrations should be original work and only rarely should they be reproduced material.

Tables should be able to stand alone, without the need to refer to the text. Table titles should convey complete information about the study population, research question, methods, and sample size. Table footnotes should include adequate descriptions of outcome variables, covariates in multivariate models, and model diagnostics, where relevant. All tables should be numbered in the order of their citation in the text. If a table must be continued, repeat the title on a second sheet, followed by “cont.” Make certain each item in the table is in its own table cell. Do not use paragraph returns (to start new rows) or tabs (to start new columns) to format the table.

Each figure should have a legend, and these should be listed together on a separate sheet. In the full-text online edition of the journal, figure legends may be truncated in abbreviated links to the full screen version. Therefore, the first 100 characters of any legend should inform the reader of key aspects of the figure. We would like to receive your artwork in electronic form. Please save vector graphics (e.g. half-tones) in Tagged Image File Format (TIFF). Ideally, vector graphics that have been saved in metafile (.WMF) or pict (.PICT) format should be embedded within the body of the text file. Detailed information on ideal digital illustration standards can be found at Wiley Author Services.

Colour illustrations are welcome and published free of charge.

Manuscripts - Submission Requirements
The journal prefers to receive all manuscript submissions electronically. To submit a manuscript, please follow the instructions below. Microsoft Word documents should preferably be saved as an older (.doc) file type.

Getting Started

1. Point your web browser to the journal’s Manuscript Central homepage (
2. Log-in (click the ‘Create Account’ option if you are a first-time user of Manuscript Central) and select ‘Author Center’.

Submitting Your Manuscript

3. After you have logged in, click the ‘Submit a Manuscript’ link in the menu bar; enter data and answer questions as appropriate, clicking the ‘Next’ button on each screen to save your work and advance to the next screen, as necessary.
4. You are required to upload your files.
    Click on the ‘Browse’ button and locate the file on your computer, and select the designation of each file in the drop down next to the Browse button.
      When you have selected all files you wish to upload, click the ‘Upload Files’ button.
5. Review your submission (in both PDF and HTML formats) before sending to the Journal. Click the ‘Submit’ button when you are finished reviewing.

You may suspend a submission at any phase before clicking the ‘Submit’ button and save it to submit later. After submission, you will receive a confirmation e-mail. You can also access Manuscript Central any time to check the status of your manuscript. The Journal will inform you by e-mail once a decision has been made.

Cover Letter
Include a cover letter and complete contact information for the corresponding author (postal/mail address, e-mail address, and telephone and fax numbers) and whether the authors have published or submitted any related papers from the same study (see Policies above).

Previous submission in other journals
We strongly encourage authors to share with us the comments of previous reviewers and their responses to them. We understand that authors may have tried other journals first and that many excellent papers are rejected simply based on perceived priority in journals with extremely limited space or, sometimes, from erroneous judgments. A cogent response to previous comments will weigh very positively in our evaluation towards publication in the EJCI and may expedite the time to acceptance.

Suggestions for reviewers
The EJCI is a peer-reviewed journal. Authors may suggest in their covering letter the names, addresses, telephone and fax numbers and email address of at least three reviewers with appropriate expertise. These individuals should not be involved in the work of the authors in any possible way for the last three years. In addition, any reviewers that the authors would prefer to exclude should be listed with the reason for exclusion. Nevertheless, the journal reserves the right of final selection of reviewers.

The corresponding author will receive an e-mail alert containing a link to a website. A working e-mail address must therefore be provided for the corresponding author. The proof can be downloaded as a PDF (portable document format) file from this site. Acrobat Reader will be required in order to read this file. This software can be downloaded (free of charge) from Adobe.

This will enable the file to be opened, read on screen and printed out in order for any corrections to be added. Further instructions will be sent with the proof. Hard copy proofs will be posted if no e-mail address is available. Excessive changes made by the author in the proofs, excluding typesetting errors, will be charged separately.

Page proof corrections should be returned within three days of receipt.

The corresponding author will receive a free PDF offprint that can be downloaded via Author Services. Please sign up for the service if you would like to access your free article PDF offprint and enjoy the many other benefits the service offers. Visit Author Services for more information.

Early View
European Journal of Clinical Investigation is covered by Wiley's Early View service. Early View articles are complete full-text articles published online in advance of their publication in a regular issue. Articles are therefore available as soon as they are ready, rather than having to wait for the next scheduled regular issue. Early View articles are complete and final. They have been fully reviewed, revised and edited for publication, and the authors' final corrections have been incorporated. Because they are in final form, no changes can be made after online publication. The nature of Early View articles means that they do not yet have volume, issue of page numbers, so Early View articles cannot be cited in the traditional way. They are therefore given a Digital Object Identifier (DOI), which allows the article to be cited and tracked before it is allocated to an issue. After online publication, the DOI remains valid and can continue to be used to cite and access the article.

Online production tracking through Wiley’s Author Services
Author Services enables authors to track their article – once it has been accepted – through the production process to publication online. Authors can check the status of their articles online and choose to receive automated e-mails at key stages of production. The author will receive an e-mail with a unique link that enables them to register and have their article automatically added to the system. Please ensure that a complete e-mail address is provided when submitting the manuscript. Visit Author Services for more details on online production tracking and for a wealth of resources including FAQs and tips on article preparation, submission and more.

Note to NIH Grantees
Pursuant to NIH mandate, Wiley will post the accepted version of contributions authored by NIH grant-holders to PubMed Central upon acceptance. This accepted version will be made publicly available 12 months after publication.
For further information, see