Information for authors

On  the  Cochrane training website page authors of systematic reviews will find everything they need to conduct their reviews https://training.cochrane.org/online-learning/author-guidelines . 

The aim of a Cochrane review is to assess systematically and thoroughly the best possible scientific evidence about the effects of a health care intervention(s). Everything about the review should aim to minimise the possibility of ending in a conclusion that is biased (systematic error either through domains or through design) or based on play of chance (random errors). This means:

  • the conduct of the review and its analyses should follow clear, pre-specified criteria - with checks along the way
  • it should be easy to understand
  • any conflict of interest of the people doing the review should be declared
  • effort must be made to find every possible study that might be eligible for the review
  • the studies included in the review's analyses should be ones which have as little bias in them as possible
  • outcomes that are important to the consumers of the interventions must be considered - whether or not they have been measured by researchers - to avoid conclusions being based on a narrow picture of relaity
  • the analyses should take into account statistical methods that may reduce the risk of random errors
  • the final review should follow the pre-specified criteria, addressing all the important issues originally raised, and highlight any issues and gaps in the information that should be addressed by researchers in future

People who wish to propose a review title should visit https://www.cochranelibrary.com/about/author-information for detailed information. The title can be agreed in advance with the CHBG Editorial Team office.

References for every article or book identified in the text of the manuscript need to be listed, complying with Cochrane standard format for references and citations (see the Cochrane Style Manual).

Authors must get familiar with and must follow the Conflicts of interest and Cochrane Reviews.

At a CHBG Editorial Team Group meeting in Copenhagen in April 2009, CHBG editors decided that CHBG review authors should be encouraged to use trial sequential analyses of their important meta-analyses. In the recent years, the central Cochrane editorial team suggested the use of Trial Sequential Analysis only as a sensitivity analysis of imprecision and compare this assessment with the assessment of imprecision with GRADE (Thomas 2019).

The Trial Sequential Analysis (TSA) software is free to download and use. The Trial Sequential Analysis Manual can be downloaded from the TSA website. Review authors should follow the instructions at www.ctu.dk/tools-and-links/tools-and-links.aspx when creating images for publication in their reviews with RevMan web.  

Please contact the CHBG editorial Team office for an example of Trial Sequential Analysis text in protocols and reviews. 

Reporting of reviews

For policies on the reporting of reviews (for example on the discussion of results, the use of tables and figures, and the naming of studies), authors must follow the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions.

References suggested for use in systematic reviews follow below.

Als-Nielsen B, Chen W, Gluud C, Kjaergard LL. Association of funding and conclusions in randomized drug trials: a reflection of treatment effect or adverse events. JAMA 2003;290:921-8.

Balshem H, Helfand M, Schunemann HJ, Oxman AD, Kunz R, Brozek J, et al. GRADE guidelines: 3. Rating the quality of evidence. Journal of Clinical Epidemiology 2011;64(4):401-6.

Begg CB, Mazumdar M. Operating characteristics of a rank correlation test for publication bias. Biometrics 1994;50:(4):1088-101.

Chan AW, Tetzlaff JM, Altman DG, Laupacis A, Gøtzsche PC, Krleža-Jerić K, et al. SPIRIT 2013 Statement: defining standard protocol items for clinical trials. Annals of Internal Medicine 2013;158:200-7.

Chan A-W, Tetzlaff JM, Gøtzsche PC, Altman DG, Mann H, Berlin J, Dickersin K, Hróbjartsson A, Schulz KF, Parulekar WR, Krleža-Jerić K, Laupacis A, Moher D. SPIRIT 2013 Explanation and Elaboration: Guidance for protocols of clinical trials. BMJ 2013;346:e7586.

Deeks JJ, Higgins JPT, Altman DG (editors). Chapter 10: Analysing data and undertaking meta-analyses. In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.0 (updated July 2019). Cochrane, 2019. Available from www.training.cochrane.org/handbook.

DeMets DL. Methods of combining randomized clinical trials: strengths and limitations. Statistics in Medicine 1987;6(3):341-50.

DerSimonian R, Laird N. Meta-analysis in clinical trials. Controlled Clinical Trials 1986;7(3):177-88.

Egger M, Jüni P, Bartlett C, Holenstein F, Sterne J. How important are comprehensive literature searches and the assessment of trial quality in systematic reviews? Empirical study. Health Technology Assessment 2003;7:1-76.

Egger M, Smith GD, Schneider M, Minder C. Bias in meta-analysis detected by a simple graphical test. BMJ (Clinical Research Ed.) 1997;315(7109):629-34.

Fisher RA. On the interpretation of χ2 from contingency tables, and the calculation of P. Journal of the Royal Statistical Society 1922;85(1):87-94. 

Garattini S, Jakobsen JC, Wetterslev J, Bertelé V, Banzi R, Rath A, et al. Evidence-based clinical practice: overview of threats to the validity of evidence and how to minimise them. European Journal of Internal Medicine 2016;32:13-21. 

Gluud LL, Thorlund K, Gluud C, Woods L, Harris R, Sterne JA. Correction: reported methodologic quality and discrepancies between large and small randomized trials in meta-analyses. Annals of Internal Medicine 2008;149(3):219. 

GRADEpro GDT: GRADEpro Guideline Development Tool [Software]. McMaster University, 2015 (developed by Evidence Prime, Inc.). Available from gradepro.org.

Schünemann H, Brożek J, Guyatt G, Oxman A, editors. GRADE handbook for grading quality of evidence and strength of recommendations. Updated October 2013. The GRADE Working Group, 2013. Available fromguidelinedevelopment.org/handbook. When referring to a specific chapter or subsection refer to it by the title and section number, not page numbers. Example: Chapter authors in Schünemann H, Brożek J, Guyatt G, Oxman A, editors. GRADE handbook for Grading quality of evidence and strength of recommendations. Version XX [updated XX 2014].Guyatt G, Andrews J, Oxman AD, Alderson P, Dahm P, Falck-Ytter Y, et al. GRADE guidelines: 15. Going from evidence to recommendations: the significance and presentation of recommendations. Journal of Clinical Epidemiology 2013;66(7):719-25.

Guyatt G, Oxman AD, Akl EA, Kunz R, Vist G, Brozek J, et al. GRADE guidelines: 1. Introduction-GRADE evidence profiles and summary of findings tables. Journal of Clinical Epidemiology 2011;64(4):383-94.

Guyatt G, Oxman AD, Sultan S, Brozek J, Glasziou P, Alonso-Coello P, et al. GRADE guidelines: 11. Making an overall rating of confidence in effect estimates for a single outcome and for all outcomes. Journal of Clinical Epidemiology 2013;66(2):151-7.

Guyatt GH, Ebrahim S, Alonso-Coello P, Johnston BC, Mathioudakis AG, Briel M, et al. GRADE guidelines 17: assessing the risk of bias associated with missing participant outcome data in a body of evidence. Journal of Clinical Epidemiology 2017;87:14-22.

Guyatt GH, Oxman AD, Kunz R, Atkins D, Brozek J, Vist G, et al. GRADE guidelines: 2. Framing the question and deciding on important outcomes. Journal of Clinical Epidemiology 2011;64(4):395-400.

Guyatt GH, Oxman AD, Kunz R, Brozek J, Alonso-Coello P, Rind D, et al. GRADE guidelines 6. Rating the quality of evidence--imprecision. Journal of Clinical Epidemiology 2011;64(12):1283-93.

Guyatt GH, Oxman AD, Kunz R, Woodcock J, Brozek J, Helfand M, et al. GRADE guidelines: 7. Rating the quality of evidence--inconsistency. Journal of Clinical Epidemiology 2011;64(12):1294-302.

Guyatt GH, Oxman AD, Kunz R, Woodcock J, Brozek J, Helfand M, et al. GRADE guidelines: 8. Rating the quality of evidence--indirectness. Journal of Clinical Epidemiology 2011;64(12):1303-10.

Guyatt GH, Oxman AD, Montori V, Vist G, Kunz R, Brozek J, et al. GRADE guidelines: 5. Rating the quality of evidence--publication bias. Journal of Clinical Epidemiology 2011;64(12):1277-82.

Guyatt GH, Oxman AD, Santesso N, Helfand M, Vist G, Kunz R, et al. GRADE guidelines: 12. Preparing summary of findings tables-binary outcomes. Journal of Clinical Epidemiology 2013;66(2):158-72.

Guyatt GH, Oxman AD, Sultan S, Glasziou P, Akl EA, Alonso-Coello P, et al. GRADE guidelines: 9. Rating up the quality of evidence. Journal of Clinical Epidemiology 2011;64(12):1311-6.

Guyatt GH, Oxman AD, Vist G, Kunz R, Brozek J, Alonso-Coello P, et al. GRADE guidelines: 4. Rating the quality of evidence--study limitations (risk of bias). Journal of Clinical Epidemiology 2011;64(4):407-15.

Guyatt GH, Thorlund K, Oxman AD, Walter SD, Patrick D, Furukawa TA, et al. GRADE guidelines: 13. Preparing summary of findings tables and evidence profiles-continuous outcomes. Journal of Clinical Epidemiology 2013;66(2):173-83.

Core outcomes for chronic hepatitis B (CHB) virus infection

Critical outcomes

  • All-cause mortality or hepatitis B-related morbidity (number of participants who developed cirrhosis, ascites, variceal bleeding, hepato-renal syndrome, hepatocellular carcinoma, or hepatic encephalopathy and who have not died). These outcomes will be tested as a composite outcome as well as individually (mortality or morbidity). Such composite outcomes need to be interpreted with caution, especially if the components are influenced differently by the intervention.
  • Health-related quality of life (any valid assessment scale, filled out by the participant).
  • Serious adverse events, that is, any untoward medical occurrence that results in death, is life threatening, requires hospitalisation or prolongation of existing hospitalisation, results in persistent or significant disability or incapacity, or is a congenital anomaly or birth defect (The International Conference on Harmonization (ICH) Guidelines for Good Clinical Practice (ICH_GCP 1997)).

Important outcomes

  • Mortality due to hepatitis B-related liver disease.
  • Proportion of people with adverse events considered nonserious (any untoward medical occurrence in a participant or clinical investigation participant, that does not meet the above criteria for a serious adverse event, is defined as a non-serious adverse effect).
  • Proportion of people without histological improvement.
  • Proportion of people with detectable HBV-DNA in serum or plasma.
  • Proportion of people with detectable HBsAg in serum or plasma.
  • Proportion of people with detectable HBeAg in serum or plasma (this outcome is only relevant for HBeAg-positive participants). 
  • Proportion of people without HBeAg seroconversion in serum or plasma (this outcome is only relevant for HBeAg-positive participants). 
  • Proportion of people without normalisation of transaminases (i.e. biochemical response).

References:

International Conference on Harmonisation Expert Working Group. International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. ICH Harmonised Tripartite Guideline. Guideline for Good Clinical Practice CFR & ICH Guidelines. Vol. 1. Philadelphia (PA): Barnett International/PAREXEL, 1997.

Core outcomes for chronic hepatitis C virus infection

Critical outcomes

  • All-cause mortality or hepatitis C-related morbidity (number of participants who developed cirrhosis, ascites, variceal bleeding, hepato-renal syndrome, hepatocellular carcinoma, or hepatic encephalopathy and who have not died). These outcomes will be tested as a composite outcome as well as individually (mortality or morbidity). Such composite outcomes need to be interpreted with caution, especially if the components are influenced differently by the intervention.
  • Health-related quality of life (any valid assessment scale, filled out by the participant).  
  • Serious adverse events, that is, any untoward medical occurrence that results in death, is life threatening, requires hospitalisation or prolongation of existing hospitalisation, results in persistent or significant disability or incapacity, or is a congenital anomaly or birth defect (The International Conference on Harmonization (ICH) Guidelines for Good Clinical Practice (ICH-GCP 1997)).

Important outcomes

  • Mortality due to hepatitis C-related liver disease.
  • Non-serious adverse events. Any untoward medical occurrence in a participant or clinical investigation participant that does not meet the above criteria for a serious adverse event is defined as a non-serious adverse events.
  • Number of participants without histological improvement.
  • Failure of virological response: number of participants without sustained virological response, i.e., number of participants with detectable hepatitis C virus RNA (i.e., above lower limit of detection) in the serum by a sensitive PCR-based essay or by a transcription-mediated amplification testing 12 and 24 weeks after end of treatment.

The below outcome can also be considered:

  • Number of participants without normalisation of transaminases.

References:

International Conference on Harmonisation Expert Working Group. International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. ICH Harmonised Tripartite Guideline. Guideline for Good Clinical Practice CFR & ICH Guidelines. Vol. 1. Philadelphia (PA): Barnett International/PAREXEL, 1997.

Information on core outcome sets can be found on www.comet-initiative.org/