Skip to content

When you choose to publish with PLOS, your research makes an impact. Make your work accessible to all, without restrictions, and accelerate scientific discovery with options like preprints and published peer review that make your work more Open.

PLOS BLOGS Speaking of Medicine and Health

Reporting guidelines for systematic reviews that consider effects on health equity

We would like to invite readers of Speaking of Medicine to complete a survey about which items should be reported in equity-oriented systematic reviews.   The survey is available at:

After an initial survey, we will summarize comments and feedback, and send the survey for a second round of feedback including the ranking of importance of the items.

Health inequities are differences in health which are both avoidable and considered unfair or unjust [1].  Between-country and within-country health inequity persists despite local, national and international initiatives to redress them such as the 2008 Marmot review in the UK, the WHO Commission on Social Determinants of Health.  For example, despite progress towards the Millennium Development Goals, within-country inequality in under-5 mortality increased in as many countries as it decreased  [2].  Systematic reviews have been called for to compile the evidence on how to reduce inequalities [3].

Systematic reviews are increasingly promoted as a tool to inform decision-making, evidenced by the Mexico Statement in 2004 (WHA 58.10), the final report of the Measurement and Evidence Knowledge Network of the WHO Commission on Social Determinants of Health [4] and the Montreux Health Systems Conference (2010).

Systematic reviews which focus on average effects can hide differences between groups, such as effects of interventions in vulnerable or poor populations.  The Campbell and Cochrane Equity group uses the acronym PROGRESS-Plus to define factors across which differences in effects may relate to health equity: Place of residence (rural/urban/inner city, low- or middle-income country), Race/ethnicity/culture, Occupation, Gender/sex, Religion, Education (literacy), Socioeconomic status, and Social capital, while “Plus” refers to other categories across which discrimination may exist such as sexual orientation, age, disability, or disease status [5].  Other criteria have also been used to identify factors across which differences in effects are important [6;7].  Systematic reviews can assess effects in vulnerable populations  using one of three methods outlined in BOX 1. Based on a random sample of systematic reviews in 2004, we estimate that approximately 25% of systematic reviews indexed in MEDLINE meet one or more of these criteria as equity-oriented systematic reviews [8;9].

The Campbell and Cochrane Equity Methods Group was convened in 2006 to develop and evaluate methods to assess effects on health inequity in equity-oriented systematic reviews [10].  In 2010, members of this team (PT, MP, VW) and members of the CSDH Measurement and Evidence Network published guidance on seven features of systematic reviews that may need modifying in order to provide better answer to questions about health inequity [11].  We recently assessed the methods used by systematic reviews to assess effects in vulnerable populations in a Cochrane methodology systematic review [8].  and  identified deficiencies in reporting including insufficient reporting of methods for analyses (e.g. subgroup analyses) and lack of transparency in judgments about applicability to disadvantaged settings [8].   Individual studies included in this review identified lack of clarity of reporting of analyses relevant to specific factors, such as sex and gender [12], low and middle income countries [13] and people of low socioeconomic status [14].  Policy-makers have also cited the lack of consideration of health equity as a barrier to using systematic review for evidence-informed decision-making [15;16].

One way to improve reporting of facets of specific importance to SRs reporting on inequities is to develop specific reporting guidelines [17], for example, by revising the PRISMA statement. The PRISMA statement contains 26 items,  and the aim of PRISMA is to encourage transparency of reporting of the methods of SRs [18]. Currently PRISMA has no guidance specific to health equity and we are now in the process of developing an extension to PRISMA specifically for equity SRs.

To produce a PRISMA equity extension we are following the methods recommended by Moher et al [17] to develop health research reporting guidelines. In the first phase, we conducted a pilot study (PT, MP, VW, DM), held preliminary meetings to discuss these items and compared PRISMA items with empiric evidence about equity-oriented systematic reviews.  From this we identified a preliminary set of 14 characteristics of equity-oriented reviews that may require modification of existing items in PRISMA or the addition of new items.

These steps include the identifying the need for the guidance, obtaining funding, identifying participants for a consensus meeting, conducting a Delphi exercise to gather broad feedback and opinions prior to the consensus meeting, holding a face to face consensus meeting to discuss background empiric evidence and survey results, developing the guidance statement and elaboration documents and developing and implementing a knowledge translation strategy.  The knowledge translation strategy includes developing methods to encourage feedback and criticism as well as promoting endorsement and adherence to the guideline by journals, funders, organizations and individuals.

The next step is to consult widely using a two-round Delphi survey to find out what a broad range of authors and readers of SRs thinks we should include in the PRISMA equity extension. We have therefore invited you to complete a survey which is available at:

Once the initial survey is complete, we will summarize comments and feedback, and send the survey for a second round of feedback including the ranking of importance of the items.


We are grateful to the Rockefeller Foundation for providing accommodation at their Bellagio Sfrondata conference centre and to the Canadian Institutes of Health Research for funding travel for participants.

Vivian Welch, David Moher, Mark Petticrew, Peter Tugwell

Reference List

(1)   Whitehead M. The Concepts and Principles of Equity and Health. International Journal of Health Services 1992;22:429-45.

(2)   Moser KA, Leon DA, Gwatkin DR. How does progress towards the child mortality millennium development goal affect inequalities between the poorest and least poor? Analysis of Demographic and Health Survey data. BMJ 2005;331:1180-2.

(3)   Mackenbach JP. Tackling inequalities in health: the need for building a systematic evidence base. Journal of Epidemiology & Community Health 2003;57:162.

(4)   Kelly MP, Morgan A, Bonnefoy J, Butt J, Bergman V, Mackenbach JP, et al. The social determinants of health: Developing an evidence base for political action. Geneva: World Health Organisation; 2007.

(5)   Evans T, Brown H. Road traffic crashes: operationalizing equity in the context of health sector reform. Injury Control & Safety Promotion 2003;10:11-2.

(6)   Oxman AD, Lavis JN, Lewin S, et al. SUPPORT Tools for evidence-informed health Policymaking (STP) 10: Taking equity into consideration when assessing the findings of a systematic review. Health Research Policy & Systems 2009;7:Suppl.

(7)   Dans AL, Dans LF, Guyatt GH. Applying results to individual patients. In: Guyatt GH, Rennie D, Meade MO, Coon JT, editors. Part B Therapy. 2 ed. New York: McGraw-Hill Companies; 2008. p. 273-89.

(8)   Welch V, Smylie JK, Kristjansson E, Brand K, Tugwell P, Wells GA. What is the role of systematic reviews in tackling health inequity? University of Ottawa; 2010.

(9)   Tsikata S, Robinson V, Petticrew M, Kristjansson E, Moher D, McGowan J, et al. Is health equity considered in systematic reviews of the Cochrane Collaboration? Barcelona, Spain 2003.

(10)   Tugwell P, Petticrew M, Robinson V, et al. Cochrane and Campbell Collaborations, and health equity. Lancet 2006;367:1128-30.

(11)   Tugwell P, Petticrew M, Kristjansson E, et al. Assessing equity in systematic reviews: realising the recommendations of the Commission on Social Determinants of Health. BMJ 2010;341:c4739.

(12)   Doull M, Runnels VE, Tudiver S, et al. Appraising the evidence: applying sex- and gender-based analysis (SGBA) to Cochrane systematic reviews on cardiovascular diseases. [Review] [53 refs]. Journal of Women’s Health 2010;19:997-1003.

(13)   Chopra M, Munro S, Lavis JN, et al. Effects of policy options for human resources for health: an analysis of systematic reviews. Lancet 2008;371:668-774.

(14)   Ball P, Stahlman R, Kubin R, et al. Safety profile of oral and intravenous moxifloxacin: cumulative data from clinical trials and postmarketing studies. Clin Ther 2004;26:940-50.

(15)   Petticrew M, Whitehead M, Macintye SJ, et al. Evidence for public health policy on inequalities: 1: the reality according to policymakers. J Epidemiol Community Health 2004;58:811-6.

(16)   Lavis JN, Davies HTO, Gruen RL. Working within and beyond the Cochrane Collaboration to make systematic reviews more useful to healthcare managers and policy makers. Healthcare Policy 2006;1:21-33.

(17)   Moher D, Schulz KF, Simera I, et al. Guidance for Developers of Health Research Reporting Guidelines. PLoS Med 2010;7:e1000217.

(18)   Moher D, Liberati A, Tetzlaff J, et al. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. BMJ 2009;339.


Leave a Reply

Your email address will not be published. Required fields are marked *

Add your ORCID here. (e.g. 0000-0002-7299-680X)

Back to top