Vivian Welch, David Moher, Mark Petticrew, Peter Tugwell: Reporting guidelines for systematic reviews that consider effects on health equity

We would like to invite readers of BMJ Blogs to complete a survey about this proposed extension, which 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. 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, and 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. Systematic reviews have been called for to compile the evidence on how to reduce inequalities.

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, 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, religion, education, 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. Other criteria have also been used to identify factors across which differences in effects are important [1]. 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 [2].

Box 1: Examples of how systematic reviews can assess effects of interventions in vulnerable populations
Method Examples
1. Assessing the effects of interventions specifically targeted at vulnerable populations School feeding for disadvantaged childrenHome visits for disadvantaged mothers
2. Assessing the differential effects of universal programs across categories of disadvantage (e.g. across the one or more PROGRESS+ factors) Effects of workplace occupational health programs for different social classesEffects of tobacco control across socioeconomic factors
3. Answering a question that is relevant to vulnerable populations (e.g. related to diseases for which vulnerable populations carry a disproportionate burden such as neglected tropical diseases Insecticide treated bednets for preventing malaria mortalityDirectly observed therapy for tuberculosis

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.  In 2010, members of this team (Peter Tugwell, Mark Petticrew, Vivian Welch) 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. We recently assessed the methods used by systematic reviews to assess effects in vulnerable populations in a Cochrane methodology systematic review 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. Individual studies included in this review identified lack of clarity of reporting of analyses relevant to specific factors, such as sex and gender, low and middle income countries, and people of low socioeconomic status [3].  Policy-makers have also cited the lack of consideration of health equity as a barrier to using systematic review for evidence-informed decision-making.

One way to improve reporting of facets of specific importance to SRs reporting on inequities is to develop specific reporting guidelines, 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 systematic reviews. 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 systematic reviews.

To produce a PRISMA equity extension we are following the methods recommended by Moher et al 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 here. 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.

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.

We would like to invite readers of BMJ Blogs to complete a survey about this proposed extension, which 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.

(1)  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.

(2)  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.

(3)  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.

Vivian Welch, PhD, is an associate investigator at the Ottawa Hospital research Institute and deputy director of the Centre for Global Health, Institute of Population Health, University of Ottawa.  She has been involved in conducting systematic reviews in the area of musculoskeletal disease and public health for over 10 years and her research interests are in the development and application of methods for considering health equity in systematic reviews and clinical guidelines.  Dr. Welch is a member of the Campbell and Cochrane Equity Methods Group, the international Grading Recommendations Assessment, Development and Evaluation (GRADE working group), and the International Clinical Epidemiology Network (INCLEN).

David Moher, PhD, is a senior scientist at the Clinical Epidemiology Program, Ottawa Hospital Research Institute, and Associate Professor, Department o Epidemiology and Community Medicine, University of Ottawa. Dr. Moher has been involved in systematic reviews for more than 20 years. He has made contributions to the conduct and reporting of systematic reviews. He is the senior author of the PRISMA Statement, a guideline for reporting systematic reviews. Dr. Moher is associated with many journals, is a member of the advisory board for the International Congress on Peer Review and Biomedical Publication, and a member of the EQUATOR Network’s steering group.

Mark Petticrew, BA, PhD, is professor of public health evaluation in the Department of Social and Environmental Health Research in the Faculty of Public Health and Policy at London School of Hygiene and Tropical Medicine. His research has involved primary research on the health effects of housing, urban regeneration, transport and employment interventions. He has also worked on systematic reviews of the effects on health and health inequalities of employment, housing, transport and tobacco control policies. He is one of the convenors of the Cochrane/Campbell Health Equity Group, and is an editor of the Cochrane Public Health Review Group.

Peter Tugwell, MD, MSc, FRCPC, is professor of medicine, and epidemiology and community medicine at the University of Ottawa. He holds the Canada Research Chair in Health Equity. He is a staff physician and practicing rheumatologist at the Ottawa Hospital, Ottawa, Canada. The goal of Dr. Tugwell’s equity research program is to improve the health status of the poor and middle class and reduce socioeconomic inequalities in health, through facilitating the summarising and dissemination of systematic reviews of educational, health, legal and social strategies to reduce inequitable inequalities in health in individuals and populations. Dr. Tugwell received his medical degree from the Royal Free Hospital Medical School at London University. Subsequently, Dr. Tugwell has worked in London, Ahmadu Bello University in Zaria in Nigeria, McMaster University in Hamilton, and the University of Ottawa.