Editorial
‘It is surely a great criticism of our profession…’ The next 20 years of equity-focused systematic reviews M Petticrew,1,2,3 V Welch,3 P Tugwell4,5,6 The Cochrane Collaboration has been celebrating 20 years of its existence throughout 2013. For 20 years it has aimed to support policymakers, practitioners and patients in making betterinformed decisions about healthcare and public health. Founded in 1993, it remains the largest global network of scientists, researchers, health policymakers and consumer advocates involved in the production of systematic reviews of healthcare evidence. For those involved in public health decision making, health equity continues to be a pivotal concern. Systematic reviews like those produced by Cochrane help identify potentially effective interventions, as well as identifying interventions that risk increasing inequity as an unintended consequence.1 2 Much relevant evidence on social determinants of health inequity now derives from systematic reviews, though in general there is not much of an equity perspective in clinical and public health research, although this is changing. The Cochrane and Campbell Equity Methods Group was set up to address this gap as well as to develop methods and improve reporting. This group has led initiatives to systematically consider equity in priority setting3 4 and to define personal and population characteristics across which equity might be important using the PROGRESS framework (Place of residence, Race/ethnicity/ language/culture; Occupation, Gender/sex, Religion, Occupation, Socioeconomic status and social capital).5 However, these are initial steps and there are many remaining priorities for the next 20 years. On the equity front
1
Bruyere Research Institute, University of Ottawa, Canada; 2Ottawa Hospital Research Institute, University of Ottawa, Canada; 3Institute of Population Health, University of Ottawa, Ottawa, Ontario, Canada; 4 Departments of Medicine, University of Ottawa, Ottawa, Ontario, Canada; 5Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; 6 Ottawa Hospital Research Institute, Clinical Epidemiology Program, Ottawa, Ontario, Canada Correspondence to Dr Mark Petticrew, Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, 15-17 Tavistock Sq, London WC1H 9SH, UK; [email protected]
there is a need to routinely incorporate an equity focus, and not just within the Cochrane Collaboration; many systematic reviews are conducted outside of Cochrane, particularly those that are not focused on effectiveness. Equity could be a key consideration for many of those reviews. Indeed, as many other scientific fields have taken up systematic review methods, (eg, climate science, international development, environmental science and others), we may see the much wider adoption of an equity perspective beyond public health and healthcare. One methodological challenge is that systematic reviews need to continue to strive to incorporate more complex sets of evidence if they are to be credible and useful to users. This is particularly important when reviewing complex interventions. The day of the systematic review of a few selected intervention studies, with the non-committal conclusion that ‘more evidence is needed’, surely is (or should be) drawing to a close. Reviewing evidence on equity in particular requires methodological flexibility because the determinants of inequalities are upstream and lie in the living and working conditions. The relevant evidence, therefore, often derives from non-randomised and mixed-methods studies. The further development of meta-analytic and narrative methods for integrating non-randomised controlled trials (non-RCT) evidence will therefore remain a priority. On a related issue, Archie Cochrane noted disapprovingly, “Observational evidence is clearly better than opinion, but it is thoroughly unsatisfactory”. This may be true for some interventions, but in public health it is undeniable that there is a considerable body of adequate and reliable evidence that is observational in nature. There are also significant nonmethodological challenges in the field of equity. One is that reviewers need to challenge the assumption that public health solutions should focus on lifestyles and individual ‘choices’. It is an enduring problem that when ‘health inequalities’ and interventions are considered, at least in developed countries, the remedies seem to be to focus on ‘unhealthy lifestyles’. Yet
Petticrew M, et al. J Epidemiol Community Health April 2014 Vol 68 No 4
health inequities are not the simple outcome of poor lifestyle ‘choices’ among the poor, and the solution is not only to address health behaviours—such as smoking, diet, physical activity and alcohol consumption—but to intervene in the conditions that support and create unhealthy behaviours in the first place. ‘Poor’ lifestyle choices are constrained by upstream influences—including social and welfare and educational policies, fiscal policies, as well as being influenced by the decisions of large industries—including the tobacco, food, alcohol and other industries. Systematic reviews can shed light on all these influences—and systematic reviews of intervention studies are only part of the remedy. Such reviews may even be harmful on occasion, as they can draw the policymaker’s eye towards simpler, downstream solutions. This is because the interventions that tend to be evaluated in primary studies, and that then become incorporated into the reviews, are much more likely to be behavioural and individually focused. Such downstream solutions then provide a fig leaf for those wider upstream influences. The problem may be addressed by ensuring that reviews address both downstream and upstream solutions together— for example, in the case of obesity, addressing both the school food supply and the school environment,6 or focusing upstream—as in a recent review of larvicidal management of malaria.7 Systematic reviews might therefore more frequently consider the role of political and commercial influences on health and health inequalities as part of the context within which health behaviours take place and within which interventions are delivered. Such systematic reviews that explore the relationships between living conditions (including political conditions) and health and health-related outcomes play an important role and can identify policy leverage points in which to intervene in a system.8 A final ongoing challenge—one that hopefully will not take another 20 years to address—is that there are still many myths that linger around Cochrane and systematic reviews. One of the more enduring ones is that Cochrane is mainly concerned with medical interventions, and with RCTs alone. Neither is true, and the first review that the equity group produced included a wide range of randomised and nonrandomised evidence to explore processes and outcomes together.9 10 Another myth is that Cochrane reviews are inimical to the nuanced question of ‘what works, for whom, and in what circumstances’—as 291
Editorial opposed to simply dividing the known world into things that ‘work’ or ‘don’t work’. The question of ‘what works, for whom, and in what circumstances’ is a key one for equity reviews because their very purpose is to identify not the overall population-level effects but to explore the distribution of those effects. To help this, the Equity group is encouraging the use of the PROGRESS acronym (defined above) to consider distribution of effects.5 4 Archie Cochrane famously issued the challenge in 1979: “It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials.” For public health reviewers, and those with an interest in equity, it would surely be an even greater criticism if those reviewers did not increasingly turn their attention to the observational and qualitative evidence that is often overlooked. It is this evidence that makes up most of the relevant evidence base and that can help identify and shape responses to the upstream influences on health and health inequalities.
292
Contributors MP wrote the first draft. VW and PT reviewed and revised the subsequent and final drafts. Competing interests The authors are co-ordinators of the Campbell & Cochrane Equity Methods Group.
4
Provenance and peer review Commissioned; internally peer reviewed. 5
To cite Petticrew M, Welch V, Tugwell P. J Epidemiol Community Health 2014;68:291–292.
6
Received 17 September 2013 Accepted 22 October 2013 Published Online First 27 November 2013
7
J Epidemiol Community Health 2014;68:291–292. doi:10.1136/jech-2013-203400
8
REFERENCES 1
2
3
Lorenc T, Petticrew M, Welch V, et al. What types of interventions generate inequalities? Evidence from systematic reviews. J Epidemiol Community Health 2013;67:190–3. White M, Adams J, Heywood P. How and why do interventions that increase health overall widen inequalities within populations? In: Babones S. ed. Health, inequality and society. Bristol: Policy Press, 2009. Nasser M, Ueffing E, Welch V, et al. An equity lens can ensure an equity-oriented approach to agenda
9
10
setting and priority setting of Cochrane Reviews. J Clin Epidemiol 2013;66:511–21. Welch V, Petticrew M, Tugwell P, et al. PRISMA-equity 2012 extension: reporting guidelines for systematic reviews with a focus on health equity. PLoS Med 2012;9:e1001333. doi:10.1371/journal.pmed. 1001333 2012 O’Neill J, Tabish H, Welch V, et al. Applying an Equity Lens to interventions: Using PROGRESS to ensure consideration of socially stratifying factors to illuminate inequities in health. J Clin Epidemiol Available online 1 November 2013; http://dx.doi.org/10.1016/j. jclinepi.2013.08.005 Waters E, de Silva-Sanigorski A, Burford B, et al. Interventions for preventing obesity in children. Cochrane Database Syst Rev 2011;(12):CD001871. Tusting L, Thwing J, Sinclair D, et al. Mosquito larval source management for controlling malaria. Cochrane Database Syst Rev 2013;(8):CD008923. Whitehead M, Dahlgren G. Concepts and principles for tackling social inequities in health: levelling up: Part 1. WHO Collaborating Centre for Policy Research on Social Determinants of Health, University of Liverpool, 2007. http://www.euro.who.int/__data/ assets/pdf_file/0010/74737/E89383.pdf (accessed 26 May 2011). Greenhalgh T, Kristjansson E, Robinson V. Realist review to understand the efficacy of school feeding programmes. Br Med J 2007;335:858. Kristjansson E, Robinson V, Petticrew M, et al. School feeding for improving the physical and psychosocial health of disadvantaged elementary school children. Cochrane Database Syst Rev 2007; (1):CD004676.
Petticrew M, et al. J Epidemiol Community Health April 2014 Vol 68 No 4
‘It is surely a great criticism of our profession…’ The next 20 years of equity-focused systematic reviews M Petticrew,1,2,3 V Welch,3 P Tugwell4,5,6 The Cochrane Collaboration has been celebrating 20 years of its existence throughout 2013. For 20 years it has aimed to support policymakers, practitioners and patients in making betterinformed decisions about healthcare and public health. Founded in 1993, it remains the largest global network of scientists, researchers, health policymakers and consumer advocates involved in the production of systematic reviews of healthcare evidence. For those involved in public health decision making, health equity continues to be a pivotal concern. Systematic reviews like those produced by Cochrane help identify potentially effective interventions, as well as identifying interventions that risk increasing inequity as an unintended consequence.1 2 Much relevant evidence on social determinants of health inequity now derives from systematic reviews, though in general there is not much of an equity perspective in clinical and public health research, although this is changing. The Cochrane and Campbell Equity Methods Group was set up to address this gap as well as to develop methods and improve reporting. This group has led initiatives to systematically consider equity in priority setting3 4 and to define personal and population characteristics across which equity might be important using the PROGRESS framework (Place of residence, Race/ethnicity/ language/culture; Occupation, Gender/sex, Religion, Occupation, Socioeconomic status and social capital).5 However, these are initial steps and there are many remaining priorities for the next 20 years. On the equity front
1
Bruyere Research Institute, University of Ottawa, Canada; 2Ottawa Hospital Research Institute, University of Ottawa, Canada; 3Institute of Population Health, University of Ottawa, Ottawa, Ontario, Canada; 4 Departments of Medicine, University of Ottawa, Ottawa, Ontario, Canada; 5Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada; 6 Ottawa Hospital Research Institute, Clinical Epidemiology Program, Ottawa, Ontario, Canada Correspondence to Dr Mark Petticrew, Faculty of Public Health and Policy, London School of Hygiene and Tropical Medicine, 15-17 Tavistock Sq, London WC1H 9SH, UK; [email protected]
there is a need to routinely incorporate an equity focus, and not just within the Cochrane Collaboration; many systematic reviews are conducted outside of Cochrane, particularly those that are not focused on effectiveness. Equity could be a key consideration for many of those reviews. Indeed, as many other scientific fields have taken up systematic review methods, (eg, climate science, international development, environmental science and others), we may see the much wider adoption of an equity perspective beyond public health and healthcare. One methodological challenge is that systematic reviews need to continue to strive to incorporate more complex sets of evidence if they are to be credible and useful to users. This is particularly important when reviewing complex interventions. The day of the systematic review of a few selected intervention studies, with the non-committal conclusion that ‘more evidence is needed’, surely is (or should be) drawing to a close. Reviewing evidence on equity in particular requires methodological flexibility because the determinants of inequalities are upstream and lie in the living and working conditions. The relevant evidence, therefore, often derives from non-randomised and mixed-methods studies. The further development of meta-analytic and narrative methods for integrating non-randomised controlled trials (non-RCT) evidence will therefore remain a priority. On a related issue, Archie Cochrane noted disapprovingly, “Observational evidence is clearly better than opinion, but it is thoroughly unsatisfactory”. This may be true for some interventions, but in public health it is undeniable that there is a considerable body of adequate and reliable evidence that is observational in nature. There are also significant nonmethodological challenges in the field of equity. One is that reviewers need to challenge the assumption that public health solutions should focus on lifestyles and individual ‘choices’. It is an enduring problem that when ‘health inequalities’ and interventions are considered, at least in developed countries, the remedies seem to be to focus on ‘unhealthy lifestyles’. Yet
Petticrew M, et al. J Epidemiol Community Health April 2014 Vol 68 No 4
health inequities are not the simple outcome of poor lifestyle ‘choices’ among the poor, and the solution is not only to address health behaviours—such as smoking, diet, physical activity and alcohol consumption—but to intervene in the conditions that support and create unhealthy behaviours in the first place. ‘Poor’ lifestyle choices are constrained by upstream influences—including social and welfare and educational policies, fiscal policies, as well as being influenced by the decisions of large industries—including the tobacco, food, alcohol and other industries. Systematic reviews can shed light on all these influences—and systematic reviews of intervention studies are only part of the remedy. Such reviews may even be harmful on occasion, as they can draw the policymaker’s eye towards simpler, downstream solutions. This is because the interventions that tend to be evaluated in primary studies, and that then become incorporated into the reviews, are much more likely to be behavioural and individually focused. Such downstream solutions then provide a fig leaf for those wider upstream influences. The problem may be addressed by ensuring that reviews address both downstream and upstream solutions together— for example, in the case of obesity, addressing both the school food supply and the school environment,6 or focusing upstream—as in a recent review of larvicidal management of malaria.7 Systematic reviews might therefore more frequently consider the role of political and commercial influences on health and health inequalities as part of the context within which health behaviours take place and within which interventions are delivered. Such systematic reviews that explore the relationships between living conditions (including political conditions) and health and health-related outcomes play an important role and can identify policy leverage points in which to intervene in a system.8 A final ongoing challenge—one that hopefully will not take another 20 years to address—is that there are still many myths that linger around Cochrane and systematic reviews. One of the more enduring ones is that Cochrane is mainly concerned with medical interventions, and with RCTs alone. Neither is true, and the first review that the equity group produced included a wide range of randomised and nonrandomised evidence to explore processes and outcomes together.9 10 Another myth is that Cochrane reviews are inimical to the nuanced question of ‘what works, for whom, and in what circumstances’—as 291
Editorial opposed to simply dividing the known world into things that ‘work’ or ‘don’t work’. The question of ‘what works, for whom, and in what circumstances’ is a key one for equity reviews because their very purpose is to identify not the overall population-level effects but to explore the distribution of those effects. To help this, the Equity group is encouraging the use of the PROGRESS acronym (defined above) to consider distribution of effects.5 4 Archie Cochrane famously issued the challenge in 1979: “It is surely a great criticism of our profession that we have not organised a critical summary, by specialty or subspecialty, adapted periodically, of all relevant randomised controlled trials.” For public health reviewers, and those with an interest in equity, it would surely be an even greater criticism if those reviewers did not increasingly turn their attention to the observational and qualitative evidence that is often overlooked. It is this evidence that makes up most of the relevant evidence base and that can help identify and shape responses to the upstream influences on health and health inequalities.
292
Contributors MP wrote the first draft. VW and PT reviewed and revised the subsequent and final drafts. Competing interests The authors are co-ordinators of the Campbell & Cochrane Equity Methods Group.
4
Provenance and peer review Commissioned; internally peer reviewed. 5
To cite Petticrew M, Welch V, Tugwell P. J Epidemiol Community Health 2014;68:291–292.
6
Received 17 September 2013 Accepted 22 October 2013 Published Online First 27 November 2013
7
J Epidemiol Community Health 2014;68:291–292. doi:10.1136/jech-2013-203400
8
REFERENCES 1
2
3
Lorenc T, Petticrew M, Welch V, et al. What types of interventions generate inequalities? Evidence from systematic reviews. J Epidemiol Community Health 2013;67:190–3. White M, Adams J, Heywood P. How and why do interventions that increase health overall widen inequalities within populations? In: Babones S. ed. Health, inequality and society. Bristol: Policy Press, 2009. Nasser M, Ueffing E, Welch V, et al. An equity lens can ensure an equity-oriented approach to agenda
9
10
setting and priority setting of Cochrane Reviews. J Clin Epidemiol 2013;66:511–21. Welch V, Petticrew M, Tugwell P, et al. PRISMA-equity 2012 extension: reporting guidelines for systematic reviews with a focus on health equity. PLoS Med 2012;9:e1001333. doi:10.1371/journal.pmed. 1001333 2012 O’Neill J, Tabish H, Welch V, et al. Applying an Equity Lens to interventions: Using PROGRESS to ensure consideration of socially stratifying factors to illuminate inequities in health. J Clin Epidemiol Available online 1 November 2013; http://dx.doi.org/10.1016/j. jclinepi.2013.08.005 Waters E, de Silva-Sanigorski A, Burford B, et al. Interventions for preventing obesity in children. Cochrane Database Syst Rev 2011;(12):CD001871. Tusting L, Thwing J, Sinclair D, et al. Mosquito larval source management for controlling malaria. Cochrane Database Syst Rev 2013;(8):CD008923. Whitehead M, Dahlgren G. Concepts and principles for tackling social inequities in health: levelling up: Part 1. WHO Collaborating Centre for Policy Research on Social Determinants of Health, University of Liverpool, 2007. http://www.euro.who.int/__data/ assets/pdf_file/0010/74737/E89383.pdf (accessed 26 May 2011). Greenhalgh T, Kristjansson E, Robinson V. Realist review to understand the efficacy of school feeding programmes. Br Med J 2007;335:858. Kristjansson E, Robinson V, Petticrew M, et al. School feeding for improving the physical and psychosocial health of disadvantaged elementary school children. Cochrane Database Syst Rev 2007; (1):CD004676.
Petticrew M, et al. J Epidemiol Community Health April 2014 Vol 68 No 4
