A theory-led framework to strengthen the focus on socio-economic inequalities in health within systematic reviews

Maden, M; McMahon, N; Booth, A; Dickson, R; Paisley, S; Gabbay, M; (2018) Toward a theory-led metaframework for considering socioeconomic health inequalities within systematic reviews; Journal of Clinical Epidemiology, 104; pp84-94; DOI:https://doi.org/10.1016/j.jclinepi.2018.08.008

Main text

This case study describes the development of a framework that can be used to develop equity sensitive programme theories that in turn will shape the design and conduct of systematic reviews resulting in findings that have greater potential to influence action to reduce socio- inequalities in health.

The authors of this paper start from the premise that all systematic reviews should consider whether the findings have potential to inform action on health inequalities.   The theoretical framework they developed can help reviewers to do this from the initial stages of developing the protocol albeit that the focus is restricted to potential for differential impacts across socio-economic groups.

The methods used to develop the framework involved ‘meta-framework’ development. This involved identifying common and unique themes from two theoretical perspectives: how socio-economic health inequalities can impact on the impact of interventions and the nature of complexity in reviews of complex intervention.   These themes were then combined into a single framework highlighting the factors and mechanisms associated with an intervention pathway that may lead to differential effects across socioeconomic groups.

The component parts of the framework relate to:

  1. What factors associated with the interview, implementation, context and individual responses may lead to differential impacts across socio-economic groups
  2. Why these factors interact to trigger change (e.g. the mechanisms through which these factors may operate – e.g. differential ability to find, engage and/or pay for a service).
  3. How these factors influence differential outcomes (e.g. by reducing exposure or risk, increasing access and affordability, etc)
  4. The impact on socio-economic inequalities in health (decrease, no impact, increase).

The authors argue that their framework enhances existing guidance that aims to strengthen the equity focus in systematic reviews by providing a practical explicit approach through which reviewers identify potential factors and mechanisms that may contribute to differential impacts. These can be integrated into a programme theory to inform the design of the systematic review and encourage greater engagement with theory throughout the review.