Health in all countries of the world is unevenly and, to some extent, unfairly distributed according to socioeconomic position. Health and longevity are highest for the richest, and decrease steadily with decreasing socioeconomic status. Avoidable and unfair inequalities have been termed health inequities. Enhancing health equity has now achieved international political importance with endorsement from the World Health Assembly in 2009. The failure of systematic reviews to consider effects on health equity is cited by decision-makers as a limitation. Hence, there is a need for guidance on the advantages and disadvantages of how to assess effects on health equity in systematic reviews.
This review identified thirty-four methodological studies in which collections of systematic reviews were examined. We identified four methodological approaches to assess the effects on health equity, a descriptive assessment in the reviews, a descriptive assessment of the trials included in the reviews, analytic approaches, and applicability assessment. However, the most appropriate way to address any of these approaches is unclear. There is a need for methodological guidance on how to assess effects on health equity in systematic reviews. Analysis of particular groups of populations need to be justified and reported in sufficient detail to allow their credibility to be assessed. There is a need for improved transparency of judgments about applicability and relevance to disadvantaged populations.