Beyond PROGRESS-Plus: Enhancing Methodologies for Health Equity in Systematic Reviews

A study found that the PROGRESS-Plus framework is widely used to assess health equity impacts in public health interventions, but it often faces challenges due to data limitations and complex interactions between equity dimensions. The study calls for more comprehensive methodologies and clearer justifications in systematic reviews.

In a study recently published in the Journal of Clinical Epidemiology, researchers examined the methods used to assess the health equity impacts of public health interventions through systematic reviews. The primary focus of the research was to explore how various frameworks and tools, particularly PROGRESS-Plus, are applied to investigate disparities in health outcomes across different sociodemographic dimensions. Health equity, a critical concern in public health, refers to the systematic, socially produced, and unfair disparities in health outcomes between different population subgroups. These disparities are often linked to characteristics such as socioeconomic status, gender, race, and place of residence, among others. Understanding and addressing these inequities is essential for improving public health outcomes on a broader scale.

PROGRESS-Plus: A Predominant Framework in Health Equity Research

The study involved an extensive analysis of 120 systematic reviews, selected from a pool of 322 full-text reports that were screened for eligibility. These reviews were drawn from various sources, including the Cochrane Database of Systematic Reviews and other specialized databases focusing on health equity. The authors aimed to identify how methods, frameworks, and tools are used to conceptualize dimensions of health equity in these reviews and to document the challenges and opportunities encountered in their application. PROGRESS-Plus emerged as the predominant framework used in these reviews. This framework, endorsed by the Campbell and Cochrane Equity Methods Group, is designed to guide the assessment of health inequities by focusing on specific sociodemographic characteristics. These characteristics include place of residence, race/ethnicity, occupation, gender/sex, religion, education, socioeconomic status, and social capital, among others. The framework also includes a "Plus" component, which covers additional dimensions such as personal characteristics, features of relationships, and time-dependent circumstances.

Data Limitations and Incomplete Applications

Despite its widespread use, the study found that PROGRESS-Plus is often challenging to apply fully in systematic reviews due to limitations in the available data. Many primary studies included in these reviews do not report the necessary information needed to assess differential impacts fully. This lack of data often results in reviews being unable to apply the intended methods to their full extent, leading to incomplete or partial analyses. Moreover, while most reviews included a general rationale for focusing on equity impacts, few provided explicit justifications for their focus on specific dimensions of equity. This lack of specificity raises concerns about the thoroughness and clarity of these investigations, as it leaves readers unable to determine whether the focus on certain dimensions is justified.

The Challenge of Standardizing Measurements

The study also highlights several significant measurement and conceptual challenges associated with using PROGRESS-Plus and similar frameworks. One of the key challenges is the lack of standardized definitions and measurements for the various constructs related to equity, such as socioeconomic status. The study found that these constructs are often reported in widely varying ways across different primary studies, leading to inconsistencies in how they are treated within systematic reviews. For example, some reviews opted to generate simpler composite outcomes to integrate a wider range of reported constructs and measures, while others addressed the multidimensional nature of constructs like socioeconomic status by considering their constituent parts separately. These inconsistencies can make it difficult to compare findings across studies and may limit the explanatory power of the reviews.

Complex Interactions in Health Inequities

Another challenge identified by the study is the complex and contextual nature of differential impacts. The dimensions of equity impacts often interact with one another, as well as with broader temporal, personal, social, or geographic contexts. This complexity makes it difficult to assume that the impacts observed in different studies are comparable, even when they have been measured in similar ways. The study suggests that while PROGRESS-Plus is sufficiently broad to encompass the dimensions of equity typically examined in systematic reviews, it does not necessarily ensure or guide critical thinking about more complex pathways or interactions between these dimensions. The framework's ability to address these complexities is limited, and the study calls for more explicitly rationalized and considered approaches to the design, conduct, and reporting of both primary research and systematic reviews.

Toward More Comprehensive Methodologies

To improve the utility of systematic reviews in assessing health equity impacts, the study advocates for several methodological advancements. These include the development of more consistent and coherent methods for conceptualizing and measuring dimensions of equity, as well as the adoption of more comprehensive frameworks that can better account for the complex and intersectional nature of health disparities. The authors also emphasize the need for more detailed and transparent reporting of equity considerations in systematic reviews, including clear justifications for the focus on specific dimensions of equity. Ultimately, the study concludes that while PROGRESS-Plus is a valuable tool for guiding investigations of health equity impacts, it is not sufficient on its own to address the full range of challenges associated with this complex and critical area of public health research. More comprehensive and nuanced approaches are needed to ensure that systematic reviews can effectively inform policy and practice in ways that reduce health inequities and promote social justice in public health.