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Introduction

Clinical preventive services play an essential role in decreasing death and disability and improving the health of the nation. Preventive services such as breast cancer screenings, counseling on tobacco cessation, and preventive medication to decrease risk of HIV infection help to prevent certain diseases and, in some cases, enable early detection and treatment. The Patient Protection and Affordable Care Act (ACA), signed into law in 2010, required health plans to cover 100 percent of preventive services without charging patients for coinsurance, copayments, or deductibles. These services are identified as those that “provide coverage for a range of preventive services and may not impose cost-sharing” on patients receiving the services (KFF, 2015). Preventive services that are recommended by the U.S. Preventive Services Task Force (USPSTF), the Advisory Committee on Immunization Practices, the Health Resources and Services Administration (HRSA) (including HRSA’s Bright Futures Project), and the Institute of Medicine’s Committee on Women’s Clinical Preventive Services are all required to be covered at no cost to patients (HRSA, 2020).

The USPSTF has issued clinical practice guidelines (CPGs) since 1989, recommending for or against clinical preventive services, including screenings, behavioral counseling, and preventive medication. In addition to providing recommendations for or against the use of specific interventions, the USPSTF highlights current gaps in the evidence base for a particular topic. They do so in recommendation statements as well as I statements, which are issued for preventive services about which there is insufficient evidence to issue a recommendation. The USPSTF

have included evidence gaps since the first edition of its Clinical Guide was published. However, there have been limited efforts to systematize the identification of evidence gaps in prevention research, resulting in limited information about the impact such work has had on the research field as a whole. There is also limited evidence regarding the impact of the USPSTF’s evidence gap identification in catalyzing prevention research agendas and studies that will enable a topic to be reviewed and updated. The purpose of this report is to (1) review the recommendation statements in the USPSTF portfolio and outline how evidence gaps are described; (2) suggest a taxonomy of evidence gaps and research needs for use in prevention research; (3) discuss novel research methodology that is needed to inform evidence gaps; and (4) propose new opportunities for collaboration among prevention researchers, funders, and guideline developers to accelerate prevention research that will close priority evidence gaps.

STATEMENT OF TASK

In an effort to close evidence gaps in clinical prevention, the Agency for Healthcare Research and Quality (AHRQ) and the National Institutes of Health’s (NIH’s) Office of Disease Prevention (ODP) contracted with the National Academies of Sciences, Engineering, and Medicine to convene an ad hoc committee to evaluate evidence gaps described by the USPSTF and other CPG developers and create a taxonomy of the evidence gaps that the USPSTF and other CPG developers could use in future recommendations. Furthermore, the committee was asked to provide methods for prevention research funders and recommendation statement developers, including but not limited to NIH and the USPSTF, to improve their partnerships to accelerate research to close important gaps in prevention (see Box 1-1 for the complete Statement of Task).

At the committee’s first meeting, David Murray, director of ODP, characterized the challenges in addressing evidence gaps in two ways: nonspecific descriptions (e.g., “high-quality studies on the potential harms of screening and treatment are needed”) and discussion of evidence gaps in various places (Murray, 2020). Expressly stated was the hope to link evidence gaps with USPSTF criteria for study inclusion and coordinated efforts to describe and communicate evidence gaps so that they are easier to identify and address (Murray, 2020).

Arlene Bierman, director of AHRQ’s Center for Evidence and Practice Improvement, reinforced that the audience for the committee’s work was threefold: recommendation-making bodies, research funders, and researchers. Bierman also emphasized that the taxonomy and recommendations should account for the multiple dimensions of evidence gaps

(Bierman, 2020). Furthermore, discussions with AHRQ staff supporting the USPSTF and the USPSTF chair indicated that other goals for the committee are to provide immediate and long-term solutions that will help:

• Organizations that develop preventive services recommendations, such as the USPSTF, to more clearly communicate evidence gaps;
• Funding agencies, including NIH, to understand, assess the relative importance of, and use evidence gaps from preventive services recommendations in order to ultimately support research to fill the gaps;
• Members of the research community to focus their research on high-priority areas that have evidence gaps; and
• All stakeholders, including patients, to accelerate the translation of evidence gaps into funding opportunities and other initiatives that ultimately use innovative methods to close evidence gaps related to clinical preventive services (Bierman, 2020).

These discussions led the committee to understand that their taxonomy and recommendations should not be constrained by the history and current practices of the USPSTF.

COMMITTEE PROCESS

The committee held four open sessions to solicit input on its statement of task, the experiences of others in developing taxonomies, and the challenges for NIH and researchers to address I statements. The committee reviewed literature on taxonomies and, in an iterative fashion, developed and modified a taxonomy using 12 I statements as test candidates for the taxonomy. The committee selected a number of I statements to use as exemplars in developing its taxonomy. Throughout the report, the committee focuses on two specific I statements: Screening for Cognitive Impairment in Older Adults and Screening with ECG for Atrial Fibrillation. The committee also developed a workflow to show how to use its taxonomy to develop a research agenda.

The committee emphasized the USPSTF’s commitment to clinical prevention research as a means to advance health equity. The committee describes many opportunities that the USPSTF has to promote health equity in its work, starting with its topic identification and prioritization process. Where the committee saw an opportunity to advance health equity within this process, it has done so.

After identifying the long-term outcomes expected from the efforts led by AHRQ, ODP, and the USPSTF, the committee worked backward to assess what role its report (including the taxonomy) would play in AHRQ’s and ODP’s goals to improve clinical prevention research by addressing evidence gaps. The committee believes that the taxonomy and report’s recommendations will play an important but singular part in this undertaking. Knowing that the long-term outcome is to identify and close evidence gaps in clinical prevention research (particularly those gaps informed by letter grade recommendations and I statements issued by the USPSTF) more quickly, the committee outlines the process it believes will ultimately lead AHRQ, ODP, and the USPSTF to this outcome in Figure 5-1 (see Chapter 5). The committee identifies the activities, outputs, and outcomes that are necessary to achieve this impact, including the use of the evidence gaps taxonomy and other recommendations made by the committee in this report. Because the vision incorporates activities and outputs defined in the recommendations in this report, the figure and full description can be found in Chapter 5.

Although the figure is neither strictly a logic model nor theory of change, it incorporates elements of both. The committee’s vision includes the overall linearity of a logic model, articulating activities, outputs, and outcomes, and acknowledging that many elements within those categories already exist or have already been implemented by AHRQ, ODP, or the USPSTF. The vision also includes the assumptions and indicators associated with theories of change “through which the outcomes and activities work to achieve the desired impact” (Breuer et al., 2015; De Silva et al., 2014, p. 3).

ORGANIZATION OF THE REPORT

Chapter 2 describes the history and methods of the USPSTF, including how it and other CPG developers describe insufficient evidence. Chapter 3 describes the research enterprise involved in producing evidence for the USPSTF. Chapter 4 includes the taxonomy developed by the committee and describes how it can be used as part of a process to develop an actionable research agenda for USPSTF evidence gaps. Chapter 5 contains the committee’s recommendations, which are focused on three areas: using the taxonomy, fostering clinical prevention research, and advancing the work of the USPSTF. The chapter also describes the committee’s vision for improving clinical prevention research. Appendix A contains a comprehensive list of current I statements. Appendix B contains a description of research methods. Appendix C contains agendas from the committee’s public meetings. Appendix D contains the committee members’ and staff biographies. Appendix E contains summaries of the USPSTF’s annual reports to Congress. Appendix F reviews the research needs identified by the USPSTF in select I Statements.

REFERENCES

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