Putting Evidence Into Practice: An Update on the US Preventive Services Task Force Methods for Developing Recommendations for Preventive Services.

PURPOSE: The US Preventive Services Task Force (USPSTF) is an independent body that makes evidence-based recommendations regarding preventive services to improve health for people nationwide. Here, we summarize current USPSTF methods, describe how methods are evolving to address preventive health equity, and define evidence gaps for future research. METHODS: We summarize current USPSTF methods as well as ongoing methods development. RESULTS: The USPSTF prioritizes topics on the basis of disease burden, extent of new evidence, and whether the service can be provided in primary care and going forward will increasingly consider health equity. Analytic frameworks specify the key questions and linkages connecting the preventive service to health outcomes. Contextual questions provide information on natural history, current practice, health outcomes in high-risk groups, and health equity. The USPSTF assigns a level of certainty to the estimate of net benefit of a preventive service (high, moderate, or low). The magnitude of net benefit is also judged (substantial, moderate, small, or zero/negative). The USPSTF uses these assessments to assign a letter grade from A (recommend) to D (recommend against). I statements are issued when evidence is insufficient. CONCLUSIONS: The USPSTF will continue to evolve its methods for simulation modeling and to use evidence to address conditions for which there are limited data for population groups who bear a disproportionate burden of disease. Additional pilot work is underway to better understand the relations of the social constructs of race, ethnicity, and gender with health outcomes to inform the development of a USPSTF health equity framework.

USPSTF Approach to Addressing Sex and Gender When Making Recommendations for Clinical Preventive Services.

Clinical preventive service recommendations from the US Preventive Services Task Force (USPSTF) are based on transparent, systematic, and rigorous methods that consider the certainty of the evidence and magnitude of net benefit. These guidelines aim to address the needs of diverse populations. Biological sex and gender identity are sources of diversity that are not often considered in studies of clinical preventive services that inform the recommendations, resulting in challenges when evaluating the evidence and communicating recommendations for persons in specific gender identification categories (man/woman/gender nonbinary/gender nonconforming/transgender). To advance its methods, the USPSTF reviewed its past recommendations that included the use of sex and gender terms, reviewed the approaches of other guideline-making bodies, and pilot tested strategies to address sex and gender diversity. Based on the findings, the USPSTF intends to use an inclusive approach to identify issues related to sex and gender at the start of the guideline development process; assess the applicability, variability, and quality of evidence as a function of sex and gender; ensure clarity in the use of language regarding sex and gender; and identify evidence gaps related to sex and gender. Evidence reviews will identify the limitations of applying findings to diverse groups from underlying studies that used unclear terminology regarding sex and gender. The USPSTF will use gender-neutral language when appropriate to communicate that recommendations are inclusive of people of any gender and will clearly state when recommendations apply to individuals with specific anatomy associated with biological sex (male/female) or to specific categories of gender identity. The USPSTF recognizes limited evidence to inform the preventive care of populations based on gender identity.

Update on the Methods of the U.S. Preventive Services Task Force: Methods for Understanding Certainty and Net Benefit When Making Recommendations.

Since the 1980s, the U.S. Preventive Services Task Force (USPSTF) has developed and used rigorous methods to make evidence-based recommendations about preventive services to promote health and well-being for all Americans. Recommendations are based on the evidence of magnitude of net benefit (benefits minus harms). Expert opinion is not substituted when evidence is lacking. Evidence gaps are common. Few preventive services are supported by high-quality studies that directly and comprehensively determine the overall magnitude of benefits and harms in the same study. When assessing the body of evidence, studies may not have been conducted in primary care settings, studies may not have sufficiently included populations of interest, and long-term outcomes may not have been directly assessed. When direct evidence is not available, the USPSTF uses the methodologies of applicability to determine whether evidence can be generalized to an asymptomatic primary care population; coherence to link bodies of evidence and create an indirect evidence pathway; extrapolation to make inferences across the indirect evidence pathway, extend evidence to populations not specifically studied, consider service delivery intervals, and infer long-term outcomes; and conceptual bounding to set theoretical lower or upper limits for plausible benefits or harms. The USPSTF extends the evidence only so far as to maintain at least moderate certainty that its findings are preserved. This manuscript details with examples of how the USPSTF uses these methods to make recommendations that truly reflect the evidence.

Update on the Methods of the U.S. Preventive Services Task Force: Linking Intermediate Outcomes and Health Outcomes in Prevention.

The U.S. Preventive Services Task Force (USPSTF) is an independent body of experts who make evidence-based recommendations about clinical preventive services using a transparent and objective process. Developing recommendations on a clinical preventive service requires evidence of its effect on health outcomes. Health outcomes are symptoms, functional levels, and conditions that affect a patient's quantity or quality of life and are measured by assessments of physical or psychologic well-being. Intermediate outcomes are pathologic, physiologic, psychologic, social, or behavioral measures related to a preventive service. Given the frequent lack of evidence on health outcomes, the USPSTF uses evidence on intermediate outcomes when appropriate. The ultimate goal is to determine precisely a consistent relationship between the direction and magnitude of change in an intermediate outcome with a predictable resultant direction and magnitude of change in the health outcomes. The USPSTF reviewed its historical use of intermediate outcomes, reviewed methods of other evidence-based guideline-making bodies, consulted with other experts, and reviewed scientific literature. Most important were the established criteria for causation, tenets of evidence-based medicine, and consistency with its current standards. Studies that follow participants over time following early treatment, stratify patients according to treatment response, and adjust for important confounders can provide useful information about the association between intermediate and health outcomes. However, such studies remain susceptible to residual confounding. The USPSTF will exercise great caution when making a recommendation that depends on the evidence linking intermediate and health outcomes because of inherent evidence limitations.

Challenges in Developing U.S. Preventive Services Task Force Child Health Recommendations.

The U.S. Preventive Services Task Force (USPSTF) uses an objective evidence-based approach to develop recommendations. As part of this process, the USPSTF also identifies important research gaps in scientific evidence. In March 2016, the USPSTF convened an expert panel to discuss its portfolio of child and adolescent recommendations and identify unique methodologic issues when evaluating evidence regarding children and adolescents. The panel identified key domains of challenges, including measuring patient-centered health outcomes; identifying intermediate outcomes predictive of important health outcomes; evaluating the long time horizon needed to assess the balance of benefits and harms; understanding trajectories of growth and development that result in unique windows of time when expected benefits or harms of a preventive service can vary; and considering the perspectives of other individuals who might be affected by the delivery of a preventive service to a child or adolescent. Although the expert panel expressed an interest in being able to make more recommendations for or against preventive services for children and adolescents, it also reinforced the importance of ensuring recommendations were based on sound and sufficient evidence to ensure greatest benefit and minimize unnecessary harms. Accordingly, the need to highlight areas with insufficient evidence is as important as making recommendations. Having identified these key challenges, the USPSTF and other organizations issuing guidelines have an opportunity to advance their methods of evidence synthesis and identified evidence gaps represent important opportunities for researchers and policy makers.

Reconsidering the approach to prevention recommendations for older adults.

The U.S. Preventive Services Task Force (USPSTF) bases its recommendations on an evidence-based model of clinical prevention that focuses on specific diseases, well-defined preventive interventions, and evidence of improved health outcomes. Applying this model to prevention for very old patients has been problematic for several reasons: Many geriatric disorders have multiple risk factors, interventions, and expected outcomes; older adults are not often represented in clinical trials; and important outcomes may not be measured and reported in ways that are conducive to evidence synthesis and interpretation. In 2005, the USPSTF convened a geriatrics workgroup to refine USPSTF methodology and processes to better address the preventive needs of older adults. The USPSTF has begun to apply these new approaches to the review and recommendation on interventions to prevent falls in older adults.