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

The effect of cardiorespiratory fitness and habitual physical activity on cardiovascular responses to 2 h of uninterrupted sitting

Prolonged uninterrupted sitting of >3 h has been shown to acutely cause central and peripheral cardiovascular dysfunction. However, individuals rarely sit uninterrupted for >2 h, and the cardiovascular response to this time is currently unknown. In addition, while increased cardiorespiratory fitness (CRF) and habitual physical activity (HPA) are independently associated with improvements in central and peripheral cardiovascular function, it remains unclear whether they influence the response to uninterrupted sitting. This study sought to 1) determine whether 2 h of uninterrupted sitting acutely impairs carotid-femoral pulse wave velocity (cfPWV), femoral ankle PWV (faPWV), and central and peripheral blood pressure and 2) investigate the associations between CRF and HPA versus PWV changes during uninterrupted sitting. Following 2 h of uninterrupted sitting, faPWV significantly increased [mean difference (MD) = 0.26 m·s-1, standard error (SE) = 0.10, P = 0.013] as did diastolic blood pressure (MD = 2.83 mmHg, SE = 1.08, P = 0.014), however, cfPWV did not significantly change. Although our study shows 2 h of uninterrupted sitting significantly impairs faPWV, neither CRF (r = 0.105, P = 0.595) nor HPA (r = -0.228, P = 0.253) was associated with the increases.NEW & NOTEWORTHY We demonstrate that neither cardiorespiratory fitness nor habitual physical activity influence central and peripheral cardiovascular responses to a 2-h bout of uninterrupted sitting in healthy young adults.

The 24-h activity cycle and cardiovascular outcomes: establishing biological plausibility using arterial stiffness as an intermediate outcome

This review proposes a biologically plausible working model for the relationship between the 24-h activity cycle (24-HAC) and cardiovascular disease. The 24-HAC encompasses moderate-to-vigorous physical activity (MVPA), light physical activity, sedentary behavior (SB), and sleep. MVPA confers the greatest relative cardioprotective effect, when considering MVPA represents just 2% of the day if physical activity guidelines (30 min/day) are met. While we have well-established guidelines for MVPA, those for the remaining activity behaviors are vague. The vague guidelines are attributable to our limited mechanistic understanding of the independent and additive effects of these behaviors on the cardiovascular system. Our proposed biological model places arterial stiffness, a measure of vascular aging, as the key intermediate outcome. Starting with prolonged exposure to SB or static standing, we propose that the reported transient increases in arterial stiffness are driven by a cascade of negative hemodynamic effects following venous pooling. The subsequent autonomic, metabolic, and hormonal changes further impair vascular function. Vascular dysfunction can be offset by using mechanistic-informed interruption strategies and by engaging in protective behaviors throughout the day. Physical activity, especially MVPA, can confer protection by chronically improving endothelial function and associated protective mechanisms. Conversely, poor sleep, especially in duration and quality, negatively affects hormonal, metabolic, autonomic, and hemodynamic variables that can confound the physiological responses to next-day activity behaviors. Our hope is that the proposed biologically plausible working model will assist in furthering our understanding of the effects of these complex, interrelated activity behaviors on the cardiovascular system.

Reimagining the Value of Brachial-Ankle Pulse Wave Velocity as a Biomarker of Cardiovascular Disease Risk-A Call to Action on Behalf of VascAgeNet

This review critiques the literature supporting clinical assessment and management of cardiovascular disease and cardiovascular disease risk stratification with brachial-ankle pulse wave velocity (baPWV). First, we outline what baPWV actually measures-arterial stiffness of both large central elastic arteries and medium-sized muscular peripheral arteries of the lower limb. Second, we argue that baPWV is not a surrogate for carotid-femoral pulse wave velocity. While both measures are dependent on the properties of the aorta, baPWV is also strongly dependent on the muscular arteries of the lower extremities. Increased lower-extremity arterial stiffness amplifies and hastens wave reflections at the level of the aorta, widens pulse pressure, increases afterload, and reduces coronary perfusion. Third, we used an established evaluation framework to identify the value of baPWV as an independent vascular biomarker. There is sufficient evidence to support (1) proof of concept; (2) prospective validation; (3) incremental value; and (4) clinical utility. However, there is limited or no evidence to support (5) clinical outcomes; (6) cost-effectiveness; (8) methodological consensus; or (9) reference values. Fourth, we address future research requirements. The majority of the evaluation criteria, (1) proof of concept, (2) prospective validation, (3) incremental value, (4) clinical utility and (9) reference values, can be supported using existing cohort datasets, whereas the (5) clinical outcomes and (6) cost-effectiveness criteria require prospective investigation. The (8) methodological consensus criteria will require an expert consensus statement. Finally, we finish this review by providing an example of a future clinical practice model.

From guidelines to decision aids and adherence supports: Insights from the process of evidence translation

OBJECTIVE

To explore the evidence-translator's experience of the expert-recommended process of translating guidelines into tools for decision making, action, and adherence with the goal of improvement.

METHODS

A single reviewer dual reviewed the content, quality, certainty, and applicability of primary atherosclerotic cardiovascular prevention guidelines from the U.S. Preventive Services Task Force at the time of this work and used targeted searches of Medline to define the ideal structure and outcomes of tools; fill in gaps in guidelines; identify end-user needs; and choose and optimize existing tools in preparation for testing.

RESULTS

Guidelines addressed screening, treatments, and/or supports, but never the combination of all three. None provided all of the information needed for evidence translation. Searches in Medline filled in some evidence gaps and provided key insights into end-user needs and effective tools. However, evidence translators are left with complicated decisions about how to use and align evidence.

CONCLUSION

Guidelines provide some, but not all, of the evidence needed for evidence translation, requiring additional intensive work. Evidence gaps result in complicated decisions about how to use and align evidence and balance feasibility and rigor.

PRACTICE IMPLICATIONS

Guidelines, standards groups, and researchers should work to better support the process of evidence translation.

Influence of pilot and small trials in meta-analyses of behavioral interventions: a meta-epidemiological study

BACKGROUND

Pilot/feasibility or studies with small sample sizes may be associated with inflated effects. This study explores the vibration of effect sizes (VoE) in meta-analyses when considering different inclusion criteria based upon sample size or pilot/feasibility status.

METHODS

Searches were to identify systematic reviews that conducted meta-analyses of behavioral interventions on topics related to the prevention/treatment of childhood obesity from January 2016 to October 2019. The computed summary effect sizes (ES) were extracted from each meta-analysis. Individual studies included in the meta-analyses were classified into one of the following four categories: self-identified pilot/feasibility studies or based upon sample size but not a pilot/feasibility study (N ≤ 100, N > 100, and N > 370 the upper 75th of sample size). The VoE was defined as the absolute difference (ABS) between the re-estimations of summary ES restricted to study classifications compared to the originally reported summary ES. Concordance (kappa) of statistical significance of summary ES between the four categories of studies was assessed. Fixed and random effects models and meta-regressions were estimated. Three case studies are presented to illustrate the impact of including pilot/feasibility and N ≤ 100 studies on the estimated summary ES.

RESULTS

A total of 1602 effect sizes, representing 145 reported summary ES, were extracted from 48 meta-analyses containing 603 unique studies (avg. 22 studies per meta-analysis, range 2-108) and included 227,217 participants. Pilot/feasibility and N ≤ 100 studies comprised 22% (0-58%) and 21% (0-83%) of studies included in the meta-analyses. Meta-regression indicated the ABS between the re-estimated and original summary ES where summary ES ranged from 0.20 to 0.46 depending on the proportion of studies comprising the original ES were either mostly small (e.g., N ≤ 100) or mostly large (N > 370). Concordance was low when removing both pilot/feasibility and N ≤ 100 studies (kappa = 0.53) and restricting analyses only to the largest studies (N > 370, kappa = 0.35), with 20% and 26% of the originally reported statistically significant ES rendered non-significant. Reanalysis of the three case study meta-analyses resulted in the re-estimated ES rendered either non-significant or half of the originally reported ES.

CONCLUSIONS

When meta-analyses of behavioral interventions include a substantial proportion of both pilot/feasibility and N ≤ 100 studies, summary ES can be affected markedly and should be interpreted with caution.

Protocol for a study on Sitting with Interruption and Whole-Body Cardiovascular Health (SWITCH) in middle-aged adults

BACKGROUND

Sedentary behavior (SB) is a biologically distinct yet understudied cardiovascular disease risk (CVD) factor. However, specific public health policy regarding the optimal strategy for SB interruption is unavailable. This paper outlines the protocol for part I of the Sitting with Interruption and Whole-Body Cardiovascular Health (SWITCH) study, including the rationale, objectives, methodology, and next steps. We additionally detail practical considerations that went into the development of the NIH R01 grant supporting this research.

METHODS

Healthy men and women (n = 56, aged 36-55) who are inactive (<90 min/wk. of moderate-to-vigorous intensity physical activities for past 3 months) and sedentary (sitting for >8 h/day), will be recruited for this randomized crossover trial. Specifically, participants will complete the following 4-h conditions: (i) SB with once/h 5 min walk break; (ii) SB with once/h 15 min stand break; (iii) SB with twice/h breaks (alternating 5 min walk and 15 min stand); and (iv) SB with no breaks (i.e., control). Focus group discussions will refine our socioecological SB reduction model.

RESULTS

The primary outcome will be change in aortic arterial stiffness (i.e., pulse wave velocity; PWV, m/s) for each substitution strategy relative to the control (SB with no breaks) condition.

CONCLUSIONS

The outcomes from this study will facilitate the design of a subsequent randomized controlled trial to test a mechanism-informed, feasible SB-reduction intervention and support the development of SB policy.

[Summary PAPPS Childhood and Adolescence 2022]

Two important topics about children and adolescents in our primary care activity are presented in this update document: tobacco smoking prevention in adolescence and prophylaxis with vitamin K to prevent the hemorrhagic disease of the newborn.

Addressing eating disorders in primary care: Understanding screening recommendations and opportunities to improve care

OBJECTIVE

For the first time in its history, the United States Preventive Services Task Force (USPSTF) published a recommendation on screening for eating disorders among adolescents and adults in primary care. The current manuscript provides an overview of the USPSTF recommendation, screening principles, and suggestions for clinical and research efforts.

METHOD

The USPSTF based their recommendations on a rigorous systematic review of the evidence on routine screening for eating disorders. Eligible studies included studies of screening test accuracy and controlled trials of screening or interventions for eating disorders in screen-detected or previously untreated eating disorders. The current manuscript briefly summarizes the results of this evidence review which are published in full elsewhere and focuses on providing interpretation of the recommendations by clarifying the scope and methodology of the USPSTF.

RESULTS

Fifty-seven studies were included in the evidence review. Seventeen studies evaluated screening test accuracy and 40 trials evaluated interventions among populations with previously untreated eating disorders. No studies directly assessed the benefits and harms of screening. The evidence review highlights important gaps in our knowledge regarding eating disorders in primary care. The authors provide recommendations for future studies in light of these evidence gaps and propose specific clinical strategies to improve care for those with eating disorders who present to primary care.

DISCUSSION

Primary care can play an important role in the early detection of eating disorders, but data are needed to more fully understand the potential benefits and harms of routine screening in this setting.

PUBLIC SIGNIFICANCE

There are gaps in the evidence regarding the benefits and harms of eating disorder screening in primary care. Future studies are needed to improve certainty about the net benefit of screening. Of particular importance are studies that compare routine screening to usual care (no screening). Current providers may benefit from tailored eating disorders education and training, practical tools, and integration of mental health services in primary care.

Screening and Interventions for Social Risk Factors: Technical Brief to Support the US Preventive Services Task Force

IMPORTANCE

Evidence-based guidance is limited on how clinicians should screen for social risk factors and which interventions related to these risk factors improve health outcomes.

OBJECTIVE

To describe research on screening and interventions for social risk factors to inform US Preventive Services Task Force considerations of the implications for its portfolio of recommendations.

DATA SOURCES

Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Ovid MEDLINE, Sociological Abstracts, and Social Services Abstracts (through 2018); Social Interventions Research and Evaluation Network evidence library (January 2019 through May 2021); surveillance through May 21, 2021; interviews with 17 key informants.

STUDY SELECTION

Individual-level and health care system-level interventions with a link to the health care system that addressed at least 1 of 7 social risk domains: housing instability, food insecurity, transportation difficulties, utility needs, interpersonal safety, education, and financial strain.

DATA EXTRACTION AND SYNTHESIS

One investigator abstracted data from studies and a second investigator evaluated data abstractions for completeness and accuracy; key informant interviews were recorded, transcribed, summarized, and integrated with evidence from the literature; narrative synthesis with supporting tables and figures.

MAIN OUTCOMES AND MEASURES

Validity of multidomain social risk screening tools; all outcomes reported for social risk-related interventions; challenges or unintended consequences of screening and interventions.

RESULTS

Many multidomain social risk screening tools have been developed, but they vary widely in their assessment of social risk and few have been validated. This technical brief identified 106 social risk intervention studies (N = 5 978 596). Of the interventions studied, 73 (69%; n = 127 598) addressed multiple social risk domains. The most frequently addressed domains were food insecurity (67/106 studies [63%], n = 141 797), financial strain (52/106 studies [49%], n = 111 962), and housing instability (63/106 studies [59%], n = 5 881 222). Food insecurity, housing instability, and transportation difficulties were identified by key informants as the most important social risk factors to identify in health care. Thirty-eight studies (36%, n = 5 850 669) used an observational design with no comparator, and 19 studies (18%, n = 15 205) were randomized clinical trials. Health care utilization measures were the most commonly reported outcomes in the 68 studies with a comparator (38 studies [56%], n = 111 102). The literature and key informants described many perceived or potential challenges to implementation of social risk screening and interventions in health care.

CONCLUSIONS AND RELEVANCE

Many interventions to address food insecurity, financial strain, and housing instability have been studied, but more randomized clinical trials that report health outcomes from social risk screening and intervention are needed to guide widespread implementation in health care.

Screening for Hepatitis B Virus Infection in Nonpregnant Adolescents and Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

Importance

A 2014 review for the US Preventive Services Task Force (USPSTF) found antiviral therapy for hepatitis B virus (HBV) infection associated with improved intermediate outcomes, although evidence on clinical outcomes was limited.

Objective

To update the 2014 HBV screening review in nonpregnant adolescents and adults to inform the USPSTF.

Data Sources

Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and Ovid MEDLINE (2014 to August 2019); with surveillance through July 24, 2020.

Study Selection

Randomized clinical trials (RCTs) on screening and antiviral therapy; cohort studies on screening, antiviral therapy clinical outcomes, and the association between achieving intermediate outcomes after antiviral therapy and clinical outcomes.

Data Extraction and Synthesis

One investigator abstracted data; a second investigator checked accuracy. Two investigators independently assessed study quality. Random-effects profile likelihood meta-analysis was performed.

Results

Thirty trials and 20 cohort studies, with a total of 94 168 participants, were included. No study directly evaluated the effects of screening for HBV infection vs no screening on clinical outcomes such as mortality, hepatocellular carcinoma, or cirrhosis. Screening strategies that focused on risk factors such as ever having immigrated from high-prevalence countries and demographic and behavioral risk factors would identify nearly all HBV infection cases. In 1 study (n = 21 008), only screening immigrants from high-prevalence countries would miss approximately two-thirds of infected persons. Based on 18 trials (n = 2972), antiviral therapy compared with placebo or no treatment was associated with greater likelihood of achieving intermediate outcomes, such as virologic suppression and hepatitis B e-antigen (HBeAg) or hepatitis B surface antigen loss or seroconversion; the numbers needed to treat ranged from 2.6 for virologic suppression to 17 for HBeAg seroconversion. Based on 12 trials (n = 4127), first-line antiviral therapies were at least as likely as nonpreferred therapies to achieve intermediate outcomes. Based on 16 trials (n = 4809), antiviral therapy might be associated with improved clinical outcomes, but data were sparse and imprecise. Nine cohort studies (n = 3893) indicated an association between achieving an intermediate outcome following antiviral therapy and improved clinical outcomes but were heterogeneous (hazard ratios ranged from 0.07 to 0.87). Antiviral therapy was associated with higher risk of withdrawal due to adverse events vs placebo or no antiviral therapy.

Conclusions and Relevance

There was no direct evidence for the clinical benefits and harms of HBV screening vs no screening. Antiviral therapy for HBV infection was associated with improved intermediate outcomes and may improve clinical outcomes.

Effect of Incorporating Genetic Testing Results into Nutrition Counseling and Care on Health Outcomes: An Evidence Analysis Center Systematic Review-Part II

In recent years, literature examining implementation of nutritional genomics into clinical practice has increased, including publication of several randomized controlled trials (RCTs). This systematic review addressed the following question: In children and adults, what is the effect of incorporating results of genetic testing into nutrition counseling and care compared with an alternative intervention or control group, on nutrition-related health outcomes? A literature search of MEDLINE, Embase, PsycINFO, CINAHL, and other databases was conducted for peer-reviewed RCTs published from January 2008 until December 2018. An international workgroup consisting of registered dietitian nutritionists, systematic review methodologists, and evidence analysts screened and reviewed articles, summarized data, conducted meta-analyses, and graded conclusion statements. The second in a two-part series, this article specifically summarizes evidence from RCTs that examined health outcomes (ie, quality of life, disease incidence and prevention of disease progression, or mortality), intermediate health outcomes (ie, anthropometric measures, body composition, or relevant laboratory measures routinely collected in practice), and adverse events as reported by study authors. Analysis of 11 articles from nine RCTs resulted in 16 graded conclusion statements. Among participants with nonalcoholic fatty liver disease, a diet tailored to genotype resulted in a greater reduction of percent body fat compared with a customary diet for nonalcoholic fatty liver disease. However, meta-analyses for the outcomes of total cholesterol, low-density lipoprotein cholesterol, body mass index, and weight yielded null results. Heterogeneity between studies and low certainty of evidence precluded development of strong conclusions about the incorporation of genetic information into nutrition practice. Although there are still relatively few well-designed RCTs to inform integration of genetic information into the Nutrition Care Process, the field of nutritional genomics is evolving rapidly, and gaps in the literature identified by this systematic review can inform future studies.

Social Determinants as a Preventive Service: U.S. Preventive Services Task Force Methods Considerations for Research

The body of research on social determinants of health is rapidly accumulating. The U.S. Preventive Services Task Force is conducting evaluations to consider the inclusion of screening and counseling for social risks as a clinical preventive service. Yet, for many social risks, evidence is still likely needed before the U.S. Preventive Services Task Force can recommend universal screening or counseling. This manuscript offers a brief review of the social determinants of health that may be germane to the U.S. Preventive Services Task Force, the methods the U.S. Preventive Services Task Force uses to evaluate relevant evidence, and current evidence gaps for social risks. Key methods for making clinical preventive service recommendations are applied for considering the integration of social and clinical care. These methods include determining the certainty of the evidence, assessing the net benefit, defining appropriate prevention frameworks, defining health outcomes versus intermediate outcomes, fully assessing the harms, and defining to what populations and care contexts the evidence applies. This road map for research is intended to spark ingenuity and purpose in the next generation of research studies, thereby ensuring that future recommendations to address and prevent social risks in primary care are informed by high-quality evidence. SUPPLEMENT INFORMATION: This article is part of a supplement entitled Identifying and Intervening on Social Needs in Clinical Settings: Evidence and Evidence Gaps, which is sponsored by the Agency for Healthcare Research and Quality of the U.S. Department of Health and Human Services, Kaiser Permanente, and the Robert Wood Johnson Foundation.

Exercise effects on quality of life, mood, and self-worth in overweight children: the SMART randomized controlled trial

Overweight children are at risk for poor quality of life (QOL), depression, self-worth, and behavior problems. Exercise trials with children have shown improved mood and self-worth. Few studies utilized an attention control condition, QOL outcomes, or a follow-up evaluation after the intervention ends. The purpose is to test effects of an exercise program versus sedentary program on psychological factors in overweight children. One hundred seventy-five overweight children (87% black, 61% female, age 9.7 ± 0.9 years, 73% obese) were randomized to an 8 month aerobic exercise or sedentary after-school program. Depressive symptoms, anger expression, self-worth, and QOL were measured at baseline and post-test. Depressive symptoms and QOL were also measured at follow-up. Intent-to-treat mixed models evaluated intervention effects, including sex differences. At post-test, QOL, depression, and self-worth improved; no group by time or sex by group by time interaction was detected for QOL or self-worth. Boys' depressive symptoms improved more and anger control decreased in the sedentary intervention relative to the exercise intervention at post-test. At follow-up, depressive symptoms in boys in the sedentary group decreased more than other groups. Exercise provided benefits to QOL, depressive symptoms, and self-worth comparable to a sedentary program. Sedentary programs with games and artistic activities, interaction with adults and peers, and behavioral structure may be more beneficial to boys' mood than exercise. Some benefits of exercise in prior studies are probably attributable to program elements such as attention from adults. Trial Registration: Clinicaltrials.gov, NCT02227095.

Environmental Health Sciences in a Translational Research Framework: More than Benches and Bedsides

BACKGROUND

Environmental health scientists may find it challenging to fit the structure of the questions addressed in their discipline into the prevailing paradigm for translational research.

OBJECTIVE

We aim to frame the translational science paradigm to address the stages of scientific discovery, knowledge acquisition, policy development, and evaluation in a manner relevant to the environmental health sciences. Our intention is to characterize differences between environmental health sciences and clinical medicine, and to orient this effort towards public health goals.

DISCUSSION

Translational research is usually understood to have evolved from the bench-to-bedside framework by which basic science transitions to clinical treatment. Although many health-related fields have incorporated the terminology and context of translational science, environmental health research has not always found a clear fit into this paradigm. We describe a translational research framework applicable to environmental health sciences that retains the basic structure that underlies the original bench-to-bedside paradigm. We propose that scientific discovery (T1) in environmental health research frequently occurs through epidemiological or clinical observations. This discovery often involves understanding the potential for human health effects of exposure to a given environmental chemical or chemicals. The practical applications of this discovery evolve through an understanding of exposure-response relationships (T2) and identification of potential interventions to reduce exposure and improve health (T3). These stages of translation require an interdisciplinary partnership between exposure sciences, exposure biology, toxicology, epidemiology, biostatistics, risk assessment, and clinical sciences. Implementation science then plays a crucial role in the development of environmental and public health practice and policy interventions (T4). Outcome evaluation (T5) often takes the form of accountability research, as environmental health scientists work to quantify the costs and benefits of these interventions.

CONCLUSION

We propose an easily visualized framework for translation of environmental health science knowledge-from discovery to public health practice-that reflects the crucial interactions between multiple disciplines in our field. https://doi.org/10.1289/EHP4067.

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.

Evaluating Evidence on Intermediate Outcomes: Considerations for Groups Making Healthcare Recommendations

INTRODUCTION

Groups making recommendations need evidence about whether preventive services improve health outcomes (HOs). When such evidence is not available, groups may choose to evaluate evidence about effects on intermediate outcomes (IOs) and the link between IOs and HOs. This paper aims to describe considerations for assessing the evidence linking changes in IOs to changes in HOs.

METHODS

Working definitions of IOs, HOs, and other outcomes were developed. All current U.S. Preventive Services Task Force (USPSTF) recommendations through April 2016 were examined to identify how evidence of the IO-HO link was gathered and the criteria that appeared to be used to determine the adequacy of the evidence. Methods of other expert and recommendation-making groups were also examined.

RESULTS

Forty-four USPSTF recommendations involved a relevant IO-HO link. The approaches used most commonly to gather evidence about the link were selected review (19 of 44, 43%) and systematic review (12 of 44, 27%). Some key considerations when assessing the adequacy of evidence about the IO-HO link include adjustment for confounding, proximity of the IO to the HO in the causal pathway, and independence of IO-HO relationship from specific treatments.

CONCLUSIONS

Considerations were identified for recommendation-making groups to use when gathering and assessing the adequacy of evidence about the IO-HO link. Using a standard set of written principles could improve the transparency of assessments of the IO-HO link, especially if used together with judgment in a reasoned conjecture and refutation process. Ideally, the process would result in an estimate of the magnitude of change in HOs that is expected for specified changes in IOs.

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.

U.S. Preventive Services Task Force Priorities for Prevention Research

The U.S. Preventive Services Task Force (USPSTF) makes recommendations about clinical preventive services. The USPSTF examines chains of direct and indirect evidence to demonstrate the effectiveness of a clinical preventive service. Missing links across the chains of evidence reflect gaps in the research. Evidence gaps can occur for preventive services that receive a letter grade recommendation and those that receive an I statement (insufficient evidence). This article describes the types of evidence gaps that the USPSTF encounters across its various recommendations and how the USPSTF identifies and communicates these gaps to researchers and policymakers, who can help generate the needed evidence. Common types of evidence gaps include limited evidence in primary care settings and populations, a lack of appropriate health outcomes, limited evidence linking behavior change to health outcomes, and a lack of evidence for effective preventive services in diverse populations. The USPSTF annual report to Congress focuses on the evidence gaps of new recommendations from the past year and is sent to leading research funding agencies. The Office of Disease Prevention at NIH uses this report to help direct future funding opportunities that may address these evidence gaps. The USPSTF plays a critical role in highlighting the information needed to advance the science to optimize the use of clinical preventive services in primary care.