Clinical Hypertension Guidelines and Social Determinants of Health: A Systematic Scoping Review

Social and economic factors impact hypertension risk and control. We examined the integration of social determinants of health (SDH) guidance into adult US hypertension guidelines to explore how existing hypertension guidelines reference social care activities. Objective To explore how existing hypertension management guidelines reference social care activities. Systematic scoping review of clinical guidelines (guidelines, protocols, and professional organization statements) for adult hypertension management. We employed a PubMed search strategy to identify all hypertension guidelines and protocols published in the US between 1977 and 2019. We reviewed all titles to identify the most updated versions focused on non-pregnant adults with essential hypertension. We extracted instances where included guidelines referred to social determinants of health or social care. The primary outcome was how guidelines covered topics related to social care, dened using a framework adapted from the National Academies of Sciences, Engineering and Medicine (NASEM).


Abstract
Background Social and economic factors impact hypertension risk and control. We examined the integration of social determinants of health (SDH) guidance into adult US hypertension guidelines to explore how existing hypertension guidelines reference social care activities.

Objective
To explore how existing hypertension management guidelines reference social care activities.

Methods
Systematic scoping review of clinical guidelines (guidelines, protocols, and professional organization statements) for adult hypertension management. We employed a PubMed search strategy to identify all hypertension guidelines and protocols published in the US between 1977 and 2019. We reviewed all titles to identify the most updated versions focused on non-pregnant adults with essential hypertension. We extracted instances where included guidelines referred to social determinants of health or social care. The primary outcome was how guidelines covered topics related to social care, de ned using a framework adapted from the National Academies of Sciences, Engineering and Medicine (NASEM).

Results
Search terms yielded 126 guidelines. Thirty-six guidelines met inclusion criteria. Of those 72% (26/36) recommended social care activities as part of hypertension management; 58% recommended clinicians change clinical care practice based on social risk information. These recommendations often lacked speci c guidance around how to address SDH. When guidelines referred to speci c social factors, patient nancial security was the most common social determinant highlighted (n = 101). Ten guidelines (28%) did not reference social care activities.

Conclusion
Information about social determinants of health is included in many adult hypertension management guidelines, but few guidelines provide clear guidance for clinicians on how to identify and address actionable social risk factors in the context of care delivery.

Background
Page 3/20 One third of US adults have hypertension, a major risk factor for mortality from heart disease and stroke (1). Despite the life threatening consequences of uncontrolled hypertension and numerous treatment guidelines for elevated blood pressure, hypertension control is achieved in only half of those diagnosed (1). Hypertension control in the US has improved over the last two decades (from 31.5% for 1999-2000 to 53.3% for 2009-2010), but signi cant disparities persist (2,3). Lower income and absence of health insurance increase the risk of uncontrolled hypertension (4,5). Disparities in blood pressure control likely contribute to higher cardiovascular morbidity and mortality among vulnerable and low socioeconomic groups (2,(6)(7)(8). Given the extent and consequences of uncontrolled disease, hypertension control is a central focus of public health, primary care, and several medical sub-specialties.
The rapidly evolving science around social determinants of health (SDH) is relevant to efforts to improve hypertension management. These SDH range from upstream political and social in uences to more downstream, non-medical factors in patients' physical and social environments that in uence the ability to prevent hypertension and adhere to treatment recommendations. As examples, nancial resources affect a patient's ability to purchase medication and healthy food (5); housing stability and quality impact medication storage and access to primary and preventative care (9); restroom access may in uence diuretic adherence(10); transportation availability improves clinic attendance (11)(12)(13); and both literacy and language can affect patients' understanding medication use (14). As a result, over the last decade the health care sector's interest in and activities around patients' social conditions have expanded (15). We conducted a scoping review of published guidelines on adult hypertension to explore if and how existing guidelines direct clinicians to ask about and to address patients' social conditions as part of hypertension management.

Data Sources and searches
We conducted a systematic scoping review of clinical guidelines and standards for essential hypertension management in adults. A systematic scoping review is the preferred review method "when a body of literature has not yet been comprehensively reviewed, or exhibits a large, complex, or heterogenous nature not amenable to a more precise systematic review," (16) which is the case in this evolving area of SDH research. Our method was similar to prior scoping reviews (17,18), and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) recommendations.
We de ned guidelines as published recommendations for the management of elevated blood pressure, typically in collaboration with a professional organization (for example, National Heart Lung and Blood Institute (NHLBI), American Heart Association (AHA), American College of Cardiology (ACC), American Society of Hypertension (ASH)). Our team worked with an academic medical librarian to develop our search protocol and solicit feedback from our research team. Protocol is available on request from the corresponding author. Using PubMed, we searched for publication type using: hypertension guidelines, clinical guidelines, and clinical recommendations published in the US including all dates up to our search Race and socioeconomic status are often intertwined in the US. Since social care interventions in the NASEM report were not de ned by race, for the purposes of this review we did not extract guideline text related to race. The 2019 Healthy People 2020 report similarly excludes race as an SDH category (19).

Data synthesis and analysis
We summed types of recommendations by social care category. Additionally, within each social care category, we included the frequency of each type of SDH mentioned within guidelines (see Appendix 2).

Results
We screened 126 titles and reviewed 120 guidelines after excluding 6 duplicates. Thirty-six guidelines met our inclusion criteria (see Table 1 for PRISMA diagram). Of the 36 guidelines reviewed, 10 guidelines (28%) included awareness activities. Twenty-one guidelines (58%) made adjustment recommendations.
Six guidelines (17%) mentioned assistance strategies. Five (14%) guidelines mentioned alignment strategies, and eight guidelines (22%) included advocacy recommendations. One guideline acknowledged SDH without referencing any social care activities. Of all reviewed guidelines, 28% (n=10) neither acknowledged SDH nor referenced health activities related to SDH (See Table 2 for summary and Appendix 2 for breakdown of results). Guidelines published in 2019 were more likely to include multiple categories of social care activities than guidelines published in 1991 (the earliest guideline included).

Awareness
Ten guidelines (28%) recommended activities to identify or screen for social risks and assests of de ned patients and populations. This included screening for patients' ability to pay for medication, health literacy, food access, and transportation availability. As example, a 2004 guideline discussed screening for nancial security, health literacy, and insurance status (20); a 1993 guideline on mild hypertension, suggested screening for health literacy(21); the 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure encouraged clinicians to inquire about care affordability (5).
Only the 2019 Clinical Performance and Quality Measures report recommended the use of a standardized social risk screening tool(22).

Adjustment
Twenty-one guidelines (58%) recommended activities to adjust clinical care based on patients' social risks. The NASEM report underscores that these activities (to accommodate care to patients' social circumstances) differ from assistance interventions in that they do not intervene on the social risk itself, but instead change care planning based on the social risk. Of the total 63 speci c care adjustments mentioned across the 21 guidelines, over half (57% n=36/63) focused on adjustments to accommodate patients' nancial security. In these cases, authors acknowledged that cost is a barrier to medication adherence (and therefore hypertension control) and in various ways suggested changing care to reduce medication cost burdens(21,23). Speci c examples included prescribing generic alternatives(5,24-27), once daily dosages (5,25), combination pills (28), long-acting medication formulations (5,27), and increasing the number of pills dispensed in each prescription to minimize pharmacy visits and copayments (5). The 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure also recommended providing patients with scored tablets or pill cutters to reduce costs (5).
Guidelines also included other strategies to accommodate access barriers. For instance, guidelines described efforts to limit the number and frequency of medical vists (29); increase telehealth (22); utilize electronic health record to tailor health advice to patients based on their social risk (22); use remote blood pressure monitoring (26,30,31); or offer medication home delivery (22). Two highlighted opportunities to minimize laboratory tests (23,31). Three others suggested addressing patients' transportation barriers through reducing frequency of o ce visits to minimize co-payments (5,31,32). A 2013 guideline recommended that emergency medicine physicians initiate blood pressure medications in asymptomatic patients when patients were in social circumstances that might prevent them from establishing primary care (33).
In addition to adjustments to reduce patient cost, several guidelines recommended adjusting care for patients based on education, literacy level, and cultural background (5,23). Speci c examples included ensuring the presence of translators, improving providers' cultural competency, and increasing the availability of linguistically-appropriate educational materials (5,23,34).
A 2019 Clinical Performance and Quality Measures report highlighted that health systems can omit patients from the denominator of some hypertension quality metrics if patients have economic or access barriers to medication adherence(22).

Assistance
Six guidelines (17%) described assistance strategies for health care teams to improve patients' hypertension management by directly intervening on social risks themselves. These recommendations involved using clinic or community-based social service providers, e.g. community health workers, social workers, or case managers, to facilitate connections with community or government social services (22,29), including housing programs, food banks or other nutrition programs (23,35), insurance or medication access programs (35), or utility assistance programs(5).

Alignment
The 2019 NASEM framework also de ned health care sector activities outside of clinical care related to strengthening community SDH resources and supports. Five (14%) guidelines raised topics related to alignment strategies. For example, a 2005 publication on cardiovascular disease and minority health recommended several community education strategies, such as dissemination of physical activity and nutrition information to marginalized communities (34). JNC7 and the 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure elevated community organizations as liaisons to bridge cultural and language barriers and establish community-based HTN screening and referral programs (5,35). A 2019 report highlighted ways to strengthen community partnerships that provide healthy food and enroll individuals in federal nutrition assistance programs (22).

Advocacy
Eight guidelines (22%) described ways that health care organizations can promote policies or societal investments that increase the availability of social resources as part of a strategy for reducing hypertension prevalence and morbidity. Seven of these described ways health systems can work with insurers to improve incentives and/or lower costs of care. In the 2017 Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure, the authors wrote: "Greater attention is being paid to the in uence of health insurance coverage and bene t designs focused on reducing patient copayments for antihypertensive medications" (5). Beyond copayments and coverage, several guidelines referenced speci c activities that if reimburseable, could improve hypertension control, including obesity treatments (34) and home blood pressure monitors (HBPM) (36); one emphasized the importance of developing quality measures related to SDH to standardize blood pressure management (22).
Five guidelines surfaced the importance of healthy food access as a key area for societal interventions (5,34,35,37,38). These guidelines emphasized the need for policy changes to increase the availability of healthy foods and access to physical activity. A 2017 guideline called on food manufacturers to reduce "the amount of sodium in food processing, as well as in fast food and restaurant food preparation"(5). This echoes earlier guidelines' suggestions to reduce marketing of "highcalorie, low-nutrient-density products to young children or people of color" (34) and to lobby the food industry "to progressively reduce the salt added to foods by 50% over the next 10 years" (38).
Four guidelines called for increased research funding to improve evidence on the social and economic aspects of blood pressure control (5,22,23,34). This included advocating for researchers, clinicians, and research subjects from diverse backgrounds (34) and increased focus on care in low socioeconomic settings(5).

Acknowledgement
Of the 36 guidelines, 10 did not reference social determinants of health or related search terms. Of the remaining 26, one guideline described the relevance of SDH to hypertension management but did not refer to any NASEM action categories (awareness, assistance, adjustment, alignment, or advocacy) in the rest of the guideline sections. Seventeen guidelines included text acknowledging that SDH in uence hypertension management in sections that did not otherwise recommend a speci c social care activity. In these seventeen guidelines, authors referred to at least one NASEM action category in another section. Economic constraints (described in 36 of the 84 references to acknowledgement activities) were the most common social domain mentioned without explicit social care recommendations. In these instances, nancial status was generally linked with hypertension risk factors and care(5,21,22,26,29,34,35,39) or to more speci c hypertension treatment barriers, such as medication affordability (5,(22)(23)(24)26,29,35,40), lack of health insurance coverage (5,23,29,34,41), or otherwise limited access to care (25)(26)(27)29,34,35,39). Beyond nancial risk, multiple guidelines referred to language and education barriers to prevention and treatment (5,22,23,25,26,29,35), absence of safe space for physical activity (5,35), and lack of adequate healthy food (5,27,31,34,35,38).

Conclusion
Across the US there is growing recognition that patients' social conditions affect disease risk, severity, and treatment. In hypertension, there is strong and compelling evidence that SDH such as education, nancial stability, and access to healthcare impact blood pressure control and other cardiovascular disease (42). In this review of 36 adult hypertension management guidelines, 3/4 of guidelines acknowledged these associations between SDH and hypertension management and outcomes. Not surprisingly, references to SDH were more common in more recent publications. Nearly 1/3 of the guidelines, however, did not include recommendations for health care clinical teams or health care systems regarding actions to address SDH to improve hypertension prevention or treatment. When they were made, recommendations were inconsistent across different guidelines. Review ndings suggest that there are ongoing translational gaps between the impact of social care on hypertension management and how equipped clinicians and health systems are to use that information to improve patient and population health.
What else do these ndings tell us about hypertension-related social care? First, in cases where guidelines did make social care recommendations, there is an incongruence between screening and intervention recommendations. Of the 27 guidelines that recommended clinical care changes (whether adjustment or assistance) based on patients' social risk, only 10 recommended some form of social risk screening. Of those, only one suggested using a standardized social risk assessment tool (22). This may re ect the fact that more evidence is needed on social risk screening, including measure validity, implementation feasibility, and relevance for informing subsequent interventions (43). Prior research not limited to hypertension suggests patients nd social risk screening acceptable (44,45) and that clinicians are unlikely to accurately gauge patients' social risks without those assessments (46). Without robust social risk assessments, targeting patients with hypertension who could bene t from social care programs will be more di cult and any effective interventions will be underutilized.
Second, though there are instances where adjustment and assistance recommendations were described in hypertension guidelines, there is little consistency or evidence-based information in the guidelines about how clinicians can intervene on social risk to improve hypertension outcomes. For instance, only nine of the 36 guidelines suggested changes to medication regimens to address hypertension treatment barriers for low-income patients (5,21,23,25,26,28,29,31,39). There is considerable evidence on this topic that could be re ected in future guideline development. One recent review found that use of brand name antihypertensive medications resulted in higher costs for patients and lowered adherence (47). Other studies found that combination pills, which include two or more medications in a single pill, improved adherence, likely both because combination pills lower costs and reduce regimen complexity (48,49). Medication adherence decreases consistently with each additional antihypertensive medication prescribed (50). A multi-pronged approach to hypertension intended to decrease health disparities across Kaiser Permanente involved SDH-related adjustment strategies, including standardized treatment algorithms to encourage combination pills as rst line treatment (therefore reducing the number of pills, frequency of dosing, and costs) (51)(52)(53). Several studies have documented improved blood pressure medication adherence with reduced co-payments(54-56).
Only ve guidelines described SDH adjustment strategies related to care cost and coverage not speci c to medications (this included recommending home blood pressure monitors, longer medication re lls to reduce pharmacy trips, and increasing telehealth options). Similarly, future guidelines should review related evidence in this area. A review of international health systems found that having health insurance coverage, a regular physician, and minimal copayments improved hypertension management (57). In addition, a study offering free care to low-income individuals with hypertension improved diastolic blood pressure and reduced CVD risk (56,58). This evidence underscores that while low cost medications could improve hypertension control for all individuals, they are particularly important for vulnerable groups.
Other adjustment strategies that rarely appeared in the guidelines involve using multi-disciplinary care teams to provide care concordant with patients' language, literacy, and cultural norms or to bridge patients to community or government programs that provide social services. But here, too, there is a growing evidence base speci c to hypertension on which to draw in future guideline development. For example, health education programs for patients with poor literacy have improved systolic blood pressure (14,59). Community health worker-delivered counseling and education around cardiovascular risk prevention improved both systolic and diastolic blood pressure (60)(61)(62). Peer education and increased workforce diversity both maximized language concordance between patients and providers and reduced hypertension disparities between different patient groups in Kaiser's southern California region (53). And a 2017 primary care based study found that social screening and assistance-type navigation services modestly improved blood pressure and lipid levels (63). Overall, future guidelines might better incorporate emerging, multi-disciplinary research on interventions that can mitigate the impacts of socioeconomic risks on blood pressure control and adherence (49,50,66,51,52,(54)(55)(56)(63)(64)(65)including adjustments to medication, cost of care, and team-based care.
Finally, 22% of the treatment guidelines included advocacy recommendations as a strategy to improve hypertension care, but these recommendations were rarely accompanied by evidence about the effective roles for health care professionals in those advocacy activities. Since some health professionals are hesitant to embrace advocacy roles (67) and others lack skills and/or opportunities to participate in advocacy, operationalizing these recommendations is likely to require dedicated training and supports for health professionals (68).
Our study has several limitations. Given that the National Guideline Clearinghouse closed in 2018, it is di cult to ensure that we identi ed all relevant adult essential hypertension guidelines. We consulted with a medical librarian to design our search strategy, however, and there is no reason that omitted guidelines should systematically differ from those included in the review. Our review also was limited to published guidelines in the United States. Countries with different health care infrastructure and payment models may better address patients' social contexts as part of care delivery. We did not include race in our SDH-related search strategy. Yet we recognize that race, racism, and discrimination are inextricably tied to SDH in the US. Future reviews should explore how hypertension guidelines acknowledge and recommend interventions related to race, racism, discrimination, and distrust. Lastly, in some cases, the guidelines did not provide su cient detail to understand all aspects of a given recommendation. We used an iterative two-reviewer process to discuss recommendations that were challenging to categorize using the NASEM framework, but it is possible that some of the 243 references to SDH may have been miscategorized. We do not believe that this would change overall ndings of this review.
Despite these limitations, to our knowledge, this is the rst scoping review to use the NASEM framework on social care activities to gauge the translation of SDH science into clinical care disease guidelines. We found a wide range of social care recommendations in clinical guidelines on the prevention, treatment, and management of hypertension in adults. But the lack of consistency in these guidelines about social care signals that the evidence on these activities is not yet su ciently developed or mainstream. More attention should be paid to strengthening research in this area, including efforts to assess patients' social risks and to intervene on identi ed risks to improve hypertension prevention and treatment. As this evidence grows, future guidelines will need to ensure both speci city and actionability of new recommendations about social care to facilitate implementation.
In a recent article highlighting gaps between hypertension guidelines and clinical practice, Jennifer DeVoe writes, "Where was the evidence-based guideline to answer [the patient's] questions about whether spending money to buy this medication was more important than buying the healthy foods [the care team] had also recommended?"(69) Our review underscores DeVoe's point: existing guidelines fail to provide clinicians with comprehensive, actionable, evidence-based guidance on how to integrate our growing knowledge about SDH into patient care. Attending to a patient's housing, nancial situation, and food security should not leave clinicians feeling like they are providing suboptimal hypertension care. Improving hypertension outcomes and decreasing hypertension disparities will require that the health care delivery system more systematically incorporate SDH-related interventions into hypertension management; the what, when, and how of those interventions will need to be more explicitly incorporated into future guidelines to help scale effective programs. Author contribution: NR and LG designed and conducted the analysis and writing of the manuscript. DH and KB contributed to the interpretation of data and critical revisions of the manuscript. All authors have approved the contents of this paper.  Table 2: De nitions of health care system activities that strengthen social care integration and number of guidelines including health care activities related to social care, by category PRISMA inclusion ow diagram. Reasons for exclusion: Pediatric n=13; Non-essential hypertension (pulmonary hypertension, intracranial hypertension, poral hypertension, radiology ndings, renal hypertension, intraabdominal hypertension n=37; Outside of US guidelines n= 6; Pregnancy n= 10) ;4 were not guidelines. † Unable to locate 3 guidelines; 11 excluded because a more updated guideline existed.

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