Disparities in sleep care and cardiovascular outcomes: defining the problem and implementing solutions

OVERVIEW

A session on the effect of disparities in sleep care on cardiovascular outcomes was held at the 2023 American Academy of Sleep Medicine meeting. Each speaker briefly introduced topics followed by an interactive discussion among the audience and panelists. Here, we summarize the discussion points raised during this session.

BACKGROUND

Racial disparities in sleep health are a key driver of cardiovascular (CV) disparities. The National Institutes of Health defines health disparity as a “health difference that adversely affects disadvantaged populations in comparison to a reference population.”¹ Black individuals have a greater risk of CV mortality and morbidity than other racial and ethnic groups in the United States.² Increasingly, sleep disorders and insufficient sleep are being recognized as contributors to CV risk.³ In particular, African American (AA) individuals are disproportionately affected by obstructive sleep apnea owing to underdiagnosis, a lower rate of referral to sleep specialists, and a lower acceptance of continuous positive airway pressure therapy as a first-line treatment compared with White individuals.⁴ There are also disparities in other sleep conditions such as insomnia, which are partly attributed to social determinants of health. For example, a recent study showed that in the suburbs surrounding Chicago, Illinois the average sleep duration of AA was nearly 1 hour shorter than that of White adults.⁵ With the recent expansion of the American Heart Association’s Life Simple 7 to the Essential 8 with the inclusion of sleep, we are further understanding the contribution of sleep to CV outcomes and disparities.

PHYSIOLOGICAL ASPECTS OF RACIAL DIFFERENCES IN CARDIOVASCULAR SLEEP HEALTH

Race and ethnicity play an essential role in shaping sleep and CV health. AA adults experience higher rates of CV disease (CVD) compared with other racial groups.⁶ Also, AA adults are more likely to have a rapid increase in arterial stiffness at younger ages and maintain higher levels of central arterial stiffness throughout their lives in comparison to their White counterparts.⁷ In addition, impaired vascular vasodilator capacity and heightened vascular responsiveness have been suggested as the potential physiological mechanisms that explain the greater CV risk in this population.⁸ Similarly, different racial and ethnic groups exhibit varying degrees of susceptibilities to CV risk associated with poor sleep. Analysis of the 2008 Behavioral Risk Factor Surveillance System (BRFSS) revealed that whereas the relationship between insufficient rest/sleep over 30 days and CVD was significant across all groups, AA and Hispanic adults faced higher odds of CVD (odds ratio = 2.06 and 2.22, respectively) compared with White adults (odds ratio = 1.62).⁹ Despite limited evidence, emerging research has suggested that the relationship between sleep and CV health differs based on race. Lee et al found that race played a moderating role in the relationship between sleep problems, as measured by a composite score derived from actigraphy and self-reported sleep data, and CVD.¹⁰ The researchers noted that both White and Black races showed a similar moderating impact on this relationship, yet such an effect was not evident among individuals of other racial backgrounds. Additionally, the impact of obstructive sleep apnea on atrial fibrillation was significantly influenced by race, with AA adults at high risk of obstructive sleep apnea showing a 58% increase in odds of atrial fibrillation, vs a 12% increase for White adults.^11,12 These findings collectively suggest that sleep may influence CV health differently by race. However, there is a great paucity of research in this area. More investigations are essential to explore how race and ethnicity modify the way impaired sleep affects CV health.

SOCIAL DETERMINANTS OF SLEEP AND CVD DISPARITIES

As highlighted by the American Heart Association, structural racism exhibited through racist policies such as redlining has led to segregation and concentrated poverty, resulting in differential access to health care, environments, education, and capital.¹³ These social determinants disproportionately affect racially minoritized groups such as Black and Hispanic populations. A large body of research supports that social determinants are associated with adverse sleep and CV health.^14–16 As discussed above, sleep is associated with CV health, through different mechanisms including sympathetic nervous activity, autonomic activity, inflammation, and other physiologic activities. Thus, racial differences in sleep may exacerbate adverse CV health among marginalized populations.

Albeit limited, research studies have demonstrated that sleep may partially mediate racial and ethnic differences in CV health. One of the first studies to suggest sleep as a contributor to CV disparities was conducted using data from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort study.¹⁷ The authors found that sleep duration partially mediated the Black–White difference in the change in diastolic blood pressure. Notwithstanding this observation, sleep did not mediate racial differences in the change of systolic blood pressure. Consistent with these findings, a study conducted in a racially and ethnically diverse sample in Chicago found that sleep maintenance, but not sleep duration, mediated 11.4% of the Black–White difference in hypertension.¹⁸ Among 426 Black and White adults in the Midlife in the United States Study, total sleep time and sleep efficiency separately explained 41% and 56%, respectively, of the Black–White difference in cardiometabolic health.¹⁹ These studies support that sleep may explain racial differences in CV health. Thus, with additional data, intervening on sleep may reduce the burden of adverse CV health among Black adults. Interventions that address social determinants including access to care are warranted.

ACCESS TO SLEEP CARE

A key driver of disparities in sleep care on cardiovascular outcomes is access to sleep care. We define access in this context as the ability to obtain an evaluation, testing, and treatment for a sleep disorder. At each level of the sleep care continuum there are both local factors that limit access to care and broader factors. Local factors that affect sleep care may include neighborhood limitations such as transportation, low socioeconomic status, and housing instability. Broader factors that contribute to adequate access may include racism, mistrust of the health care system, and segregation.¹⁵ Emerging evidence suggests the racial diversity of the physician workforce may affect outcomes in different racial groups. A 2020 analysis showed that at that time the percentage of underrepresented minority pulmonary and critical care medicine fellows had declined to 10.3% of fellows.²⁰ This will undoubtedly be a critical area of investigation and process improvement in the future.

Sleep disorders are less frequently diagnosed in Hispanic/Latinx and AA populations. The Hispanic Community Health Study/Study of Latinos and Jackson Heart Sleep Study show that obstructive sleep apnea is underdiagnosed in these populations.^21,22 Of the AA patients referred for sleep care only 38% of those in a small study presented to the sleep specialist appointment for continued workup of their sleep disorder.⁴ Among patients that do receive positive airway pressure therapy, current payer policies are based on thin medical evidence and are felt to disproportionately affect AA and Hispanic adults.²³ A previous study showed that AA patients used continuous positive airway pressure therapy on average 92 minutes less than Whites.²⁴ Importantly, professional societies such as the American Thoracic Society have started to issue policy statements to reform positive airway pressure thresholds to lower levels so that patients will have the opportunity to have more time to acclimate to therapy and the ability to continue therapy at lower adherence thresholds.²³ Innovation in payer policy is critical to improve adherence and improve cardiovascular outcomes.

There are also barriers to access to care for individuals with insomnia. Cognitive behavioral treatment for insomnia (CBTi) is one such area where there may be disparities in access to care. The annual rate of outpatient mental health service use was more than twice as high in White than in AA populations in a recent review of medical expenditures data.²⁵ Among pregnant patients receiving CBTi, AA women completed fewer treatment sessions and had poorer outcomes from digital CBTi than White women.²⁶ There have been successes with electronic CBTi options that were culturally tailored having more effective participation engagement and proportion of the program completed.²⁷ Another issue remains the digital divide and need for more access to smartphones and internet access for participation in these efforts.²⁸ Optimizing access to mental health services and CBTi is a critical aspect of improving cardiovascular outcomes by improving sleep care.

A STAKEHOLDER-ENGAGED FRAMEWORK TO IMPROVE ACCESS TO SLEEP CARE

Several studies have documented racial and ethnic disparities in adherence to physician-recommended sleep care. However, despite its public health significance, there is a paucity of studies addressing these disparities. There is a lack of health programs and policies to increase screening and treatment of sleep disorders among Black people and other individuals from minoritized populations. A practical framework to increase the number of people screened for sleep disorders and treated appropriately is warranted. Such a framework is of major importance, given that early identification of sleep disturbances in high-risk populations could potentially lead to early treatment and prevention of CVD, thereby reducing racial/ethnic disparities in sleep-related cardiovascular morbidity and mortality.

To address challenges of underdiagnosis and suboptimal treatment of sleep disorders among Blacks, the Sleep Equity Workgroup at the University of Miami has developed a practical stakeholder-engaged framework that includes strategies guiding development of effective interventions to engage communities in the research process and ensure sleep interventions are culturally and linguistically appropriate. The overarching goal of this framework is to (1) increase engagement of Black individuals to participate in screening and treatment of sleep disorders as well as sleep-related research and (2) ultimately improve their cardiovascular health through improved sleep and circadian health.

It is of utmost importance that tailored interventions emphasize the crucial role of the community, because failure to engage stakeholders early in the research process often results in protocols and programs that are ineffective or incompatible with community needs. Although engagement in the development and implementation of interventions can be a complex process and may appear to be beyond the scope of routine clinical practice, it remains an important component of sleep and circadian research. Furthermore, interventions should be designed to advance our understanding of key barriers that should be eliminated and facilitators of sleep care uptake that should be activated to achieve sleep health equity. The workgroup has developed this framework based on our previous community-engaged research undergirded by a synthesis of relevant literature, particularly in community-based participatory research with a focus on Black individuals. Box 1 contains the proposed guidelines for implementing a sleep and circadian health program based on evidence from our community-based interventions. It is our hope that through improving recognition and overcoming of systemic issues that mediate disparities in sleep outcomes (Figure 1), we may together improve the CV outcomes in all patients.

Box 1. Guidelines to implement a stakeholder-engaged sleep/circadian program

1. Identify the partner community: barbershop, beauty salon, places of worship.

2. Establish equitable relationships with the leader of the organization.

3. Recruit credible community health champions to form the implementation team.

4. Use focus groups to guide the implementation process.

5. Publicize risk factors for sleep disorders in community bulletins and media platforms.

6. Encourage stakeholders (eg, barber, stylist, pastor) to support the program.

7. Perform risk screening during scheduled activities (eg, church services).

8. Increase awareness through dissemination of tailored sleep health communications.

9. Refer identified high-risk individuals for further sleep evaluation.

10. Contact participants with a diagnosis to participate in sleep support groups.

11. Encourage participation in weight management programs for risk reduction.

12. Train educators to provide lifestyle guidance and social support to enhance sleep care.

13. Develop culturally and linguistically tailored materials for the partner community.

14. Provide referrals to sleep specialists and monitor impact on access to sleep services.

15. Provide appropriate measures at baseline and postintervention to evaluate success of novel, personalized interventions.

Figure 1. Schematic of how structural racism has contributed to disparities in social determinants of health, which have created disparities in sleep care and cardiovascular outcomes.

DISCLOSURE STATEMENT

All authors have seen and approved the manuscript. This work was funded in part by NHLBI R01HL157954. The authors report no conflicts of interest.