Update on Underrepresented Populations in Headache Medicine: What Is Known and Care Considerations

Health disparities are preventable differences in the prevalence and severity of disease or treatment that are rooted in social inequalities and linked with social, economic, or environmental disadvantages.¹ They exist in all aspects of general medicine and specialty care; headache medicine is no exception. The symptoms experienced by an individual with migraine contribute substantially to disability, making a normal level of functioning impossible, which is the reason for its designation as the second cause of years lived with disability worldwide as determined by the 2016 Global Burden of Disease Study.²

People from all backgrounds experience migraine. This raises several questions: Are there individuals who are unable to receive a timely and accurate headache diagnosis? Is the availability of care for individuals with headaches and migraine disparate compared with the burden of these diseases in the United States? What factors contribute to and how can we ameliorate the root causes of these issues to establish headache care equity? Answering these questions involves elucidating social determinants of health.

Social determinants of health are conditions in the environment where people are born, live, learn, work, and age as well as the broader set of forces and systems shaping the conditions of daily life that affect a wide range of health, functioning, and quality-of-life outcomes and risks.^3,4 These include individual, family, community, economic, social, and political forces and systems. In people with migraine or other headache disorders, the interplay of these forces has been shown to affect health outcomes. People with a lower socioeconomic status or who are from a marginalized race or ethnicity, have a lower educational level, experience food insecurity, or have lived adverse childhood experiences have been found to have worse health outcomes.⁵

There is a framework that groups social determinants of health into 5 domains (economic stability, education access and quality, neighborhood and built environment, health care access and quality, and social and community context).⁹ In addition, there are socially constructed or established identities and structural determinants of health (ie, age, race, ethnicity, gender identity, sexual orientation, religion, disability, social location, implicit biases) that drive health disparities in headache and migraine by exerting influence over self-management choices, access to care, type of care received, and research.⁶ All these domains and identities are intertwined and directly correlated with health outcomes. The intersectionality among these characteristics can influence health outcomes by compounding their seemingly protective or harmful qualities, which are not based on intrinsic biological value, but rather on external influences.⁵ Furthermore, there is a paucity of research on health care disparities and the effect of social determinants of health, which can be construed as an additional determinant of health that negatively affects groups that are not included.

In a community that values the scientific method to help answer questions about health and diseases, an intentional move that incorporates research and clinical focus on social determinants of health stands to improve how migraine and other headache disorders are identified, documented, and treated. Examining health and health care practices with a lens that incorporates intersectionality will allow for an accurate, thorough, and holistic approach to optimal health and health care outcomes. To that end, in 2020, the National Institute of Neurological Disorders and Stroke sent out a request for information soliciting input on areas of health disparities and inequities in neurologic disease or care in the United States across the lifespan to reveal knowledge gaps, health and research needs, and opportunities for research on health disparities and inequities in neurologic diseases and disorders,^5,7 validating the fact that examining social determinants of health and addressing health care inequities are essential.

The individuals existing within the realm of health disparities are often interchangeably referred to as underserved or vulnerable, given the inequitable care experienced by these groups. Categories of social determinants of health that serve as precursors to disparities for both groups include an individual’s race, ethnicity, gender identity, sexual orientation, socioeconomic status, or geographic location of residence. There is a distinction between the terms underserved or vulnerable, however: vulnerable communities harbor or experience additional circumstances that serve as barriers, exacerbating health inequity.^8,9 For example, an individual may have an ethnic background considered to be part of an underserved community, but may have the knowledge or financial means necessary to receive adequate care, making that individual not vulnerable. If that person, however, does not speak the same language as the health care provider and is not provided with adequate language interpretation, then that individual will be considered vulnerable,⁹ because of the additional obstacle to obtaining equitable care. Therefore, when identifying potential barriers to care, an individualized approach is always necessary, and assumptions always need to be avoided (Table).

Known Headache Medicine Disparities

Contributors to headache medicine disparities include race and ethnicity, gender identity, sexual orientation, socioeconomic and insurance status, and geography. Whereas disparities in headache care of children, adolescents, and elderly people exist, discussion of these special populations is not the focus of this article.

Race and Ethnicity

Population studies reveal that the US prevalence of migraine disease is roughly equivalent in the Black (15%), White (15.5%), and Hispanic (14.9%) populations, with the highest prevalence among American Indian and Alaskan Native (19.2%) populations.¹⁰ Despite the observed equivalence, differences in care access and treatments exist among these groups.

Black (25%) and Hispanic (50%) people are less likely to receive a migraine diagnosis as compared with White people.¹⁰ In headache medicine subspecialty clinics, Black people are less likely to receive a primary headache diagnosis compared with White people, and report higher burden of disease, including higher burden of allodynia,¹¹ increased level of pain intensity, more monthly headache days, and a reduced quality of life.¹² Despite a reported greater burden of disease, of people presenting to medical clinics, Black people were found less likely to present for care as compared with White people (46% and 72%, respectively). During clinic visits, Black people were also less likely to be prescribed an acute migraine therapy in comparison with White people (14% vs 37%).¹³ In the emergency department setting, Black people presenting with a chief complaint of headache were 4.8 times less likely than White people to receive CT imaging for headache evaluation.¹⁴

A 2002 population study revealed that Hispanic people were less likely to seek consultation for pain by a primary care provider (70%) as compared with White (84%) or Black (85%) people; associations included speaking Spanish and having low income. In fact, having Hispanic ethnicity was a predictor for low access to care for chronic pain.¹⁵ Not only are Hispanic people 50% less likely to be diagnosed with migraine compared with White people,¹⁶ they are also less likely to receive adequate prophylactic treatments in US ambulatory care settings.^17-19

Data regarding headache disorders and their effect on the Asian American community are sparse. However, the prevalence of migraine disease or severe headache in Asian American people (unspecified ethnic subgroups) was noted to be 11.3%¹⁰ in 2018.

In addition to having the highest reported prevalence of migraine disease and severe headache attacks, American Indian and Alaskan Native people were noted to experience more allodynia in a 2008 population study.¹¹ More studies are needed to elucidate challenges in this population.

Sexual Orientation and Gender Identity

The true prevalence of headache in members of sexual and gender minority (SGM) groups is unknown, as data are limited. However, recent studies suggest a higher prevalence of migraine in SGM individuals. In 2020, the prevalence of headache/migraine was the highest among bisexual women (36.8%), followed by lesbians (24.7%), bisexual men (22.8%), heterosexual women (19.7%), gay men (14.8%), and heterosexual men (9.8%).²⁰ Another study found the prevalence of migraine to be higher in lesbian, gay, or bisexual individuals compared with heterosexual individuals.²¹ Before these prevalence studies, research revealed transgender women on estrogen to have a prevalence of migraine similar to that of cisgender women (26%); of those, 54% had aura.²² As interest in headache care of SGM individuals has grown, a more recent small Turkish-based cross-sectional study revealed that in a sample of 88 transgender men, 36.4% had migraine and 40.9% had tension-type headache.²³ Another study suggests that SGM individuals with a history of discrimination and trauma had more significant disability from migraine.²⁴ It is likely that headache, specifically migraine, is common in the SGM population, and may confer more disability, based on the data.

Socioeconomic and Insurance Status

Providers caring for underserved communities do not have to look far to witness the effects of socioeconomic and insurance status on health care access. Low socioeconomic status is a known independent risk factor for worse health outcomes.²⁵ Migraine prevalence is strongly associated with annual household income; lower income groups (<$10,000) have been shown to have a more than 60% higher prevalence of migraine than higher income groups (>$30,000).²⁶ One of the barriers identified to receiving timely headache consultation, appropriate diagnosis, and treatment is not having insurance.²⁷ Low-income earners and uninsured people tend to visit emergency departments for care. Uninsured people with migraine, or those with Medicaid, are 2 times less likely to receive acute medication and 1.5 times less likely to receive preventive medication compared with commercially insured people.²⁸ Given that ineffective treatment is a risk factor for transition of migraine disease from episodic to chronic,²⁹ those with low socioeconomic status and lacking insurance are considered vulnerable in the realm of headache care.

Geography

Area of residence or environment in which one lives can also affect care opportunities. Highly subspecialized care such as headache medicine may lend itself to variable care options in one location vs another. For example, more headache medicine training programs are situated in urban areas, with a higher number of headache specialists tending to remain in those areas after training.³⁰ Therefore, people who live in rural settings are vulnerable to not receiving a timely diagnosis, worsening disease, longer wait times for care, travel inconveniences, and higher disease-related income losses and expenses.³⁰ Professional organizations, such as the American Headache Society, have been working to educate non-neurologists and non–headache specialists about headache management and treatment to address these care gaps.

Disparities in Clinical Trials and Research

Individuals from minoritized backgrounds historically have been underrepresented in clinical trials. This may be attributable to several factors, including mistrust of the medical field owing to historic exploitation in research, stigma, and researcher factors such as implicit bias and stereotyping people from underserved ethnic and racial groups.^31,32 Individuals from minoritized backgrounds may have reduced access to a subspecialist or less utilization of health care because of socioeconomic factors, which can result in a reduced opportunity to participate in trials.³² Other barriers to participation of underserved groups in clinical trials include poor trial design, inappropriate exclusion criteria (ie, a blanket exclusion of all women of childbearing age), costs associated with interpretation of data, consent issues related to language, and shortage of ethnically diverse trial coordinators.³²

Current studies in migraine are not representative of certain populations, which affects external validity and generalizability. A 2017 study reviewing randomized controlled trials in migraine found that only 25 of the 36 trials included reported the racial composition of the participants, and none of the studies reported the results stratified by race or sex. No studies reported the race or sex of those who experienced adverse events. Of the trials that were included, 84.5% of the participants were women, and 82.5% were White. Compared with the US population, trials included fewer men and fewer non-White individuals.³¹

It is imperative for underserved and vulnerable individuals to be included in headache clinical trials, as diversifying study participants will allow for a better understanding of pharmacogenomics and its role in migraine treatment, leading to better, more culturally competent care. Community engagement throughout the entire research process is crucial, as it allows researchers to include diverse community members and groups in study design, participant recruitment, retention, and analysis. With community participation, researchers can better assess and develop outreach programs and interventions to meet community needs. This type of research—community-based participatory research—increases representation within studies, improves research quality by enhancing study design and protocol for informed consent and data analysis, and facilitates dissemination of study results to said community.^33,34 Researchers also should maintain a regular practice of examining their own implicit and explicit biases, and aim to address psychosocial factors such as stigma, discrimination, and microaggressions, to aid in recruiting and retaining diverse participants in clinical trials. Effective communication throughout the research process is crucial; researchers should use accessible language that is educational and clear and allow for interpreters or non-English materials to be used to ensure proper informed consent and explanation of research aims and results.³³

Conclusion

This article provides a brief discussion of recognizing and caring for underserved and vulnerable communities in headache medicine. The factors that contribute to health care disparities are complex, multifaceted, and often involve sensitive subject matter. People and providers may be hesitant to discuss these matters because of real or perceived lack of knowledge or understanding, medical illiteracy, cultural illiteracy, implicit or overt bias, or lack of resources that can help overcome the barriers to equitable care. Recognition is the first step to tackling headache disparities, followed by mitigation strategies, which require continued open dialogue and collaboration. Table 1 depicts common barriers and pitfalls to headache and migraine care of underserved and vulnerable populations. The resources provided are initial steps providers can take in hospital or clinic interactions to address these barriers.