Asthma in African Americans: What can we do about the higher rates of disease?
ABSTRACTAfrican Americans not only have a higher prevalence of asthma than whites, they also are encumbered with higher rates of asthma-associated morbidity and death. Factors such as genetics, socioeconomic status, health maintenance behaviors, air quality, and obesity likely contribute in combination to these burdens. Further work is needed to better understand these complex risk factors. To remedy these disparities, we need to ensure that patients at higher risk are given proper care and the knowledge to control their asthma.
KEY POINTS
- To better identify those at risk, researchers are looking at genetic markers such as polymorphisms in ADRB2 and CD14.
- Exposure to tobacco smoke and to cockroach allergen contribute to higher rates of asthma prevalence and morbidity.
- African Americans are more likely to receive suboptimal care, in particular to be misdiagnosed with other conditions, to not receive inhaled corticosteroids, and to not receive proper follow-up.
- Better physician-patient communication is one of the keys to improving this problem.
Ancestry-informative markers
A developing strategy to assess the differences in asthma prevalence, severity, and response to treatment between racial groups is the use of ancestry-informative markers (AIMs).
AIMs are single-nucleotide polymorphisms that occur in varying allelic frequencies between ancestral groups, eg, continental Africans or European whites.21 AIMs provide an estimate of an individual’s proportion of ancestry—ie, of how “African” an African American is genetically.
African ancestry, determined using AIMs, was found to be associated with asthma in people living on the Caribbean coast of Colombia.22 However, one study found that AIMs could not predict an individual’s response to inhaled corticosteroids.23
Further research is necessary to find a technique to determine how groups of individuals can be characterized more precisely and managed more appropriately.
SOCIOECONOMIC FACTORS
African Americans living in low-income urban areas have an even greater prevalence of asthma and a greater risk of asthma-related morbidity and death than African Americans overall.3,24,25 Urban areas typically have a high proportion of residents living at or below the poverty level, and minorities often constitute a substantial proportion of the population in these areas. Evidence suggests that both African American race and lower socioeconomic status are independent risk factors for asthma prevalence, morbidity, and death.3,25
To provide better care for African Americans living in low-income urban areas, it is important to understand the factors that may be contributing to the higher morbidity and mortality rates in low-income urban areas.
Inadequate follow-up
Proper and routine follow-up for evaluation of asthma symptoms is essential for appropriate management. The Expert Panel Report 3 (EPR-3) of the National Education and Prevention Program Guidelines for the Diagnosis and Management of Asthma,26 published in 2007, recommends that patients be seen at least every 6 months if they have been experiencing good control. While gaining control, patients should be seen every 2 to 6 weeks.26
Despite these recommendations, numerous studies have suggested that African Americans do not receive adequate follow-up. Children who are poor, are nonwhite or Hispanic, or are underinsured are more likely to lack routine health care27 and, more specifically, routine asthma care.28 Low-income patients are also more likely to receive care in a large hospital-run clinic or neighborhood clinic,27,28 where continuity of care may be less than ideal.29 Even among patients enrolled in Medicaid or Medicare, African American children with a primary care provider have fewer asthma visits compared with white Medicaid-insured children.30
Insufficient follow-up care contributes to greater asthma morbidity, resulting in, for example, more emergency department visits for asthma in African Americans.27,31,32
Suboptimal care
Data also suggest that the quality of care that residents of low-income urban areas receive is often suboptimal. Many people living in low-income urban areas are not provided with the knowledge and tools to treat asthma exacerbations at home.33 African Americans are also less likely to be seen by an asthma specialist31,34 as recommended for those with moderate or severe asthma.26
The EPR-3 guidelines also stress the importance of inhaled corticosteroids as the preferred therapy for all patients with persistent asthma. Even after controlling for the number of primary care visits, insurance status, and disease severity, African Americans are less likely to receive a prescription for inhaled corticosteroids, or they receive the same dosage of inhaled corticosteroids in the face of more severe disease.31,33,35,36
The reasons for these differences in treatment are not fully understood but are likely multiple. Lack of access to an asthma specialist and financial or formulary constraints are some of the potential barriers to optimal asthma care outcomes.
Misdiagnosis in the acute setting may also be a source of less-than-ideal care, as patients seen in emergency departments may be misdiagnosed with viral infection or bronchitis.
African Americans may report different symptoms than whites
Intriguing studies suggest that African Americans report different symptoms while describing asthma exacerbations.
In one study, compared with whites, African Americans were less likely to report nocturnal symptoms, dyspnea, or chest pain during exacerbations.37 In another study, when given a methacholine challenge that induced a significant drop in forced expiratory volume in 1 second (FEV1), African Americans with asthma were more likely to complain of upper airway symptoms as opposed to lower airway symptoms, compared with white patients.38
The symptoms that African Americans describe, such as having a tight throat or voice, are not typically regarded as related to asthma; for this reason, such descriptions may be an obstacle to correct diagnosis, management, and follow-up.
Asthma care providers should be aware of these observations to ensure that their patients are managed appropriately.
Lack of social support
Living in a low-income urban area presents many challenges that can interfere with proper asthma control.
Asthma diagnosis, management, and morbidity are affected by family support.39 Patients with asthma who lack sufficient financial support for treatment, who lack adequate psychological support, and who have more major life stressors are at higher risk of untoward outcomes. Disruption and dysfunction of the family and the supports available have been associated with greater asthma morbidity.40–42 Unfortunately, these types of stressors are all too common in families living in low-income urban areas.43–45
Multiple stressors that can occur more often in low-income urban areas, including exposure to violent crime, have also been linked to greater asthma morbidity.45–47
POOR PHYSICIAN-PATIENT COMMUNICATION
A consistent theme in focus groups of African Americans living in inner-city areas is the perception that health care providers are not effectively communicating and taking the time to listen to their concerns.48,49 Respondents believed they had better insight into their illness than their providers, and for this reason were better able to manage their disease.
The importance of an optimal provider-patient relationship was highlighted by a prospective cohort study in which Medicaid children receiving care at physician’s offices with the highest cultural competency scores were more adherent with their asthma controller medications.50
