Partners Asthma Center Grand Rounds
George T. O'Connor, M.D.
Special Challenges Posed by
Data on the estimated nationwide prevalence of asthma indicate a progressive increase in asthma prevalence in the United States between 1980 and 1994. This increase is especially perplexing when one considers that our most effective preventive therapies for asthma, inhaled corticosteroids, were introduced into this country in 1979. Many hypotheses have been offered to explain this observation -- from greater indoor allergen exposure in our more tightly sealed houses to fewer childhood respiratory infections to less exposure to endotoxins associated with farm animals. Identifying the reasons for this trend is a fascinating and complex puzzle that will challenge medical scientists for many years to come.
At the same time, another epidemiologic pattern continues to evolve year after year right here in our local neighborhoods: the greater severity — and possibly greater prevalence — of asthma in low-income urban areas. In Boston, as in other major metropolitan areas across the United States, hospitalization rates are higher in low-income communities than in more affluent areas of the city. Data from 1992 found that our inner-city communities, those with the highest proportion of low-income residents, minority residents, and residents with low educational attainment — Roxbury, South End, and parts of Dorchester — had asthma hospitalization rates of more than 5 per 1000 population/year, compared with the statewide average of approximately 2 per 1000/yr (Figure 1). The age- and gender-adjusted asthma hospitalization rate in Brookline was approximately 1 per 1000/yr, compared with approximately 10 per 1000/yr in Roxbury, located just a few miles away. I suspect that we have a better chance of coming to understand this striking local trend in asthma severity and health care utilization than we do the national increase in asthma prevalence.
Understanding excess asthma morbidity in the inner-city
Potential explanations for the excess asthma morbidity observed in the inner-city include genetic, environmental, and healthcare-related reasons. It is possible that certain demographic groups that are over-represented in urban communities have a genetic predisposition to worse asthma. For instance, data from the Hispanic Health and Nutrition Education Survey indicate that Puerto Rican children have approximately four times as much asthma as white children, and they also have approximately four times as much asthma as southwestern Mexican-American children. These data, which find that Caribbean Latinos have more asthma than southwestern Latinos independent of income or Hispanic cultural commonalities, raise the possibility of a genetic basis for the difference. Other studies have found little or no racial differences in asthma prevalence that could not be accounted for by socioeconomic factors, so there remains controversy about the genetic basis for excess inner-city asthma morbidity. On the other hand, there is no debate about the fact that environmental and healthcare-related factors differ in inner-city urban environments compared with other environments.
There are many ways in which the living environment for children and adults in Roxbury differ from that of persons living in nearby Brookline. Aeroallergen exposures are the most obvious, including pets, cockroaches, rodents, mold growing in old buildings, and dust in faulty air supply systems. Rates of cigarette smoking and environmental tobacco smoke exposure are higher. Dietary differences may also prove to be important, both in terms of the development of asthma and its severity.
Recent interest has focused on cockroach allergen, as highlighted by the National Cooperative Inner-City Asthma Study sponsored by the National Institutes of Health (NIH). This study enrolled approximately 1000 inner-city children between the ages of 6 and 12 years with moderate-to-severe asthma and allergic sensitivity (skin test positivity) to at least one indoor allergen. Thirty-six percent of these children were allergic to cockroach. In a cross-sectional analysis of this population, the combination of cockroach allergen sensitivity and high levels of cockroach allergen exposure in the home was associated with a significantly increased chance of having had asthma hospitalizations in the preceding year.
Allergen exposures may not only account, in part, for differences in asthma morbidity, they may also influence disease prevalence. A prospective study of children in England found that more intense dust mite exposure in the home at age one year predicted a significantly higher risk of developing asthma at age 11. A birth cohort in Boston is now being followed to determine whether cockroach allergen exposure within the first few months of life is associated with an increased prevalence of persistent asthma later in childhood. There are potentially very important implications of these study outcomes in terms of housing codes and possibly the development of threshold permissible levels of cockroach allergen (similar, for instance, to federally-mandated permissible levels of ozone in ambient air).
Overall, the conceptual model that we are proposing involves a genetically predisposed person (perhaps more common among Caribbean Latinos), exposed to allergens early in life, perhaps in combination with other factors that influence the competence of the bronchial epithelium such as viral infections and environmental tobacco smoke, who consequently develops asthma. As a result of continued exposure to allergens, viruses, and/or irritants, asthma severity is aggravated. With this model, it is relatively easy to understand that environmental factors encountered in low-income, urban environments might, at least in part, explain why asthma there is definitely more severe and possibly more common.
Differences in healthcare utilization
In 1992 we performed a study that emphasized the impact of differences in utilization of healthcare on asthma hospitalization rates in Boston. We did a small area analysis of communities in Boston looking at the use of preventive asthma medications. We were able to obtain information on medication purchases by zip code from the records of all pharmacies in these communities (excluding hospitals and health maintenance organizations). For each zip code area we created a ratio for the number of prescriptions for preventive medications (inhaled steroids and cromolyn) to rescue medications (inhaled beta-agonist bronchodilators). A high ratio represents more desirable care, reflecting routine use of controller medications and infrequent need for quick-reliever bronchodilators. Our findings indicated an inverse relationship between hospitalization rates and this ratio of medication purchases among 22 Boston communities (Figure 2). The low-income, inner-city community with the highest rate of hospitalization for asthma (Roxbury) had the lowest ratio of anti-inflammatory to bronchodilator medications purchased. The more affluent communities of Kenmore, West Roxbury, and Downtown Boston had the highest ratios.
These results are likely of no surprise to anyone whose practice of medicine involves low-income, inner-city residents. Many persons in these communities have no or inadequate health insurance, little money to buy medications, and no routine ambulatory medical visits for preventive care. At the same time that they have more severe asthma, they have the least favorable pattern of medication utilization to control asthma. Any successful management approach to inner-city asthma will need to involve a major emphasis on getting persons with asthma to use daily controller medications on a regular basis. Under-utilization of anti-inflammatory medications is likely one of the causes of increased asthma morbidity, including hospitalizations, in our inner-cities. We need to make preventive asthma medications accessible, affordable, and properly used.
Management of inner-city asthma
Management of asthma in the inner city poses special challenges as one tries to overcome the financial, cultural, linguistic, and educational barriers to care. Nonetheless, it is worth emphasizing that in the end the management of asthma in the inner city is identical to asthma management elsewhere, only more intensive. One needs to apply the same care strategies as for any patient with asthma, but pursue them more aggressively, because they are harder to implement in our inner-city patients. One example relates to efforts at asthma education, teaching patients (or parents) asthma co-management skills. Published studies describe the benefits of implementing classes for groups of patients or patient families, some involving multiple sessions over time. For the typical patient or parent living in the inner city, day-to-day life is a full-time struggle, with little time left over for scheduled classes. Even getting to one's doctor's appointment is difficult: the rate of missed appointments in my outpatient asthma practice at Boston Medical Center is consistently 50%. For our patients, asthma education has to be one-on-one and where possible incoporated into scheduled medical visits.
Despite these impediments, the potential for developing a highly successful care model for inner-city patients exists, as demonstrated in a published report by Dr. Paul Mayo and colleagues at Bellevue Hospital in New York City. He identified a population of patients with severe asthma, frequent emergency visits and hospitalizations for asthma, and lack of routine ambulatory medical care. He randomly assigned half of these patients to an intensive medical intervention and half, as control group, to routine care. The intensive intervention group received medical care from Dr. Mayo in a Pulmonary Clinic. He was available to these patients, accessible at all times, and made sure that they received their medications. He emphasized routine use of inhaled steroids and early initiation of oral steroids for asthmatic attacks. In short, he utilized a traditional clinician-patient model with an emphasis on continuity of care and appropriate medication use. The outcome of this randomized, controlled trial was dramatic, with significant reductions in hospitalizations and emergency department visits in the active intervention group.
In treating low-income, inner-city persons with asthma, it is important early on to address financial and insurance resources. It makes no sense to write multiple prescriptions for expensive medications if the patient cannot afford to buy any of them. In Massachusetts we are fortunate to have the statewide "free care" program that includes pharmacy benefits. As a result, patients approved for free care have access to any anti-asthmatic medication that might be needed. Nonetheless, the problem remains, such as among persons residing in this country illegally, who may not wish to provide any registration information as part of a "free care" application, and among persons whose health insurance plans do not cover pharmacy costs. It is best to confront upfront this financial barrier to care.
Guidelines for disability due to asthma
A related financial issue is the request for assistance in applying for disability due to asthma. A major goal of asthma therapy is helping patients to achieve normal or near-normal exercise capacity; we try to prevent disability due to asthma. At the same time, some of our inner-city patients with asthma cannot possibly work due to the severity of their asthma. Without income and without health insurance, they are in desperate need of disability compensation. The criteria for disability established by the Social Security Department of the federal government include the following: persons who over the past 12 months, despite therapy, have had 6 or more unscheduled physician visits for asthmatic exacerbations (with one hospitalization for asthma counting as the equivalent of 2 unscheduled visits) or who have irreversible airflow obstruction on pulmonary function testing that meets the Social Security disability critieria for chronic obstructive pulmonary disease (e.g., FEV1 <1.55 L for a person whose height is 5’ 10”). It is important to be familiar with these criteria so that you can assist persons who are truly disabled by their asthma to get appropriate financial aid while at the same time helping those who might wrongly think that they are disabled to get good medical therapy and optimized funtional status.
It is important to inquire about substance abuse. Asthma and substance abuse — particularly crack cocaine and nasal heroin — can be a deadly combination. Asthmatics who use these drugs are sometimes brought to our emergency room with fatal asthma attacks. Even though our resources to treat substance abuse may be limited, asking about it is the first step toward identifying the problem and then trying to get the patient help.
Communication is critically important. At Boston Medical Center all of our staff are bilingual in English and Spanish. We find it particularly important for the receptionist staff and for our nurse educator to be able to communicate effectively with our patients — both in terms of language and cultural sensitivity. One of the ways that we can minimize some of the frustrations of our patients is to have staff who can speak to our patients in their native language and engage them in a supportive way.
Role of asthma nurse case managers
In our asthma program nurse case managers have played a critical role. We are currently engaged in a small randomized trial at the Greater Lawrence Family Health Center to assess scientifically the benefit of nurse case management in asthma care. In the meantime it seems reasonable to anticipate improved outcomes when nurses — or nurse practicitioners or social workers — receive disease-specific training that enables them to help physicians provide care to their patients and help patients to deal with the complexities of their illness and its treatment. Some of the basic elements of asthma case management include the following: teach patients about their medications; assess the home environment and teach environmental control measures; provide patients with asthma action plans; assess asthma control with measurements of lung function (peak flow or spirometry); be familiar with the NIH guidelines for asthma and know when asthma care needs to be "stepped up"; help patients overcome barriers to care; and provide patient advocacy (whether confronting truant landlords or insisting that electrical service not be terminated).
One example of how asthma management in the inner city is the same as asthma management anywhere — just more so — is teaching inhaler technique. A large part of what our asthma nurse does is reviewing inhaler technique at every office visit. We have found the dry-powder inhalers helpful in this regard, since they appear simpler to master and do not require a spacer. We try to simplify medication regimens as much possible, encouraging a schedule of regular preventive medication use no more than once or twice daily.
Another example is the institution of environmental control
measures. We emphasize smoking cessation and avoidance of
second-hand cigarette smoke exposure (getting the parent not to
smoke indoors) and reduction of allergens in the home. While we
can all agree that these measures make sense, their exact impact
on asthma morbidity in the inner city remains to be determined.
We are currently participating in an NIH-funded multicenter trial
that is evaluating the impact of a home environmental
intervention in seven U. S. cities. The study population consists
of inner-city children aged 6-12 years with moderate-to-severe
asthma and at least one positive allergy skin test. Half of the
nearly 1000 children enrolled are randomly assigned to the home
The intervention consists of our team of two enviromental counselors making 6-7 home visits over the course of the year. We provide the caregivers with a lot of information about how to make their homes a more asthma friendly environment, with an emphasis on allergens and passive smoking. We also give the caregivers a vacuum cleaner with high-efficiency particulate air (HEPA) filter, a HEPA air filter for the child's bedroom, cleaning supplies, and a year of professional pest control service. The entire cost of the intervention is approximately $1000 per family. It is our hope that at this cost, the intervention, if successful, could potentially be widely implemented by a variety of healthcare organizations.
Sporik R, Holgate ST, Platts-Mills TA, Cogswell JJ. Exposure to house-dust mite allergen (Der p I) and the development of asthma in childhood. A prospective study. N Engl J Med 1990; 323:502-7.
Gottlieb DJ, Beiser AS, O'Connor GT. Poverty, race, and medication use are correlates of asthma hospitalization rates. A small area analysis in Boston. Chest 1995; 108:28-35.
Mayo PH, Richman J, Harris HW. Results of a program to reduce admissions for adult asthma. Ann Intern Med 1990; 112:864-71.
About the Author: Dr. George O'Connor is a member of the Division of Pulmonary, Critical Care, and Allergy at Boston Medical Center, where he directs their Asthma Center. He is trained as an epidemiologist and is currently a participating investigator in the multicenter Inner-City Asthma Study of the National Institutes of Health. He is Associate Professor of Medicine at Boston University School of Medicine.