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* Department of Epidemiology and Public Health, Yale University School of Medicine, New Haven, Connecticut
Agency for Healthcare Research and Quality, Center for Primary Care Research, Rockville, Maryland
Departments of Pediatrics and Social and Behavioral Sciences, Boston University Schools of Medicine and Public Health, Boston, Massachusetts
| ABSTRACT |
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Methods. The Childhood Asthma Severity Study provided 12-month, retrospective, parent-reported questionnaire data on a monthly basis for children ages
12 years in a community sample of 1002 children and their families from Connecticut and Massachusetts. Medications considered included cromolyn, ß2-agonist, inhaled steroids, anticholinergics, theophylline, and systemic steroids. Information was available on demographics, insurance status, symptom severity, primary care contact, and provider practice types.
Results. Black and Hispanic children received fewer ß2-agonists, and Hispanic children received fewer inhaled steroids than white children after adjusting for patients race, age, gender, insurance status, symptom severity, number of primary care visits for asthma, number of urgent visits to the regular provider, family income, maternal education, and site of care. When multivariate analyses were restricted to patients in private practice, the significant association between Hispanic ethnicity and low inhaled steroid use persisted, whereas differences in ß2-agonist use by race and ethnicity changed little but became nonsignificant.
Conclusion. Even within private practices, patients race and ethnicity are associated with clinician nonadherence to national guidelines. Programs to eliminate these disparities will need both to focus on site of care and to intervene at the provider and patient levels to be successful.
Key Words: asthma child practice guidelines health insurance Hispanic Americans
Abbreviations: HMO, health maintenance organization CHAS, Childhood Asthma Severity Study
| INTRODUCTION |
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The undertreatment of asthma among racial and ethnic minorities is well-documented.16 Among racial and ethnic minorities in the United States, asthma treatment has 2 consistent and enduring characteristics: 1) lack of access to treatment and 2) health care inconsistent with the guidelines of the National Asthma Education and Prevention Program of the National Heart, Lung, and Blood Institute.1620 For example, studies have documented that minority children are more frequent users of reliever medications such as short-acting ß-agonists and not control therapies such as inhaled antiinflammatory medications.1720 In addition, data from the National Health and Nutrition Examination Survey III, a survey of the US population, reported that young, poor, and Spanish-speaking children were at high risk for inadequate asthma therapy.21 A cross-sectional study of inner-city children who were from Washington, DC, and Baltimore, Maryland, and had at least mild persistent asthma found that these children were high nebulizer users of ß-agonists but low users of inhaled steroids.22
Asthma medication utilization disparities have been reported in situations in which racial and ethnic differences in access barriers should be minimized. Joseph et al23 reported that among children with asthma in a Michigan health maintenance organization (HMO), black children received fewer prescribed medications than white children when seeing nonspecialists. Finkelstein et al9 reported that minority children who had been hospitalized for asthma were less likely than their nonminority hospitalized peers to have received effective preventive asthma therapy; however, after adjusting for primary care practice types, race was no longer a significant factor. Children in their study who were seen by private practice physicians were more likely to receive appropriate care based on practice guidelines than those treated in public settings. The notion that practice type is associated with the delivery of care deemed appropriate by national guidelines has also been reported by Flores et al,24 who found that clinical practice guideline use was more common among pediatricians who practiced in HMOs than in other settings.
Data from the Childhood Asthma Severity Study (CHAS), a community-based study of childhood asthma among a racially and ethnically diverse population, offered the opportunity to evaluate racial and ethnic differences in asthma treatment patterns. CHAS provides sufficient information to allow the evaluation of the importance of site of care and other potential explanatory variables for the reported racial and ethnic differences in asthma treatment patterns. We sought to determine whether differences in medication use by site of care and race and ethnicity persist after adjusting for previous patterns of health care use, insurance status, and symptom severity. The goal of this study was to determine whether the well-reported racial/ethnic differences in asthma treatment are mediated by site of care.
| METHODS |
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Independent Variables
The independent variables were race and ethnicity, age (in years), number of scheduled visits for asthma to the regular provider in the previous year, number of urgent asthma visits to the regular provider, symptom severity (described below), insurance status, family income, maternal education, childs gender, and practice type (described below). Childs race/ethnicity was determined by parental reports and classified as white, black, and Hispanic (93% of the Hispanics reported being of Puerto Rican descent). Family yearly income was categorized as 0 to $19 999 (n = 274), $20 000 to $39 999 (n = 147), and
$40 000 (n = 507). Maternal education was classified as less than high school or equivalent (n = 154), high school or equivalent (n = 261), and more than high school or equivalent (n = 575). Child gender was classified as male (n = 591) and female (n = 350).
The insurance information (private, Medicaid, no insurance) was collected through a supplemental telephone questionnaire. There were 808 respondents to the insurance supplement. Because only 4 participants were reported as not having any health insurance, we restricted the variable to Medicaid (n = 216) and private insurance (n = 588).
Respondents were asked whether their children had regular sources of care, which everyone answered affirmatively. Respondents were also asked to provide the names and locations of the regular providers. From the respondents information, we were able to determine practice types by referring to the Folios Dictionaries for Connecticut and Massachusetts (1998 and 1999).27 We used the practice type classification provided by the dictionaries. Thirty-five (3%) of the respondents did not provide names or addresses, 247 (25%) provided names but the names and practice information were not located in the dictionaries, and 720 (72%) provided names or addresses that were found in the dictionaries. We were able to determine practice types using the dictionaries when we had the provider name, clinic name, or address. Of the 247 participants who provided names or addresses but the names or addresses were not located in the dictionaries, we were able to classify 153 of them into a practice type on the basis of just the information provided. Thus, we had a total of 873 participants who were categorized into a practice type. Practice types were collapsed into the following 4 categories: ambulatory care center, private arrangement, hospital-based clinic, and unknown.
The validity of our symptom severity measure has been reported elsewhere.25 The symptom severity measure is a 9-point score constructed using 4 self-reported questionnaire items, each measured using 3 categories of symptom duration (none, 129 days in last year, and
30 days in the last year) for each of wheezing, coughing, shortness of breath, and chest tightness. For each participant, a symptom severity score was computed by summing across the symptoms using the following point distribution: none, 0 points; 1 to 29 days in last year, 1 point; and
30 days in last year, 2 points. The range was 0 to 8 (mean: 3.3; standard deviation: 2.1).
Dependent Variables
The medication use variables were aggregated to limit the potential for misclassification as a result of recall bias. The cutoffs of the categories were based both on the distribution of the data and on preliminary tests of proportional odds that showed no qualitative differences when using similar cutoffs. The variables were categorized as follows: 1) for each cromolyn, ß2-agonists, inhaled steroids, and systemic steroids, the categories were "none in the last year," "used 1 to 29 days," and "used
30 days"; 2) for both anticholinergics and theophylline, the categories were "none in the last year" and "ever used in the last year."
Analysis
Quantitative differences in the independent variables by race (black, white) and Hispanic ethnicity were determined by
2 for categorical and F test for continuous independent variables. We also compared medication use by site of care (ambulatory care center, private arrangement, and hospital-based clinic) and race and ethnicity using
2.
Fitting of the multivariate models was based on both conceptual and empirical considerations. Each model was adjusted for race/ethnicity, age, gender, insurance status, symptom severity, number of scheduled visits for asthma to the regular provider in the last year, number of urgent visits for asthma to the regular provider, and practice type.
To test the multivariate effects of race on use of cromolyn, ß2-agonists, inhaled steroids, and systemic steroids, we used ordered logistic regression in SAS because the categories of these dependent variables were more than binary.28 Each model was tested for and satisfied the proportional odds assumption. For anticholinergics, we used unconditional logistic regression for binary-dependent variables because the coding was dichotomous. Because a small number of participants used theophylline, we chose not to analyze that medication in a regression model.
To understand the influence of practice type on racial/ethnic disparities in asthma treatment, we fitted a model for ß2-agonists and inhaled steroids for children in private practice. We could not separately analyze the "other" category of practice type because of the small subsample size.
| RESULTS |
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Table 1 lists the summary statistics for sociodemographics, insurance status, practice type, health care visits, and symptom severity by race and ethnicity. White children were more likely to have private insurance, have families that earned
$40 000/year, have mothers with more than a high school education, have been seen in private clinics for regular care, have more scheduled asthma care visits to their regular providers, and have fewer urgent care visits than black and Hispanic children. Black and Hispanic children were more likely to be seen in ambulatory care centers or hospital-based clinics than were white children. There were no differences in age, gender, or reported symptoms.
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30 days compared with those in ambulatory care centers (7%) or hospital-based clinics (7%). Furthermore, a smaller percentage of children in hospital-based clinics used inhaled steroids for 1 to 29 days than those in ambulatory care centers or private arrangements.
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30 days. Overall, a large proportion of children had not used inhaled steroids in the past year: 73% of white children, 88% of black children, and 94% of Hispanic children.
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| DISCUSSION |
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The influence of site of care on medication use is a well-reported phenomenon and can operate through a number of pathways. Rust et al29 reported that community health centers are generally unable to provide quality asthma care to traditionally underserved populations because of a lack of adequate resources. Flores et al24 reported that adherence to practice guidelines was more common in HMOs than in other settings. Other studies have identified provider factors such as imperfect pediatric conformity to clinical practice guidelines, particularly in community- or hospital-based clinics.17,30,31
Our findings add to the previous work by Finkelstein et al,9 who reported that among hospitalized minority children, attendance at nonprivate practice sites of care explained the undertreatment noted in these children before their hospitalization. In the CHAS community sample, nonprivate practice sites were associated with less optimal care, as shown by the lower use of inhaled steroids in the current analyses (Table 2). However, attendance at a private practice site did not ensure that a minority child would receive treatment equivalent to that of a white child.
Our analyses suggest that the relationship between race/ethnicity and asthma medication utilization is mediated through a number of pathways. Simply upgrading the quality of asthma practice patterns at community clinics and hospital outpatient departments will not solve the problem. The association between race and ethnicity and asthma medication utilization will require additional exploration of the patient-physician interaction. In particular, it would be useful to explore the links among the provider, the family, and the system factors associated with disparities in medication use between minorities and nonminorities. A recent article by Mansour et al32 provided some guidance in this regard. The authors reported that among children who had asthma and living in urban areas, the most commonly cited barriers to care were related to patient and family characteristics, health beliefs, and social and physical environments, in contrast to access to health care, health insurance, or continuity of health care.32 Our findings support and extend the findings of Mansour et al because we found that after controlling for primary care contacts, disparities in asthma medication use still exist. Thus, future studies should consider going beyond studying issues of access and focus on parental perceptions and motivators for health care use. Recent studies have also shown that family/maternal factors such as life stressors and poor maternal mental health are associated with poor asthma morbidity and underuse of asthma medications.33,34 Thus, the extent to which poor asthma medication adherence could also be attributable to family stressors should also be explored.
Particular strengths of this study include use of a community sample (rather than a hospital-based sample) of healthy children; consideration of a sociodemographically diverse population of children; and access to a range of questions that deal with not only race and medication use but also primary care contacts, symptomatology, practice teypes, and insurance status. The limitations of this study should also be acknowledged. A limitation of our approach is that it did not identify the differences that might exist in medications according to income level and mothers education within the black and Hispanic groups in private arrangements. Our multivariate model adjusted for this across all categories, ignoring the question of possible differences between groups. Our decision to include these factors in the multivariate models reflects our desire to remove their potential confounding effects in those analyses. For understanding the influence of income and education within the private practice, additional analyses, which would involve dividing up the small minority sample within the private practice group into even smaller groups, must be performed. Given the sizes of our stratified samples, it is not possible to perform these required analyses and obtain reliable/precise results. This was confirmed when we fitted separate models that examined the independent effects of income and maternal education on medication use within the black and Hispanic strata. The analyses were underpowered, which was indicated by very wide confidence intervals.
Other limitations include the following. First, it is unknown in this study whether the children who did not take medications did so because they were not prescribed, their families could not afford them, or they were prescribed and affordable but the family failed to fill the prescriptions. Second, the use of retrospective baseline data reported on a month-to-month basis could introduce recall bias; however, our utilization measures were categorized to limit the potential for misclassification as a result of recall bias. Third, our sampling frame at both the hospital and patient level is a convenient one, but with respect to our variables of interest, there is little reason to suspect sampling bias, because we accessed our sample through the birth of a sibling. Fourth, because of limited sample sizes, we were unable to analyze medication use in practice types other than private. Fifth, we had very limited measures on perceived or actual access to care. Thus, we do not know the extent to which the children could not access needed services.
Ending racial/ethnic disparities in asthma treatment will not be simple. Broad-based changes will be needed. Structural changes, which upgrade the resources and practice patterns of community health clinics and hospital outpatient departments, are a necessary start. However, these initiatives alone will reduce but not eliminate the disparities. More work needs to be done to understand the cultural differences that influence how asthma is perceived, acceptance of treatment, and communication with providers. Finally, providers must be better trained to deal with the changing challenges of their increasingly diverse practices.
| ACKNOWLEDGMENTS |
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| FOOTNOTES |
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Reprint requests to (A.N.O.) Yale University School of Medicine, Department of Epidemiology and Public Health, Division of Health Policy and Administration, 60 College St, New Haven, CT 06520-8034. E-mail: alexander.ortega{at}yale.edu
This article does not necessarily represent the policy of the Agency for Healthcare Research and Quality (AHRQ). The views expressed are those of the authors, and no official endorsement by AHRQ is intended or should be inferred.
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