Nebulizer Use in Inner-City Children With Asthma: Title and subTitle BreakMorbidity, Medication Use, and Asthma Management Practices FREE

THE PREVALENCE of asthma, the most common long-term disease of childhood, significantly increased in children aged 5 to 14 years from 1980 to 1994 (42.8 to 74.4 per 1000 children).¹ Children with a history of frequent emergency department (ED) care and hospitalizations are at the greatest risk for reduced quality of life, increased school absences, and life-threatening asthma exacerbations.^{2 - 5} This increased risk is related to young age, poor access to medical care, undertreatment of asthma, and poor asthma self-management.^{4 ,6}

Studies indicate that there is no difference in efficacy between using a metered-dose inhaler (MDI) with a spacer and using a nebulizer for administration of inhaled albuterol to older children with mild to severe asthma. Both devices are the ideal delivery system for inhaled β-adrenergic agonists.^{7 - 14} However, home nebulizer use is favored over MDI use when there is difficulty in coordinating inspiration with MDI actuation, particularly in acutely ill, crying, or dyspneic children with asthma.¹⁵ It is estimated that more than 50% of patients have problems using MDIs.¹⁶

Current National Asthma Education Prevention Program (NAEPP) guidelines¹⁷ recommend nebulizer use for children younger than age 2 years and patients unable to use an MDI with a spacer. Recent trends in asthma care encourage early initiation of home nebulizer use for relief of acute, severe symptoms, especially in young children,^{15 ,18} to decrease ED visits and hospitalization.^{19 - 20}

While there are data describing short-term morbidity in children with asthma using MDIs,^{9 ,11} there are little data describing the morbidity, medication administration, and asthma management characteristics for children using nebulizers and even less data describing inner-city children's use of nebulizers. The objectives of this study were (1) to assess the frequency of nebulizer use in an inner-city pediatric population, (2) to describe the morbidity, pattern of medication administration, and asthma management in children with asthma using a nebulizer compared with children with asthma not using a nebulizer, and (3) to examine potential relationships between inhaled anti-inflammatory medication administration, asthma morbidity, and asthma management practices in children with current nebulizer use.

This study has a cross-sectional design, using data collected from parents or caregivers of children with asthma enrolled in 2 community-based asthma intervention studies in Baltimore, Md, and Washington, DC. The first study (Community-Based Adherence Intervention for African American Children With Asthma) tested the effectiveness of school-based asthma education and community health worker intervention on reducing ED visits, hospitalizations, school absences, and asthma care practices.²¹ The second study (A+ Asthma Partnership for Minority Children With Asthma) examined the effectiveness of a community physician educational program to increase knowledge of asthma management and skills of community physicians and to reduce ED visits and hospitalizations in inner-city children with asthma. Both intervention studies were approved by the Institutional Review Boards of the Johns Hopkins Medical Institutions, Baltimore, and the Howard University College of Medicine, Washington.

Seven hundred thirty children (338 enrolled in Community-Based Adherence Intervention for African American Children With Asthma; 392, A+ Asthma Partnership for Minority Children With Asthma) were included in the data presented in this article. Study participants with a physician diagnosis of asthma were recruited from 42 elementary schools in Baltimore and Washington during September 1992 through June 1996.

Criteria for inclusion were physician-diagnosed asthma based on parent and school health record reports. Of the enrolled children, 60% reported asthma symptoms consistent with mild, persistent asthma or a greater severity of asthma based on the NAEPP guidelines¹⁷ (eg, daytime or nighttime cough or wheeze >2 times a week). Another 29% of these children reported symptoms consistent with mild intermittent asthma (eg, daytime or nighttime cough or wheeze ≤2 times a week). No asthma symptoms were reported by 11% of the children. For each child identified from school records, a short survey was sent home to the parent to confirm that the child had asthma and that the parent agreed to participate in the study. Exclusion criteria included any current participation in other asthma studies. Excluded from this analysis were children with multiple missing data (n = 26) or missing data regarding nebulizer use (n = 5) and children younger than age 5 years (n = 13). These exclusions resulted in a final sample of 686 (94%) from the total children enrolled in both studies.

Baseline study data were obtained via telephone interview after obtaining written parental or legal guardian consent. The 30-minute telephone survey was conducted by professional interviewers from June 1994 through June 1998 to families of children with asthma enrolled in either study. Families without telephones or those who could not be contacted were mailed a card with a toll-free telephone number to call, which linked them to an interviewer who administered the interview. These families were sent a $20 incentive after completion of the interview.

Data were collected using a 170-item baseline questionnaire that included questions in 5 domains: sociodemographic, asthma morbidity, health care utilization (asthma as well as primary care), asthma medication use, and asthma self-care management practices. Nebulizer use was ascertained by asking, "Do you have a nebulizer (a special machine that gives prescribed medicines) in your home for your child's asthma?" and "How many times in the last 30 days did you use the nebulizer (mist machine) for your child's asthma?" Children were defined as a nebulizer user (NU) if they reported use of a nebulizer at least 1 or more days per month during the last 6 months.

Assessment of asthma morbidity included number of symptom (cough or wheeze) days and nights per month in the last 6 months, number of school absences due to asthma in the last 12 months, number of times receiving oral steroids in the last 12 months and past 30 days, and current use of oral steroids. Health care utilization items included the number of hospitalizations in the child's lifetime and in the last 6 months, number of ED visits in the child's lifetime and the last 6 months, and number of physician visits for regular asthma care in the last 12 months. Asthma medication administration was assessed using items asking asthma medication type, frequency of administration, and type of medication administration (oral or inhaled) used presently and during the last 6 to 12 months. Assessment of asthma management included having a regular source of asthma care, peak flow meter use, and receiving allergy skin testing.

Data were summarized by examining frequency distributions for all sociodemographic, asthma morbidity, health care utilization, asthma medication, and asthma management variables for 686 participants. Child participants were categorized either as NUs (use of a nebulizer ≥1 day during the past month) or nonnebulizer users (NNUs) (no nebulizer use or <1 day per month of nebulizer use). Categories of asthma medications were created by examining the pattern of medication administration across all participants and were collapsed into the 5 most common patterns: (1) β-adrenergic agonist and/or theophylline only; (2) β-adrenergic agonist and cromolyn sodium with or without theophylline; (3) inhaled corticosteroids and β-adrenergic agonist with or without cromolyn, or inhaled corticosteroids and theophylline with or without cromolyn; (4) inhaled corticosteroid only or in combination with cromolyn, or cromolyn only; or (5) no medication. Children receiving inhaled corticosteroids and cromolyn were further classified into an inhaled anti-inflammatory group.

Bivariate analysis of NUs vs NNUs were examined using χ² analysis for the categorical variables (previous ED visits [ever] and hospitalized last 6 months [yes/no]) and t test for continuous variables (mean number of days and nights with symptoms, mean number of visits to regular physician for care). We additionally analyzed the NU group for differences in asthma morbidity measures and asthma management characteristics by administration of inhaled anti-inflammatory (receiving inhaled corticosteroids or cromolyn vs not receiving anti-inflammatory medications). All data analysis was conducted using SAS 7.0 (SAS Institute, Cary, NC).

Overall, children were primarily male (58%), African American (98.6%), and had a mean age of 8.2 years (age range, 5-12 years). Most respondents (89%) were either the child's biological mother or father. Most parents (75%) reported receiving at least a high school education or general education diploma. The number of household members was high with more than two thirds (68%) reporting 4 or more people living in the household. Although most mothers (79%) reported they did not have asthma, more than half (54%) reported other family members with asthma. More than half (60%) reported medical assistance as the child's type of medical insurance, and half (53%) reported receiving Aid to Families With Dependent Children (AFDC) or welfare.

Of 686 identified children with mild, persistent asthma or a greater severity of asthma, 231 (33%) reported using a nebulizer for medication administration at least 1 or more days per month. Three hundred twelve (45%) reported having a nebulizer machine at home. Nebulizer users were significantly younger (P = .02) and more likely to be male (P = .05) compared with NNUs (P = .02) (Table 1). A logistic regression model indicated that age and sex were independently associated with nebulizer use (children aged 2-6 years, odds ratio [OR] = 2.4, P = .003; aged 7-8 years, OR = 2.0, P = .01; aged 9-10 years, OR = 1.5, P = .13) (reference groups, aged ≥11 years, male, OR = 1.4, P = .03). Although there was a statistically significant difference by ethnicity, there was very little variation by ethnicity in the total sample.

Nebulizer use was significantly more frequent in children younger than age 8 years (Table 1) (P = .02). Among NUs, though there was no significant difference between the mean number of times using a nebulizer in the past 30 days by age (F₃ = 0.90, P = .44), children younger than age 11 years tended to report a higher mean number of times of use (aged 6 years, 25.4 times; aged 7-8 years, 23.8 times; aged 9-10 years, 24.6 times; and aged ≥11 years, 13.6 times).

As given in Table 2, the NU group had significantly more lifetime hospital admissions (P = .001), a higher rate of hospitalizations during the past 6 months (P = .001), a higher mean number of days and nights with symptoms (P = .001), more children with at least 11 school absences in the past year (P = .001), a higher proportion of 3 or more ED visits in the last 6 months (P = .001), and a higher proportion of children with a previous ED visit compared with the NNU group (P = .001). Additionally, NUs had a higher rate of oral steroid administration in mean number of times receiving oral steroids in the last 12 months (P = .003) and a higher percentage of children reporting oral steroid administration in the last 30 days (P = .001) compared with NNUs.

Administration of a β-adrenergic agonist medication alone or in combination with theophylline was the predominant type of asthma medication for both groups (51%, NNUs; 46%, NUs) (Table 3). The NUs had a higher percentage of cromolyn administration in combination with a β-adrenergic agonist with and without theophylline compared with the NNUs (NNUs, 9%; NUs, 33%). Theophylline administration was low for both groups (NNUs, 10 [2%] of 455; NUs, 9 [4%] of 231). Inhaled corticosteroid administration only or in combination with a bronchodilator was low for both groups (NNUs, 36 [8%] of 455; NUs, 35 [15%] of 231), and there was a significant difference between the 2 groups (χ²₁ = 7.89, P = .004). No medication was received by almost one third (32%) of the NNUs. Data for type of medication administered were missing for 6% of NUs.

Children receiving inhaled anti-inflammatory medications, defined as any cromolyn or inhaled corticosteroid, had increased morbidity as evidenced by a significantly increased rate of a hospitalization in the past 6 months (P = .004), increased number of days and nights with symptoms (P = .03), more children with 3 or more ED visits in the last 6 months (P = .05), and an increased mean number of nebulizer treatments in the last 30 days (group not receiving inhaled anti-inflammatory medications, 16 times; group receiving inhaled anti-inflammatory medications, 32 times; P = .03) (Table 4). Administration of oral steroids in the past 12 months was reported significantly more often by those receiving inhaled anti-inflammatory medications (P<.001). There were no significant differences in the number of school days missed by administration of inhaled anti-inflammatory medications.

As given in Table 5, children receiving inhaled anti-inflammatory medications reported significantly more physician visits for regular asthma care in the past 12 months (P = .03) and had a peak flow meter in the home (P = .001) compared with children receiving noninhaled anti-inflammatory medications. Although not statistically significant, there was a trend for the children receiving anti-inflammatory medications to have undergone allergy testing (P = .08). The 2 groups did not differ by having a regular source of asthma care; more than 97% of children in both groups reported having a regular source of asthma care. Last, there were no differences in sociodemographic status by administration of inhaled anti-inflammatory medications (income, P = .60; receiving medical assistance, P = .26; receiving AFDC, P = .29; or caregiver unable to afford asthma medicines or physician visits, P = .79).

These data confirm that nebulizer use is high in inner-city children with asthma (33%), consistent with a recent prevalence rate for nebulizer use for patients with asthma of all ages (32%).²² In our study, one third of children older than age 6 years reported nebulizer use at least 1 day per month. Although nebulizer use was significantly more frequent in children younger than age 8 years, 40% of NUs were aged 8 years or older. This high rate of nebulizer use in older children is concerning. The NAEPP guidelines suggest nebulizer use for children aged 2 years or younger or when a proper MDI with spacer technique cannot be achieved.¹⁷ Considerable research supports that MDIs with spacers and nebulizers are equally efficient in administering inhaled medications to children with asthma,^{9 ,11 - 14 ,23 - 27} suggesting that the preferred mode of asthma medication delivery for children is use of an MDI with a spacer. Cost-savings of MDI use vs nebulizer use were reported to be 4-fold in reducing billing charges for acutely ill, hospitalized patients with acute exacerbation of obstructive airway disease.²⁴ In children, similar reductions of nebulizer use and increase of MDI use should yield comparable cost-savings. However, owing to some regulatory issues, medical assistance insurance may not cover the cost of a spacer for MDI use, resulting in less effort and out-of-pocket expense for some caregivers to obtain a nebulizer.

Even though an MDI with a spacer is the preferred mode of delivery of inhaled medications,²⁸ many physicians continue to prescribe nebulizers for home use.²⁹ Ideally, the decision to prescribe an MDI or nebulizer is based on family needs and the child's inhalation and coordination skill level.³⁰ Physicians who treat inner-city children with asthma may believe that nebulizer use improves morbidity in this group of children, particularly if parents are more prone to use a nebulizer than an MDI for acute asthma episodes. Anecdotally, many families reported requesting a nebulizer for their child to avoid an ED visit by having the "same machine as they use in the emergency room." Additionally, families reported "sharing" a nebulizer among family members and neighbors. While we lack objective data to support these claims, it is troubling to consider that a nebulizer may be misused or may lead to delay in seeking medical care for a child experiencing an acute exacerbation of asthma.

We observed a high rate of morbidity in this population, including increased hospitalizations, ED visits, days and nights with symptoms, and school absences, suggesting a more severe asthma that requires long-term, inhaled corticosteroid therapy.¹⁷ Despite the high prevalence of nebulizer use in this sample, an extraordinarily low rate of children (15%) reported receiving inhaled corticosteroids. While this is contrary to NAEPP guidelines,¹⁷ it is consistent with previous reports of low rates of inhaled corticosteroid administration in inner-city pediatric populations.³¹ This lack of inhaled corticosteroid therapy may be a major contribution to poor asthma control²¹ as evidenced in this sample. Our data indicate serious undertreatment of an identified high-risk group of children with asthma whose morbidity was significantly increased compared with NNU counterparts.

On the other hand, use of anti-inflammatory medication in the NU group was not associated with a decrease in asthma morbidity as evidenced by the increased number of ED visits, administration of oral steroids, and days and nights with symptoms in those receiving inhaled anti-inflammatory medications vs those not receiving them. Perhaps this reflects a subgroup of NUs who receive anti-inflammatory medications but whose symptoms are more severe and require more ED visits for control of asthma. An alternative hypothesis may be confounding by severity^{32 - 34} in which anti-inflammatory medications are more likely to be prescribed to children who have more severe asthma, which is associated with a higher probability of an ED visit or hospitalization. Sociodemographic factors such as income, receiving medical assistance, or receiving AFDC did not influence the administration of inhaled anti-inflammatory medication. Thus, there was no disparity of inhaled anti-inflammatory administration in the more disadvantaged families. It is unclear if this low rate of inhaled anti-inflammatory administration is a result of physicians not following clinical practice guidelines due to lack of awareness, familiarity, agreement, or outcome expectancy³⁵ or families' failure to fill or adhere to prescribed medications.^{36 - 40} Considerable failure to refill medication was shown in a pediatric asthma study in which 63% of caregivers reportedly were out of albuterol for their child when the child was seen in the ED and the caregiver indicated that 1 of their child's medications was albuterol.³⁸ In either case, low rates of administration of inhaled corticosteroid medication is of great concern based on the high morbidity we observed and indicates the need for increased attention to both provider and patient education regarding preventive therapy. There is some evidence that this subgroup of children receiving inhaled corticosteroids demonstrated a pattern of receiving more NAEPP guideline–based care (eg, more physician visits for regular asthma care, more likely to have a peak flow meter, and a trend toward receiving allergy tests, a marker for specialty care).

This study's findings must be interpreted with some caution. This study relied on a structured interview rather than clinical records, so it is likely that parental reports of asthma morbidity are subject to recall bias. Furthermore, all surveyed families had consented to participating in a school- or home-based asthma education program. Therefore, this sample might be biased toward families that are either more concerned about their child's asthma or more in need of asthma education and services. However, the asthma morbidity and health care utilization baseline data found in this intervention study are remarkably similar to other inner-city asthma surveys that did not enroll participants in an asthma intervention.^{41 - 42} For this reason, we believe that our participants are representative of urban African American families with a child with asthma. Another caveat with our self-reported data is that we are unable to determine if a nebulizer or medication was not prescribed or whether there was poor adherence with a prescribed treatment plan. Verification of type of medications and presence of a peak flow meter in the home was not conducted owing to budgetary restraints. However, families were asked to obtain all of their child's medications at the beginning of the interview so that the parent could read the label for medication name and instructions for use. We feel that we report actual practice in the home, which reflects the reality of the child's asthma care.

In conclusion, we observed high nebulizer use in inner-city children despite the limited evidence base for nebulizer use in children older than age 2 years. We also observed that this group of high-risk children was undertreated (6 of 7 children) with inhaled corticosteroids for long-term control of their asthma. We recommend that nebulizer therapy should not be used in the absence of an NAEPP guideline–based preventive medication regimen. Further studies need to carefully evaluate the clinical benefit and cost-effectiveness of home-based nebulizer therapy on asthma morbidity in inner-city children.

Accepted for publication May 30, 2000.

This research was supported by the National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Md, grants R18-HL52013 and HL52833 (Dr Rand).

The authors thank Barbara Calabrese, RN, Francine Lampros-Klein, MEd, and David Lang, MD, for their thoughtful review of the manuscript.

Reprints: Arlene M. Butz, ScD, RN, Department of Pediatrics, Johns Hopkins University, School of Medicine, 600 N Wolfe St, Baltimore, MD 21287-3144 (e-mail: Abutz@jhmi.jhu.edu).