Adding oscillometry to spirometry in guidelines better identifies uncontrolled asthma, future exacerbations, and potential targeted therapy.

The objective of this review is to provide new advances in our understanding of the clinical importance of establishing peripheral airway impairment (PAI) by impulse oscillometry (IOS) and targeted therapy, which could result in better asthma outcomes. Data sources include PubMed and Google search, limited to English language and human disease, with key words IOS and asthma. Key findings include PAI being consistently associated with uncontrolled asthma across ethnicities, using IOS reference equations factoring Hispanic and White reference algorithms. It is noted that PAI is common even in patients considered well-controlled by asthma guidelines. In a large longitudinal analysis (Assessment of Small Airways Involved in Asthma or ATLANTIS study), a composite of R5-R20, AX, and X5 ordinal scores were independently predictive of asthma control and exacerbation in a multivariate analysis, but forced expiratory volume in 1 second was not significantly predictive of morbidities. However, combining forced expiratory volume in 1 second less than 80% with PAI resulted in greater odds of identifying uncontrolled asthma and exacerbations, than either alone. Applying an external validation method in children with asthma offers the clinician the IOS reference equations best fit for their own specific population. Several clinical phenotypes can also identify PAI with high probability, useful when IOS is not available. Poor asthma outcomes for obese patients with asthma are associated with dysanapsis and PAI, not obesity alone. Extrafine inhaled corticosteroids achieve better asthma control and improve peripheral airway function with fewer exacerbations at lower dosages than nonextrafine inhaled corticosteroid aerosols. In conclusion, these data support the benefit of adding IOS to spirometry in future asthma guidelines and suggest the potential benefit from targeted therapy.

In young children with asthma, obesity and uncontrolled disease are highly associated with peripheral airway impairment.

BACKGROUND: Despite the fact that impulse oscillometry (IOS)-determined peripheral airway impairment (PAI) phenotype is a major risk factor for uncontrolled asthma, IOS is seldom used clinically. OBJECTIVE: To identify clinical characteristics that can best identify the PAI phenotype. METHODS: Clinical characteristics and spirometry results were compared in 227 patients with asthma with the PAI phenotype determined by resistance and reactance values that exceeded IOS­predictive normal values using Gochicoa-Rangel equations. Logistic regression analyses determined factors associated with PAI phenotype, with risk classification based on predicted probability from the final adjusted model. RESULTS: Analysis for identifying PAI, present in 37% of our population, revealed statistically significant odds ratio (OR) for age (4-7 years), of 3.75 (1.47-9.55) (P = .006), obesity OR of 2.59 (1.36-4.96) (P = .004), uncontrolled asthma OR of 2.77 (1.34-5.74) (P = .006), and abnormal forced expiratory flow between 25% and 75% (FEF25%-75%) (<65%) OR of 4.22 (1.59-11.20) (P = .004). For identifying PAI in those considered well controlled, key characteristics were age (4-7 years), OR of 2.81 (1.10-7.18) (P = .03), and obesity, OR of 2.18 (1.09-4.39) (P = .03). For those 4 to 7 years old, who were obese and had uncontrolled disease, probability of PAI was greater than or equal to 80%, regardless of FEF 25%-75%. Probabilities from logistic regression analyses to identify PAI were associated with an area under the curve of 0.750, and applying standard threshold of greater than or equal to 0.50 probability for identification produced sensitivity at 49.4%, specificity at 85.3%, positive predictive value at 66.1%, negative predictive value at 74.4%, and accuracy at 72.1%. CONCLUSION: Clinical characteristics of age at 4 to 7 years, obesity, uncontrolled asthma, and FEF 25%-75% (<65%) identify PAI with high specificity and accuracy. This approach offers the clinician a practical method for strongly considering the presence of PAI when IOS is not available.

Evaluating the impact of coronavirus disease 2019 on asthma morbidity: A comprehensive analysis of potential influencing factors.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic period is experiencing better asthma control, fewer exacerbations, and health care utilization, with limited data on factors that could explain this phenomenon. OBJECTIVE: To confirm these improved asthma outcomes during COVID-19 and evaluate potential contributing factors. METHODS: In 18,912 pediatric patients with asthma treated in the Children's Hospital of Orange County network from 2017 to 2020, monthly asthma-related encounters and medication summaries were extracted from electronic health records, particulate matter 2.5 (PM2.5) air pollution from the California Air Resources Board, and influenza-like illness from Illness Surveillance Network for the first 6 months of each year. Changes in outcomes between January to March and April to June (post-COVID-19 shutdown in 2020) were compared with historical data using generalized estimating equations analyses for patient outcomes and generalized linear models for pollution exceedance, influenza-positive, and telehealth visit rates. RESULTS: During COVID-19, we found 78%, 90%, 68% reductions in hospitalization, emergency department visits, and exacerbations, respectively, compared with pre-COVID-19 2020, with significantly greater changes than the same time period of 2017 to 2019 and significant reductions in albuterol and inhaled corticosteroid use (P < .05). Emergency department visit reduction was not seen for African Americans. The PM2.5 and influenza rates were also significantly reduced during COVID-19 (P < .05). Increased rates in telehealth visits were greater in the publicly insured group when compared with commercially insured. CONCLUSION: Our data confirm reduced health care utilization and suggest better asthma control during COVID-19, except for African Americans. This was associated with a significant increase in telehealth visits and reductions in PM2.5 and influenza infections, but not better asthma controller adherence.

The impact of caregiver health literacy on healthcare outcomes for low income minority children with asthma.

Objectives: The aim of this exploratory study was to assess the impact of caregiver health literacy (HL) on health care outcomes for their child with asthma.Methods: Caregiver dyads across two different healthcare delivery systems completed a battery of validated asthma outcome instruments, including the Newest Vital Sign™ as a measure of HL for the caregivers of children ages 7-18 y. Utilization history was obtained through the electronic medical record. Descriptive analysis with bivariate associations was conducted.Results: There was no direct relationship between HL and asthma outcomes in the 34 Hispanic and African American caregiver-child dyads. However, caregiver health literacy was significantly related to language (p = 0.02). African American English-speaking caregivers, seen in an urban emergency department, demonstrated adequate health literacy. Hispanic Spanish-speaking caregivers, seeking care in a mobile asthma van, showed limited health literacy. There was no significant association between caregivers' HL and routine asthma care visits when language and child age were controlled.Conclusions: Assessing patient factors can identify persons at risk who need additional support to negotiate the healthcare system when providing care for a child with asthma.

Can asthma be well controlled with NAEPP guideline care in morbidly obese children? The Breathmobile.

BACKGROUND: Obesity is thought to be associated with poor asthma control, increased health resource utilization, and reduced responsiveness to inhaled corticosteroids. OBJECTIVE: Based on previous experience, our hypothesis was that by improved access to comprehensive guideline care, outcomes in normal weight would be comparable in obese children with asthma. METHODS: This was a retrospective cohort study of predominately Hispanic children (3-18 years of age) in underserved areas of Orange County, California, who enrolled in the Breathmobile Program from 2003 to 2012. Outcomes were examined by using Cox regression and generalized estimating equations analyses, adjusted for potential confounding factors. RESULTS: Clinical outcomes in more than 1,200 children followed up for a mean of 6 visits (standard deviation [SD] = 2.2) across 403 days (SD = 112) were improved, on average, regardless of body mass index (BMI). Morbidly obese (MOB) patients were able to achieve significant reductions of approximately 60% or more in report of emergency department (ED) visits, hospitalizations, school absenteeism, usual exercise limitations, and exacerbations to levels that were comparable those of normal weight (NW) patients. The importance of close follow-up, particularly for the MOB patient, was evidenced by achieving 80% cumulative probability of well controlled asthma by visit 3, similar to patients in lower BMI risk groups with good adherence, when the visit interval did not exceed 90 days. These outcomes were achieved across all BMI groups with similar mean step of therapy, adjusted for severity (P < .001). CONCLUSION: Access to effective community-based care where trust, education, and continuity of care consistent with National Asthma Education and Prevention Program (NAEPP) guidelines is possible, as demonstrated by the Breathmobile Program, can provide an opportunity for children with asthma in all BMI categories to achieve well-controlled disease.

Phenotypes favoring fractional exhaled nitric oxide discordance vs guideline-based uncontrolled asthma.

BACKGROUND: Despite potential value of identification of allergic inflammation with fractional exhaled nitric oxide (FeNO) in managing asthma, randomized clinical trials have not consistently shown better outcomes compared with guideline management alone. OBJECTIVE: To assess the effectiveness of FeNO vs non-FeNO-based therapeutic algorithms in managing asthma, and the phenotypic profile associated with FeNO >35 ppb yet well controlled by guidelines, as a potential model to predict better FeNO-based algorithm outcomes. METHODS: This is a randomized controlled study (RCT) in 88 high-risk children with asthma 7 to 18 years of age across 352 visits over a 1-year period. Generalized estimating equations analysis assessed algorithm group differences in outcomes and characteristics associated with higher odds uncontrolled by FeNO alone in the treatment decision algorithm. RESULTS: The FeNO treatment algorithm did not show superiority in reducing exacerbations and morbidity (P > .05). Phenotypes that more than doubled the odds FeNO alone identified uncontrolled asthma included adolescence, non-adherence, high atopy (>6+), and baseline FeNO >35 ppb, whereas obesity, FEF25-75% < 65% predicted, and bronchodilator response >10% decreased the odds. Uncontrolled asthma by FeNO alone (F) vs guidelines alone (G) showed overall F/G > 1.0 in adolescents, but <1.0 in younger patients unless the FeNO threshold was reduced to >20 ppb. CONCLUSION: Our study suggests that age and phenotypes play a key role in FeNO discordance compared with the conventional guideline-based uncontrolled asthma. The FeNO-based therapeutic algorithm, if confirmed further, could provide the clinician with an effective asthma management tool. The clinical implication could improve future FeNO-based RCTs and treatment decision algorithms in managing asthma by considering phenotypes and age-dependent FeNO thresholds.

Recognition of the peripheral airway impairment phenotype in children with well-controlled asthma.

BACKGROUND: Peripheral airway impairment, although frequently unrecognized, is a risk factor for poor asthma control, loss of control, increased exacerbations, airway hyperresponsiveness, and loss of lung function with age, even in patients with well-controlled asthma. OBJECTIVE: To determine the presence of peripheral airway impairment by impulse oscillometry and forced expiratory flow between 25% and 75% (FEF25%-75%) in children whose asthma is well controlled by National Asthma Education and Prevention Program (NAEPP) guidelines. METHODS: In this retrospective, cross-sectional analysis, outcomes were evaluated across 192 encounters in 139 patients with moderate to severe asthma, ages 4-18 years. Receiver operator characteristic curves were created and oscillometry thresholds determined by maximizing the sum of sensitivity and specificity to identify those whose condition is not well controlled. Impairment was then identified for those whose condition was well controlled when these age-dependent oscillometry thresholds were met for each IOS measure or FEF25%-75% < 65% of predicted. RESULTS: Reactance at 5 Hz (X5) appeared most robust to identify peripheral airway impairment. In 96 well-controlled asthma encounters, impairment was identified by X5 in approximately 20% and 45% for those younger than 12 years and adolescents, respectively, compared with a maximum of 10% with FEF25%-75% in the adolescent cohort (P < .05). CONCLUSION: We conclude that peripheral airway impairment, determined by oscillometry, is common in patients with well-controlled asthma across age cohorts. X5 with optimal cut points ≤ -3.8, ≤ -2.5, and ≤ -1.5 cmH2O/L/s for ages 4-7, 8-11, and >12 years, provides the clinician with a practical tool to identify the presence of the peripheral airway impairment phenotype that is consistently superior to FEF25%-75%. This recognition, if confirmed, may reduce the risk of asthma-associated consequences with earlier and more targeted therapy.

The case for impulse oscillometry in the management of asthma in children and adults.

OBJECTIVE: To provide a clinical rationale for including impulse oscillometry (IOS) as a part of standard office-based asthma assessment. DATA SOURCES: PubMed and Google search, limited to English language and human disease, with the keywords IOS and asthma. STUDY SELECTIONS: Articles included in this review were based on the expert opinion and previous publications by the authors. RESULTS: In children, IOS was more useful than spirometry in identifying asthma and uncontrolled asthma and predicting loss of control and exacerbations. IOS predicts young children at risk for loss of lung function with age and the potential for early intervention to prevent further sequelae. In adults, peripheral airway impairment detected by IOS or spirometry (ie, forced expiratory flow between 25% and 75%) commonly occurs across severity, and each measure may be complementary in predicting loss of control even with normal forced expiratory volume in 1 second. Extrafine inhaled corticosteroids with or without long-acting ß-agonists proved superior to standard particle aerosols in improving IOS-detected peripheral airway obstruction. Our data also suggest that currently available commercial reference values for lung resistance at 5 Hz and lung reactance at 5 Hz are applicable across diverse populations, but further studies are needed. CONCLUSION: The findings of this review suggest that IOS can add value to traditional clinical and spirometric assessment and thus improve management of asthma in children and adults, as well as have the potential to detect early dysfunction of the peripheral airways, which may result in better outcomes.

Obesity, Asthma, and Exercise in Child and Adolescent Health.

Obesity increases the risk of asthma throughout life but the underlying mechanisms linking these all too common threats to child health are poorly understood. Acute bouts of exercise, aerobic fitness, and levels of physical activity clearly play a role in the pathogenesis and/or management of both childhood obesity and asthma. Moreover, both obesity and physical inactivity are associated with asthma symptomatology and response to therapy (a particularly challenging feature of obesity-related asthma). In this article, we review current understandings of the link between physical activity, aerobic fitness and the asthma-obesity link in children and adolescents (e.g., the impact of chronic low-grade inflammation, lung mechanics, and direct effects of metabolic health on the lung). Gaps in our knowledge regarding the physiological mechanisms linking asthma, obesity and exercise are often compounded by imprecise estimations of adiposity and challenges of assessing aerobic fitness in children. Addressing these gaps could lead to practical interventions and clinical approaches that could mitigate the profound health care crisis of the increasing comorbidity of asthma, physical inactivity, and obesity in children.

Effectiveness of a promotora home visitation program for underserved Hispanic children with asthma.

OBJECTIVE: Retention in a mobile asthma clinic, the Breathmobile™, of ≥3 visits has previously been shown to be essential for attaining asthma control in underserved children. The objective of this study in primarily Hispanic-American children was to determine the difference in retention between those seen in the Breathmobile™ compared to those receiving an additional promotora-based home visit (HV). METHODS: Children with asthma in the Breathmobile™ program were evaluated for asthma status and aeroallergen sensitivity. Indication for HV included poor asthma control, educational and environmental control needs. An initial visit consisted of environmental assessment as well as a 3-h interactive educational session covering asthma basics. A follow-up visit 1 month later assessed implementation. The primary outcome measure of retention was ≥6 months in the Breathmobile™ program. RESULTS: Of the 1007 asthmatic children seen between April 2002 and June of 2005, 136 received HV. These children showed significantly greater retention compared to those without HV with a median number of visits (5 visits versus 2 visits), ≥3 Breathmobile™ visits (86.0% versus 38.8%), median number of days in the program (299 versus 63 days) and percentage of patients in the program ≥6 months (67.8% versus 31.3%) p < 0.001. HV and asthma severity were each independent predictors of retention. CONCLUSIONS: The addition of a promotora HV program proved effective in providing greater retention in the Breathmobile™ program essential for asthma control. Randomized clinical trials will be needed to show the impact on health care utilization and asthma control.

The prevalence of asthma risk and contributing factors in underserved Vietnamese children in Orange County, CA.

OBJECTIVES: Vietnamese constitutes one of the fastest growing minority groups in America, with the largest concentration in Orange County (OC), CA. Yet, there are limited data on the prevalence of asthma in Vietnamese children. Our study evaluated the risk of asthma and key contributing factors among these children living in OC, CA. METHOD: Five elementary schools in OC that were predominantly Vietnamese with low socioeconomic status were selected for participation. Validated surveys were sent to parents of all students ages 3-12 in these schools with materials available in English, Vietnamese and Spanish. Surveys included questions to identify the risk of asthma and related key factors. Surveys were completed by parents and returned to schools. RESULTS: There were 1530 participants eligible for analysis. Asthma risk was 30.4%, and of these, 22.6% had no prior diagnosis. Contributing factors to identification of those at risk were male gender (p < 0.001), preferred use of the Vietnamese language (p = 0.004), longer duration in the United States (p = 0.019), and smoker in the household (p = 0.015). CONCLUSIONS: The prevalence of asthma risk in our community of low socioeconomic status Vietnamese children was found to be higher than commonly appreciated. Furthermore, a considerable number of these children had not been previously diagnosed. Given the limited information in this population, our current findings of asthma risk and key contributing factors could affect health care policies that allow appropriate funding for programs dedicated to asthma care in this and other growing population.

Peripheral airway impairment measured by oscillometry predicts loss of asthma control in children.

BACKGROUND: We previously showed that impulse oscillometry (IOS) indices of peripheral airway function are associated with asthma control in children. However, little data exist on whether dysfunction in the peripheral airways can predict loss of asthma control. OBJECTIVE: We sought to determine the utility of peripheral airway impairment, as measured by IOS, in predicting loss of asthma control in children. METHODS: Fifty-four children (age, 7-17 years) with controlled asthma were enrolled in the study. Spirometric and IOS indices of airway function were obtained at baseline and at a follow-up visit 8 to 12 weeks later. Physicians who were blinded to the IOS measurements assessed asthma control (National Asthma Education and Prevention Program guidelines) on both visits and prescribed no medication change between visits. RESULTS: Thirty-eight (70%) patients maintained asthma control between 2 visits (group C-C), and 16 patients had asthma that became uncontrolled on the follow-up visit (group C-UC). There was no difference in baseline spirometric results between the C-C and C-UC groups, except for FEV1/forced vital capacity ratio (86% vs 82%, respectively; P < .01). Baseline IOS results, including resistance of the respiratory system at 5 Hz (R5; 6.4 vs 4.3 cm H2O · L(-1) · s), frequency dependence of resistance (difference of R5 and resistance of the respiratory system at 20 Hz [R5-20]; 2.0 vs 0.7 cm H2O · L(-1) · s), and reactance area (13.1 vs 4.1 cm H2O · L(-1)), of group C-UC were significantly higher than those of group C-C (P < .01). Receiver operating characteristic analysis showed baseline R5-20 and reactance area effectively predicted asthma control status at the follow-up visit (area under the curve, 0.91 and 0.90). CONCLUSION: Children with controlled asthma who have increased peripheral airway IOS indices are at risk of losing asthma control.

Relating small airways to asthma control by using impulse oscillometry in children.

BACKGROUND: Previous reports suggest that the peripheral airways are associated with asthma control. Patient history, although subjective, is used largely to assess asthma control in children because spirometric results are many times normal values. Impulse oscillometry (IOS) is an objective and noninvasive measurement of lung function that has the potential to examine independently both small- and large-airway obstruction. OBJECTIVE: We sought to determine the utility of IOS in assessing asthma control in children. METHODS: Asthmatic and healthy children (6-17 years) were enrolled in the study. Spirometric and IOS (resistance of the respiratory system at 5 Hz [R5] and 20 Hz [R20], reactance of the respiratory system at 5 Hz [X5], resonant frequency of reactance [Fres], and area under the reactance curve between 5 Hz and Fres [reactance area {AX}]) values were collected in triplicate before and after a bronchodilator was administered. The physicians were blinded to the IOS measurements and assessed asthma control using American Thoracic Society guidelines. RESULTS: Small-airway IOS measurements, including the difference of R5 and R20 [R5-20], X5, Fres, and AX, of children with uncontrolled asthma (n = 44) were significantly different from those of children with controlled asthma (n = 57) and healthy children (n = 14), especially before the administration of a bronchodilator. However, there was no difference in large-airway IOS values (R20). No differences were found between children with controlled asthma and healthy children in any of the end points. Receiver operating characteristic analysis showed cut points for baseline R5-20 (1.5 cm H(2)O · L(-1) · s) and AX (9.5 cm H(2)O · L(-1)) that effectively discriminated controlled versus uncontrolled asthma (area under the curve, 0.86 and 0.84) and correctly classified more than 80% of the population. CONCLUSION: Uncontrolled asthma is associated with small-airways dysfunction, and IOS might be a reliable and noninvasive method to assess asthma control in children.

School asthma screening and case management: attendance and learning outcomes.

Asthma is related to school absenteeism and underperformance in elementary students. This pilot study assessed whether school nurse case management (CM) in children identified with asthma impacts academic performance and school absenteeism in one school. A validated questionnaire was used to identify children at risk for asthma and CM was provided to link these students to medical care and assure asthma action plans at school. In the 40 children with confirmed diagnosis who received CM, academic performance on standardized testing postintervention was similar to the 76 children who were low risk for asthma. Average days absent due to illness in the CM group were reduced from 5.8 to 3.7 days in the postintervention school year. School nurse screening, CM, and collaboration with a medical provider resulted in early identification, referral, and subsequent treatment of students at risk for asthma and may have contributed to reduced illness absences.

External validation can provide the clinician with IOS equations that best predict the risk of uncontrolled asthma in their population.

BACKGROUND: Peripheral airway impairment (PAI) has been shown to have a close association to risk of uncontrolled asthma in children. However, clear methods have not been established for the clinician to select impulse oscillometry (IOS) reference equations best suited for their population. Our study aimed to develop a practical external validation analytic approach for the clinician to determine which of the available reference equations best predicts uncontrolled asthma for their patients. METHODS: This is a post hoc analyses of data collected at baseline in a randomized controlled study that occurred from March 2016 to 2018. The study population consisted of 227 children, ages 4-18 years, with moderate to severe asthma. Discrimination and calibration predictive performance of available and suitable IOS equations were assessed by using uncontrolled asthma as the criterion outcome. Discrimination statistics of accuracy, sensitivity, and specificity served as the primary performance indicators. Rank scores were determined by the number of acceptable limit thresholds met for these measures (≥60%, ≥50%, and ≥60%, respectively) across IOS metrics (R5, R5-R20, AX, and X5) resulting in a total possible score of 12. RESULTS: External validity assessment determined the rank order of best to worst equations as being Gochicoa-Rangel (rank score = 10) > Nowowiejska (rank score = 9) > Assumapcao (rank score = 6) > Amra (rank score = 2). Gochicoa-Rangel reference equations provided the best option for universal application with accuracy of 73.1%, 72.2%, 76.7%, and 66.2% for R5, R5-R20, AX, and X5, respectively. CONCLUSIONS: External validation, particularly discrimination in asthmatic children, offers the clinician a practical approach to selecting the most suitable predictive equations for their patients.

Cut points for Asthma Control Tests in Mexican children in Orange County, California.

BACKGROUND: The Childhood Asthma Control Test (C-ACT) and the Asthma Control Test (ACT) are validated measures of asthma control in which a score of 19 is defined as uncontrolled according to published reports. However, different cut points may exist in different ethnic populations. OBJECTIVE: To determine the cut point for uncontrolled asthma in a Mexican descent population from Orange Country, California, compared with an age- and asthma severity-matched non-Hispanic cohort. METHODS: The C-ACT (in children 6-11 years old) and ACT (in children 12-17 years old) scores were collected from 151 children of Mexican descent and 48 non-Hispanic controls with mild-to-moderate asthma who lived in Orange County. Physicians were masked to C-ACT and ACT scores while assessing control based on National Asthma Education and Prevention program guidelines. The receiver operating characteristic method was used to examine the screening accuracy of the tests to detect uncontrolled asthma. The optimal cut points were selected by maximizing the total sensitivity and specificity. RESULTS: Cronbach α values for the C-ACT (0.76) and the ACT (0.80) confirmed that both tests were reliable in our study population. The C-ACT and ACT scores were statistically higher in children of Mexican descent than non-Hispanic children (P = .008). A cut point of 22 was optimal to detect uncontrolled asthma in children of Mexican descent 6 to 11 years old (group 1: sensitivity, 0.74; specificity, 0.86; area under the curve [AUC], 0.83) and children 12 to 17 years old (group 3: sensitivity, 0.78; specificity, 0.68; AUC, 0.79). For non-Hispanic controls, a cut point of 20 were optimal to detect uncontrolled asthma in children 6 to 11 years old (group 2: sensitivity, 0.70; specificity, 0.91; AUC, 0.86) and children 12 to 17 years old (group 4: sensitivity, 0.83; specificity, 0.87; AUC, 0.91). CONCLUSION: In this cross-ethnic validation study, children of Mexican descent in Orange County seem to underreport asthma symptoms compared with a non-Hispanic population and may require higher C-ACT and ACT cut points to detect uncontrolled asthma.

Achieving and maintaining asthma control in inner-city children.

BACKGROUND: Despite guidelines-defined care, inner-city children of low socioeconomic status have poor asthma control. OBJECTIVE: This study evaluated time to achieve control, maintenance of control, and factors associated with well controlled asthma for pediatric patients receiving specialty-based asthma care in mobile asthma clinics designed to reduce barriers to delivering effective asthma care (the Breathmobile Program). METHODS: Existing clinical data collected from January 1998 to June 2008 for 7822 pediatric patients with asthma (34,339 visits) enrolled in similarly structured mobile asthma programs across the United States evaluated the effect of asthma control on the reduction of asthma-related morbidity, time to achieve asthma control, maintenance of asthma control, and factors associated with well controlled asthma. RESULTS: Comparison of pre and post year data for subjects enrolled in the program for at least 1 year revealed reductions in the percentage of patients reporting emergency department visits (mean, 66%), hospitalizations (mean, 84%), and missed school days ≥5/year (mean, 78%). Well controlled asthma was achieved by visit 3 for an estimated 80% of patients. Factors contributing to well controlled asthma include non-African American race, visit interval <90 days, and adherence to prescribed therapy. CONCLUSION: This study demonstrates the ability to achieve and maintain asthma control in high-risk populations in association with intensive, accessible, guidelines-defined care with close follow-up.