Bedroom allergen exposures in US households.

BACKGROUND: Bedroom allergen exposures contribute to allergic disease morbidity because people spend considerable time in bedrooms, where they come into close contact with allergen reservoirs. OBJECTIVE: We investigated participant and housing characteristics, including sociodemographic, regional, and climatic factors, associated with bedroom allergen exposures in a nationally representative sample of the US population. METHODS: Data were obtained from National Health and Nutrition Examination Survey 2005-2006. Information on participant and housing characteristics was collected by using questionnaires and environmental assessments. Concentrations of 8 indoor allergens (Alt a 1, Bla g 1, Can f 1, Fel d 1, Der f 1, Der p 1, Mus m 1, and Rat n 1) in dust vacuumed from nearly 7000 bedrooms were measured by using immunoassays. Exposure levels were classified as increased based on percentile (75th/90th) cutoffs. We estimated the burden of exposure to multiple allergens and used multivariable logistic regression to identify independent predictors for each allergen and household allergen burden. RESULTS: Almost all participants (>99%) had at least 1 and 74.2% had 3 to 6 allergens detected. More than two thirds of participants (72.9%) had at least 1 allergen and 18.2% had 3 or more allergens exceeding increased levels. Although exposure variability showed significant racial/ethnic and regional differences, high exposure burden to multiple allergens was most consistently associated with the presence of pets and pests, living in mobile homes/trailers and older and rental homes, and living in nonmetropolitan areas. CONCLUSIONS: Exposure to multiple allergens is common. Despite highly variable exposures, bedroom allergen burden is strongly associated with the presence of pets and pests.

Sensitization and Exposure to Pets: The Effect on Asthma Morbidity in the US Population.

BACKGROUND: Although pets are found in more than 50% of US homes, the effect of pet allergen exposure on asthma morbidity in the US population is not well documented. OBJECTIVE: To determine the effect of dog and cat allergen exposures on asthma morbidity in the US population. METHODS: The National Health and Nutrition Examination Survey is a representative sample of civilian US population. Data on asthma, dog and cat allergen levels in bedroom dust, as well as specific IgE to dog and cat were analyzed for all participants 6 years or older. RESULTS: Pets are common in the United States, with more that 50% of households having a dog or a cat or both. The prevalence of allergic sensitization in the National Health and Nutrition Examination Survey population was similar for dog and cat, with both being approximately 12%. Among those who were sensitized, exposure to elevated levels of pet allergens was associated with an increased prevalence of asthma and asthma attacks. Indeed, 44.2% of the asthma attacks were attributable to exposure to high levels of dog allergen in the bedroom among patients with asthma sensitive to dog and 30.3% were attributable to cat allergen exposure among the comparable cat-sensitive and exposed group. Projecting these results to the US population indicates more than 1 million increased asthma attacks each year for the dog-sensitive and exposed group and more than 500,000 increased asthma attacks for the cat-sensitive and exposed population of patients with asthma. CONCLUSIONS: Exposure to elevated levels of dog and cat allergens among those sensitized individuals with asthma is associated with excess asthma attacks. Reducing pet allergen exposures has the potential for a significant decrease in asthma morbidity.

Can we predict fall asthma exacerbations? Validation of the seasonal asthma exacerbation index.

BACKGROUND: A Seasonal Asthma Exacerbation Predictive Index (saEPI) was previously reported based on 2 prior National Institute of Allergy and Infectious Diseases Inner City Asthma Consortium trials. OBJECTIVE: This study sought to validate the saEPI in a separate trial designed to prevent fall exacerbations with omalizumab therapy. METHODS: The saEPI and its components were analyzed to characterize those who had an asthma exacerbation during the Preventative Omalizumab or Step-Up Therapy for Fall Exacerbations (PROSE) study. We characterized those inner-city children with and without asthma exacerbations in the fall period treated with guidelines-based therapy (GBT) in the absence and presence of omalizumab. RESULTS: A higher saEPI was associated with an exacerbation in both the GBT alone (P < .001; area under the curve, 0.76) and the GBT + omalizumab group (P < .01; area under the curve, 0.65). In the GBT group, younger age at recruitment, higher total IgE, higher blood eosinophil percentage and number, and higher treatment step were associated with those who had an exacerbation compared with those who did not. In the GBT + omalizumab group, younger age at recruitment, increased eosinophil number, recent exacerbation, and higher treatment step were also associated with those who had an exacerbation. The saEPI was associated with a high negative predictive value in both groups. CONCLUSIONS: An exacerbation in children treated with GBT with or without omalizumab was associated with a higher saEPI along with higher markers of allergic inflammation, treatment step, and a recent exacerbation. Those that exacerbated on omalizumab had similar features with the exception of some markers of allergic sensitization, indicating a need to develop better markers to predict poor response to omalizumab therapy and alternative treatment strategies for children with these risk factors. The saEPI was able to reliably predict those children unlikely to have an asthma exacerbation in both groups.

Seasonal risk factors for asthma exacerbations among inner-city children.

BACKGROUND: Asthma exacerbations remain common, even in children and adolescents, despite optimal medical management. Identification of host risk factors for exacerbations is incomplete, particularly for seasonal episodes. OBJECTIVE: We sought to define host risk factors for asthma exacerbations unique to their season of occurrence. METHODS: This is a retrospective analysis of patients aged 6 to 20 years who comprised the control groups of the Asthma Control Evaluation study and the Inner City Anti-IgE Therapy for Asthma study. Univariate and multivariate models were constructed to determine whether patients' demographic and historical factors, allergic sensitization, fraction of exhaled nitric oxide values, spirometric measurements, asthma control, and treatment requirements were associated with seasonal exacerbations. RESULTS: The analysis included 400 patients (54.5% male; 59.0% African American; median age, 13 years). Exacerbations occurred in 37.5% of participants over the periods of observation and were most common in the fall (28.8% of participants). In univariate analysis impaired pulmonary function was significantly associated with greater odds of exacerbations for all seasons, as was an exacerbation in the previous season for all seasons except spring. In multivariate analysis exacerbation in the previous season was the strongest predictor in fall and winter, whereas a higher requirement for inhaled corticosteroids was the strongest predictor in spring and summer. The multivariate models had the best predictive power for fall exacerbations (30.5% variance attributed). CONCLUSIONS: Among a large cohort of inner-city children with asthma, patients' risk factors for exacerbation vary by season. Thus information on individual patients might be beneficial in strategies to prevent these seasonal events.

Prevalence of allergic sensitization in the United States: results from the National Health and Nutrition Examination Survey (NHANES) 2005-2006.

BACKGROUND: Allergic sensitization is an important risk factor for the development of atopic disease. The National Health and Nutrition Examination Survey (NHANES) 2005-2006 provides the most comprehensive information on IgE-mediated sensitization in the general US population. OBJECTIVE: We investigated clustering, sociodemographic, and regional patterns of allergic sensitization and examined risk factors associated with IgE-mediated sensitization. METHODS: Data for this cross-sectional analysis were obtained from NHANES 2005-2006. Participants aged 1 year or older (n = 9440) were tested for serum specific IgEs (sIgEs) to inhalant and food allergens; participants 6 years or older were tested for 19 sIgEs, and children aged 1 to 5 years were tested for 9 sIgEs. Serum samples were analyzed by using the ImmunoCAP System. Information on demographics and participants' characteristics was collected by means of questionnaire. RESULTS: Of the study population aged 6 years and older, 44.6% had detectable sIgEs, whereas 36.2% of children aged 1 to 5 years were sensitized to 1 or more allergens. Allergen-specific IgEs clustered into 7 groups that might have largely reflected biological cross-reactivity. Although sensitization to individual allergens and allergen types showed regional variation, the overall prevalence of sensitization did not differ across census regions, except in early childhood. In multivariate modeling young age, male sex, non-Hispanic black race/ethnicity, geographic location (census region), and reported pet avoidance measures were most consistently associated with IgE-mediated sensitization. CONCLUSIONS: The overall prevalence of allergic sensitization does not vary across US census regions, except in early life, although allergen-specific sensitization differs based on sociodemographic and regional factors. Biological cross-reactivity might be an important but not the sole contributor to the clustering of allergen-specific IgEs.

Lack of a relation between serum 25-hydroxyvitamin D concentrations and asthma in adolescents.

BACKGROUND: Decreased 25-hydroxyvitamin D [25(OH)D] concentrations have been associated with an increased prevalence and severity of asthma and a lower response to inhaled corticosteroids. OBJECTIVE: The objective was to determine the association between serum 25(OH)D concentrations and asthma prevalence, severity, and response to asthma treatment. DESIGN: Secondary analyses were conducted in 2 samples of adolescents 12-20 y of age: 1) NHANES 2001-2006 (n = 6487), a cross-sectional nationally representative sample of the US population, and 2) a cohort of inner-city adolescents with asthma managed prospectively for 46 wk with guidelines-based therapy in the Asthma Control Evaluation (ACE; n = 226) trial. RESULTS: Mean (±SD) serum 25(OH)D concentrations in the NHANES and ACE samples were lower in African Americans than in non-African Americans (NHANES: 14.9 ± 6.5 compared with 23.0 ± 8.4 ng/mL, P < 0.0001; ACE: 11.2 ± 6.9 compared with 15.8 ± 7.1 ng/mL, P < 0.0001). In the NHANES sample, mean concentrations did not differ between participants without and with asthma (African Americans: 14.9 ± 6.4 compared with 15.0 ± 6.6 ng/mL, respectively, P = 0.87; non-African Americans: 23.0 ± 8.5 compared with 23.6 ± 8.2 ng/mL, respectively, P = 0.16). In the ACE models that used either a predefined cutoff (<20 ng/mL) or linear regression, 25(OH)D concentrations showed either no relation or minor contradictory correlations with indicators of asthma severity, treatment requirements, spirometry, or atopy/inflammation. CONCLUSION: In 2 samples of adolescents, overall serum 25(OH)D concentrations were low and were not consistently associated with the presence of asthma, multiple asthma characteristics, asthma morbidity, or response to treatment. The ACE trial was registered at clinicaltrials.gov as NCT0011441.

A multi-center ring trial of allergen analysis using fluorescent multiplex array technology.

BACKGROUND: Consistent performance of allergen assays is essential to ensure reproducibility of exposure assessments for investigations of asthma and occupational allergic disease. This study evaluated intra- and inter-laboratory reproducibility of a fluorescent multiplex array, which simultaneously measures eight indoor allergens in a single reaction well. METHODS: A multi-center study was performed in nine laboratories in the US and Europe to determine the inter-laboratory variability of an 8-plex array for dust mite, cat, dog, rat, mouse and cockroach allergens. Aliquots of 151 dust extract samples were sent to participating centers and analyzed by each laboratory on three separate occasions. Agreement within and between laboratories was calculated by the concordance correlation coefficient (CCC). RESULTS: Results were obtained for over 32,000 individual allergen measurements. Levels covered a wide range for all allergens from below the lower limit of detection (LLOD = 0.1-9.8 ng/ml) to higher than 6800 ng/ml for all allergens except Mus m 1, which was up to 1700 ng/ml. Results were reproducible within as well as between laboratories. Within laboratories, 94% of CCC were ≥ 0.90, and 80% of intra-laboratory results fell within a 10% coefficient of variance (CV%). Results between laboratories also showed highly significant positive correlations for all allergens (~0.95, p<0.001). Overall means of results were comparable, and inter-laboratory CV% for all allergens except Rat n 1 ranged between 17.6% and 26.6%. CONCLUSION: The data indicate that performance criteria for fluorescent multiplex array technology are reproducible within and between laboratories. Multiplex technology provides standardized and consistent allergen measurements that will streamline environmental exposure assessments in allergic disease.

Reassessment of omalizumab-dosing strategies and pharmacodynamics in inner-city children and adolescents.

BACKGROUND: Treatment regimens for omalizumab are guided by a dosing table that is based on total serum IgE and body weight. Limited data exist about onset and offset of omalizumab efficacy in children and adolescents or subgroups that most benefit from treatment. OBJECTIVES: Post hoc analyses were conducted to (1) examine patient characteristics of those eligible and ineligible for omalizumab, (2) describe onset of effect after initiation of omalizumab and offset of treatment effect after stopping therapy, and (3) determine whether the efficacy differs by age, asthma severity, dosing regimen, and prespecified biomarkers. METHODS: Inner-city children and adolescents with persistent allergic asthma were enrolled in the Inner-City Anti-IgE Therapy for Asthma trial that compared omalizumab with placebo added to guidelines-based therapy for 60 weeks. RESULTS: Two hundred ninety-three of 889 participants (33%) clinically suitable for omalizumab were ineligible for dosing according to a modified dosing table specifying IgE level and body weight criteria. Baseline symptoms were comparable among those eligible and ineligible to receive omalizumab, but other characteristics (rate of health care utilization and skin test results) differed. The time of onset of omalizumab effect was <30 days and time of offset was between 30 and 120 days. No difference in efficacy was noted by age or asthma severity, but high exhaled nitric oxide, blood eosinophils, and body mass index predicted efficacy. CONCLUSIONS: A significant portion of children and adolescents particularly suited for omalizumab because of asthma severity status may be ineligible due to IgE >1300 IU/mL. Omalizumab reduced asthma symptoms and exacerbations rapidly; features associated with efficacy can be identified to guide patient selection.

Development and validation of the Composite Asthma Severity Index--an outcome measure for use in children and adolescents.

BACKGROUND: Asthma severity is reflected in many aspects of the disease, including impairment and future risks, particularly for exacerbations. According to the Expert Panel Report 3: Guidelines for the Diagnosis and Management of Asthma, however, to assess more comprehensively the severity of asthma the level of current treatment needed to maintain a level of control should be included. OBJECTIVE: Development and validation of a new instrument, the Composite Asthma Severity Index (CASI), which can quantify disease severity by taking into account impairment, risk, and the amount of medication needed to maintain control. At present, there is no instrument available to measure and assess the multidimensional nature of asthma. METHODS: Twenty-six established asthma investigators, who are part of the National Institutes of Health-supported Inner City Asthma Consortium, participated in a modified Delphi consensus process to identify and weight the dimensions of asthma. Factor analysis was performed to identify independent domains of asthma by using the Asthma Control Evaluation trial. CASI was validated by using the Inner City Anti-IgE Therapy for Asthma trial. RESULTS: CASI scores include 5 domains: day symptoms and albuterol use, night symptoms and albuterol use, controller treatment, lung function measures, and exacerbations. At Asthma Control Evaluation trial enrollment, CASI ranged from 0 to 17, with a mean of 6.2. CASI was stable, with minimal change in variance after 1 year of treatment. In external validation, CASI detected a 32% larger improvement than did symptoms alone. CONCLUSION: CASI retained its discriminatory ability even with low levels of symptoms reported after months of guidelines-directed care. Thus, CASI has the ability to determine the level of asthma severity and provide a composite clinical characterization of asthma.

Randomized trial of omalizumab (anti-IgE) for asthma in inner-city children.

BACKGROUND: Research has underscored the effects of exposure and sensitization to allergens on the severity of asthma in inner-city children. It has also revealed the limitations of environmental remediation and guidelines-based therapy in achieving greater disease control. METHODS: We enrolled inner-city children, adolescents, and young adults with persistent asthma in a randomized, double-blind, placebo-controlled, parallel-group trial at multiple centers to assess the effectiveness of omalizumab, as compared with placebo, when added to guidelines-based therapy. The trial was conducted for 60 weeks, and the primary outcome was symptoms of asthma. RESULTS: Among 419 participants who underwent randomization (at which point 73% had moderate or severe disease), omalizumab as compared with placebo significantly reduced the number of days with asthma symptoms, from 1.96 to 1.48 days per 2-week interval, a 24.5% decrease (P<0.001). Similarly, omalizumab significantly reduced the proportion of participants who had one or more exacerbations from 48.8 to 30.3% (P<0.001). Improvements occurred with omalizumab despite reductions in the use of inhaled glucocorticoids and long-acting beta-agonists. CONCLUSIONS: When added to a regimen of guidelines-based therapy for inner-city children, adolescents, and young adults, omalizumab further improved asthma control, nearly eliminated seasonal peaks in exacerbations, and reduced the need for other medications to control asthma. (Funded by the National Institute of Allergy and Infectious Diseases and Novartis; ClinicalTrials.gov number, NCT00377572.).

Asthma control, adiposity, and adipokines among inner-city adolescents.

BACKGROUND: There is an association between adiposity and asthma prevalence, but the relationship to asthma control is unclear. OBJECTIVES: We sought to understand the relationships among adiposity, sex, and asthma control in inner-city adolescents with asthma. METHODS: We prospectively followed 368 adolescents with moderate-to-severe asthma (ages 12-20 years) living in 10 urban areas for 1 year. Asthma symptoms and exacerbations were recorded, and pulmonary function and exhaled nitric oxide levels were measured every 6 weeks. Adiposity measures (body mass index [BMI] and dual-energy X-ray absorptiometric scans) were made, and blood was collected for measurement of allergy markers, adiponectin, leptin, TNF-alpha, IL-6, and C-reactive protein levels. RESULTS: More than 60% of female subjects and 50% of male subjects were above the 85th percentile of BMI for age. Higher BMI was associated with more symptom days (R = 0.18, P = .02) and exacerbations (R = 0.18, P = .06) among female subjects only. Adiponectin was inversely related to asthma symptoms (R = -0.18, P < .05) and exacerbations (R = -0.20, P < .05) and positively with FEV(1)/forced vital capacity ratio (R = 0.15, P < .05) in male subjects only independent of body size. There was no relationship between adiposity or adipokines and total IgE levels, blood eosinophil counts, and exhaled nitric oxide levels. Dual-energy X-ray absorptiometry provided little additional value in relating adiposity to asthma outcome in this population of adolescents. CONCLUSION: Adiposity is associated with poorer asthma control in female subjects. Adiponectin is associated with improved asthma control in male subjects.

Differential effects of outdoor versus indoor fungal spores on asthma morbidity in inner-city children.

BACKGROUND: Although sensitization to fungal allergens is prevalent in inner-city children with asthma, the relationship between fungal exposure and morbidity is poorly understood. OBJECTIVE: We examined relationships between fungal sensitization, exposure, and asthma morbidity in inner-city children. METHODS: Participants were 5 to 11 years old and enrolled in the Inner-City Asthma Study. This report includes the subset of children with at least 1 positive skin test (PST) response to a fungal allergen extract; for these children, indoor and outdoor airborne culturable fungi levels were measured at baseline and throughout the 2-year study. Asthma morbidity measures were collected prospectively. The primary outcome was symptom days per 2 weeks. RESULTS: At baseline, children with a PST response to a fungal allergen extract had significantly more symptom days compared with those without a PST response to any fungal allergen extract (6.3 vs 5.7 days per 2 weeks, P = .04). During the study, increases in total fungal exposure and indoor Penicillium species exposure were associated with increases in symptom days and asthma-related unscheduled visits. Indoor exposures to total fungi and to Penicillium species were associated with significant increases in unscheduled visits, even after controlling for outdoor fungal levels. Adverse effects associated with exposure to a specific fungus were stronger among children with PST responses to that fungal allergen extract compared with those seen in children with negative skin test responses. CONCLUSION: Outdoor fungal exposure is primarily associated with increased asthma symptoms and increased risk of exacerbations in this population.

Total IgE levels and asthma prevalence in the US population: results from the National Health and Nutrition Examination Survey 2005-2006.

BACKGROUND: The inability to measure IgE-based sensitivity to all allergens has limited our understanding of what portion of asthma is related to IgE. Total IgE measurement can potentially overcome this limitation. OBJECTIVE: We sought to determine the association between total IgE levels and asthma. METHODS: The National Health and Nutrition Examination Survey 2005-2006 examined a representative sample of the US population 6 years of age and older. RESULTS: The median total IgE level was 40.8 kU/L (interquartile range, 15.5-114 kU/L). Total IgE levels varied with age, sex, race/ethnicity, serum cotinine level, body size, and socioeconomic status. The prevalence of current asthma was 8.8%. The prevalence of atopy was 42.5%, as defined by 15 specific IgEs. The adjusted odds ratio (OR) for asthma with a 10-fold increase in total IgE level was 2.18 (95% CI, 1.66-2.87). Total IgE level predicted asthma only among atopic subjects (OR, 2.41; 95% CI, 1.62-3.60) and not among nonatopic subjects (OR, 1.11; 95% CI, 0.72-1.71; interaction P = .005). Among atopic subjects, the association between total IgE level and asthma became stronger as the number of positive specific IgE test results increased. Asthma was present at even the lowest levels of total IgE, regardless of atopic status. Approximately 92% of atopic subjects were identified by 6 specific IgEs, but to increase the identification to more than 99% required 11 specific IgEs. CONCLUSION: Total IgE levels are associated with asthma only among persons who have positive results for at least 1 allergen-specific IgE. Asthma independent of IgE is not uncommon in the US population. The complete identification of atopic subjects in a population requires a large panel of allergen-specific IgEs.

Effectiveness of educational and behavioral asthma interventions.

In this article we discuss studies of individualized and community-based interventions for control of asthma in children. We posit that successful programs share 8 common characteristics: (1) recognition of the multiple factors affecting childhood asthma; (2) careful assessment of participants' risk factors and needs; (3) tailoring of program elements to address participants' risk factors and needs; (4) consideration of both physical and social environments; (5) use of sound learning and change theories; (6) family involvement; (7) focus on children with the most serious disease; and (8) selection of delivery venues at which learning can be optimized. Challenges for moving practice and research forward also are presented.

State of childhood asthma and future directions conference: overview and commentary.

The Merck Childhood Asthma Network, Inc conference titled "State of Childhood Asthma and Future Directions: Strategies for Implementing Best Practices" was held December 13 to 14, 2006. Here we summarize the presentations and recommendations for systems approaches from that conference and discuss current asthma care.

Effect of mouse allergen and rodent environmental intervention on asthma in inner-city children.

BACKGROUND: Mouse allergens are prevalent in inner-city households, and increasing levels of exposure are associated with sensitization in children with asthma. OBJECTIVES: To examine mouse allergen sensitization and exposure in inner-city children, mouse allergen as an independent risk factor for asthma morbidity, and the efficacy of a rodent environmental intervention. METHODS: We conducted a subanalysis of children with asthma aged 5 to 11 years enrolled in the Inner-City Asthma Study. After randomization, 150 participants received a home rodent-specific environmental intervention. Asthma morbidity measures were obtained bimonthly. Bedroom dust was collected and analyzed for Mus m 1 at baseline and every 6 months for 2 years. RESULTS: Twenty-two percent of children tested positive to mouse. Most bedrooms (80%) had detectable mouse allergen. Sensitization occurred at low levels of exposure. Sensitization and exposure were associated with increased asthma morbidity, including hospitalizations. Mouse allergen levels on the bedroom floor decreased 27.3% (95% confidence interval, -46.1% to -1.9%) in intervention homes. Mouse allergen reduction was associated with less missed school, sleep disruption, and caretaker burden but not symptoms or medical utilization. CONCLUSIONS: Mouse allergen is prevalent in inner-city homes. Sensitization seems to occur at low levels of exposure. Mouse allergen is an independent risk factor for asthma morbidity. The described environmental intervention reduced mouse allergen levels and asthma-related sleep and activity disturbance.

Health effects of indoor nitrogen dioxide and passive smoking on urban asthmatic children.

BACKGROUND: Nitrogen dioxide (NO(2)) and environmental tobacco smoke (ETS) have been associated with adverse respiratory effects. OBJECTIVE: We sought to assess the effect of NO(2) and ETS on asthma morbidity among children in inner-city environments. METHODS: Asthmatic children between the ages of 4 and 9 years had exposure to NO(2) and ETS measured by using Palmes tubes in the home and urinary cotinine. A baseline interview and telephone assessments at 3, 6, and 9 months evaluated health service use, asthma symptoms, and peak flow rates. RESULTS: Gas stoves were present in 87.8% of 469 homes. The median level of indoor NO(2) was 29.8 ppb compared with the US national outdoor median of 18 ppb. Of 1444 children, 48% had urinary cotinine/creatinine ratios of greater than 30 ng/mg. The median level of the cotinine/creatinine ratio was 42.4 ng/mg in smoking homes compared with 18.0 ng/mg in nonsmoking homes. The relative risk for asthma symptoms with increased NO(2) exposure was 1.75 (95% CI, 1.10-2.78) in children who did not have positive skin test responses. Higher NO(2) exposure resulted in lower peak flows during colder months (relative risk, 1.46; 95% CI, 1.07-1.97). Higher ETS exposure in colder months was weakly associated with lower peak flows (relative risk, 1.21; 95% CI, 0.99-1.47). There was no effect of ETS exposure on symptoms or use of health care services. CONCLUSION: Higher levels of indoor NO(2) are associated with increased asthma symptoms in nonatopic children and decreased peak flows. CLINICAL IMPLICATIONS: Interventions to reduce NO(2) exposure, such as venting of gas stoves, might help reduce asthma morbidity.

Classification of asthma severity in children: the contribution of pulmonary function testing.

BACKGROUND: Despite increasing awareness of the National Asthma Education and Prevention Program guidelines, the relative contribution of symptom frequency or pulmonary function to the recommended asthma severity levels remains poorly understood. OBJECTIVE: To determine whether adding lung function measurements to clinical history substantially changes the asthma severity classification, thereby influencing treatment decisions. DESIGN: Baseline data were studied from children enrolled in 2 multicenter studies: phase 1 of the National Cooperative Inner-City Asthma Study (1992-1994) (cohort 1) and the Inner-City Asthma Study (1998-2001) (cohort 2). SETTING: Fifteen (8 for cohort 1 and 7 for cohort 2) major metropolitan inner-city areas in the United States. PARTICIPANTS: Inner-city children aged 8 through 11 years with asthma. MAIN OUTCOME MEASURES: Proportion of children reclassified from less severe asthma categories based on symptom frequency into more severe categories because of lung function. RESULTS: Of children with symptoms of mild intermittent asthma, 22.8% in cohort 1 and 27.7% in cohort 2 would be reclassified as having either moderate or severe persistent asthma. Of children with symptoms of mild persistent asthma, 31.2% in cohort 1 and 33.3% in cohort 2 would be similarly reclassified. CONCLUSIONS: In 2 different studies of inner-city children with asthma, approximately one third of the participants were reclassified into higher National Asthma Education and Prevention Program asthma severity categories when pulmonary function was considered in addition to symptom frequency. This may have direct implications for the undertreatment of asthma.

A randomized clinical trial of clinician feedback to improve quality of care for inner-city children with asthma.

CONTEXT: Barriers impede translating recommendations for asthma treatment into practice, particularly in inner cities where asthma morbidity is highest. METHODS: The purpose of this study was to test the effectiveness of timely patient feedback in the form of a letter providing recent patient-specific symptoms, medication, and health service use combined with guideline-based recommendations for changes in therapy on improving the quality of asthma care by inner-city primary care providers and on resultant asthma morbidity. This was a randomized, controlled clinical trial in 5- to 11-year-old children (n = 937) with moderate to severe asthma receiving health care in hospital- and community-based clinics and private practices in 7 inner-city urban areas. The caretaker of each child received a bimonthly telephone call to collect clinical information about the child's asthma. For a full year, the providers of intervention group children received bimonthly computer-generated letters based on these calls summarizing the child's asthma symptoms, health service use, and medication use with a corresponding recommendation to step up or step down medications. We measured the number and proportion of scheduled visits resulting in stepping up of medications, asthma symptoms (2-week recall), and health care use (2-month recall). RESULTS: In this population, only a modest proportion of children whose symptoms warranted a medication increase actually had a scheduled visit to reevaluate their asthma treatment. However, in the 2-month interval after receipt of a step-up letter, 17.1% of the letters were followed by scheduled visits in the intervention group compared with scheduled visits 12.3% of the time by the control children with comparable clinical symptoms. Asthma medications were stepped up when indicated after 46.0% of these visits in the intervention group compared with 35.6% in the control group, and when asthma symptoms warranted a step up in therapy, medication changes occurred earlier among the intervention children. Among children whose medications were stepped up at any time during the 12-month study period, those in the intervention group experienced 22.1% fewer symptom days and 37.9% fewer school days missed. The intention-to-treat analysis showed no difference over the intervention year in the number of symptom days, yet there was a trend toward fewer days of limited activity and a significant decrease in emergency department visits by the intervention group compared with controls. This 24% drop in emergency department visits resulted in an intervention that was cost saving in its first year. CONCLUSIONS: Patient-specific feedback to inner-city providers increased scheduled asthma visits, increased asthma visits in which medications were stepped up when clinically indicated, and reduced emergency department visits.