Gene-based association study of rare variants in children of diverse ancestries implicates TNFRSF21 in the development of allergic asthma.

BACKGROUND: Most genetic studies of asthma and allergy have focused on common variation in individuals primarily of European ancestry. Studying the role of rare variation in quantitative phenotypes and in asthma phenotypes in populations of diverse ancestries can provide additional, important insights into the development of these traits. OBJECTIVE: We sought to examine the contribution of rare variants to different asthma- or allergy-associated quantitative traits in children with diverse ancestries and explore their role in asthma phenotypes. METHODS: We examined whole-genome sequencing data from children participants in longitudinal studies of asthma (n = 1035; parent-identified as 67% Black and 25% Hispanic) to identify rare variants (minor allele frequency < 0.01). We assigned variants to genes and tested for associations using an omnibus variant-set test between each of 24,902 genes and 8 asthma-associated quantitative traits. On combining our results with external data on predicted gene expression in humans and mouse knockout studies, we identified 3 candidate genes. A burden of rare variants in each gene and in a combined 3-gene score was tested for its associations with clinical phenotypes of asthma. Finally, published single-cell gene expression data in lower airway mucosal cells after allergen challenge were used to assess transcriptional responses to allergen. RESULTS: Rare variants in USF1 were significantly associated with blood neutrophil count (P = 2.18 × 10-7); rare variants in TNFRSF21 with total IgE (P = 6.47 × 10-6) and PIK3R6 with eosinophil count (P = 4.10 × 10-5) reached suggestive significance. These 3 findings were supported by independent data from human and mouse studies. A burden of rare variants in TNFRSF21 and in a 3-gene score was associated with allergy-related phenotypes in cohorts of children with mild and severe asthma. Furthermore, TNFRSF21 was significantly upregulated in bronchial basal epithelial cells from adults with allergic asthma but not in adults with allergies (but not asthma) after allergen challenge. CONCLUSIONS: We report novel associations between rare variants in genes and allergic and inflammatory phenotypes in children with diverse ancestries, highlighting TNFRSF21 as contributing to the development of allergic asthma.

SNAP: Supportive non-invasive ventilation for acute chest syndrome prevention for hospitalized children with sickle cell disease: Perspectives of patients, parents, and the healthcare team.

RATIONALE: Acute chest syndrome (ACS) often develops during hospitalizations for sickle cell disease (SCD) vaso-occlusive episodes and may be triggered by a combination of chest wall splinting, opioid use, hypoventilation, and atelectasis. In 2017, Boston Medical Center's general pediatric inpatient unit instituted the novel use of bi-level positive airway pressure (BiPAP) as "supportive non-invasive ventilation for ACS prevention" (SNAP) to prevent ACS and respiratory decompensation. OBJECTIVE: The goals of this qualitative study were to identify perceived benefits, harms, facilitators, and barriers to use of SNAP. METHODS: We conducted semi-structured key informant interviews at three sites with different levels of SNAP implementation (Site 1: extensive implementation; Site 2: limited implementation; Site 3: not yet implemented) regarding experiences with and/or perceptions of SNAP. Interviews and coding were guided by the Promoting Action on Research Implementation in Health Services (PARiHS) framework. RESULTS: Thirty-four participants (physicians, nurses, respiratory therapists, child life specialists, psychologists, youth with SCD, and parents) completed interviews. Major themes included: (i) participants perceive BiPAP as effective at preventing ACS, and for those with medically stable ACS, for preventing respiratory decompensation. (ii) BiPAP use is appropriate on the general pediatric inpatient unit for medically stable patients with SCD. (iii) Improving the patient experience is the most important factor to optimize acceptance of BiPAP by patients and families. CONCLUSION/FUTURE DIRECTIONS: SNAP is perceived as effective and appropriate for hospitalized pediatric patients with SCD. Improving the patient experience is the biggest challenge. These data will inform a future protocol for a multicenter hybrid effectiveness/implementation trial of SNAP.

Race and Ethnicity in Pulmonary Function Test Interpretation: An Official American Thoracic Society Statement.

Current American Thoracic Society (ATS) standards promote the use of race and ethnicity-specific reference equations for pulmonary function test (PFT) interpretation. There is rising concern that the use of race and ethnicity in PFT interpretation contributes to a false view of fixed differences between races and may mask the effects of differential exposures. This use of race and ethnicity may contribute to health disparities by norming differences in pulmonary function. In the United States and globally, race serves as a social construct that is based on appearance and reflects social values, structures, and practices. Classification of people into racial and ethnic groups differs geographically and temporally. These considerations challenge the notion that racial and ethnic categories have biological meaning and question the use of race in PFT interpretation. The ATS convened a diverse group of clinicians and investigators for a workshop in 2021 to evaluate the use of race and ethnicity in PFT interpretation. Review of evidence published since then that challenges current practice and continued discussion concluded with a recommendation to replace race and ethnicity-specific equations with race-neutral average reference equations, which must be accompanied with a broader re-evaluation of how PFTs are used to make clinical, employment, and insurance decisions. There was also a call to engage key stakeholders not represented in this workshop and a statement of caution regarding the uncertain effects and potential harms of this change. Other recommendations include continued research and education to understand the impact of the change, to improve the evidence for the use of PFTs in general, and to identify modifiable risk factors for reduced pulmonary function.

Mepolizumab for urban children with exacerbation-prone eosinophilic asthma in the USA (MUPPITS-2): a randomised, double-blind, placebo-controlled, parallel-group trial.

BACKGROUND: Black and Hispanic children living in urban environments in the USA have an excess burden of morbidity and mortality from asthma. Therapies directed at the eosinophilic phenotype reduce asthma exacerbations in adults, but few data are available in children and diverse populations. Furthermore, the molecular mechanisms that underlie exacerbations either being prevented by, or persisting despite, immune-based therapies are not well understood. We aimed to determine whether mepolizumab, added to guidelines-based care, reduced the number of asthma exacerbations during a 52-week period compared with guidelines-based care alone. METHODS: This is a randomised, double-blind, placebo-controlled, parallel-group trial done at nine urban medical centres in the USA. Children and adolescents aged 6-17 years, who lived in socioeconomically disadvantaged neighbourhoods and had exacerbation-prone asthma (defined as ≥two exacerbations in the previous year) and blood eosinophils of at least 150 cells per µL were randomly assigned 1:1 to mepolizumab (6-11 years: 40 mg; 12-17 years: 100 mg) or placebo injections once every 4 weeks, plus guideline-based care, for 52 weeks. Randomisation was done using a validated automated system. Participants, investigators, and the research staff who collected outcome measures remained masked to group assignments. The primary outcome was the number of asthma exacerbations that were treated with systemic corticosteroids during 52 weeks in the intention-to-treat population. The mechanisms of treatment response were assessed by study investigators using nasal transcriptomic modular analysis. Safety was assessed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT03292588. FINDINGS: Between Nov 1, 2017, and Mar 12, 2020, we recruited 585 children and adolescents. We screened 390 individuals, of whom 335 met the inclusion criteria and were enrolled. 290 met the randomisation criteria, were randomly assigned to mepolizumab (n=146) or placebo (n=144), and were included in the intention-to-treat analysis. 248 completed the study. The mean number of asthma exacerbations within the 52-week study period was 0·96 (95% CI 0·78-1·17) with mepolizumab and 1·30 (1·08-1·57) with placebo (rate ratio 0·73; 0·56-0·96; p=0·027). Treatment-emergent adverse events occurred in 42 (29%) of 146 participants in the mepolizumab group versus 16 (11%) of 144 participants in the placebo group. No deaths were attributed to mepolizumab. INTERPRETATION: Phenotype-directed therapy with mepolizumab in urban children with exacerbation-prone eosinophilic asthma reduced the number of exacerbations. FUNDING: US National Institute of Allergy and Infectious Diseases and GlaxoSmithKline.

Appropriate inhaler use in children with asthma: barriers and opportunities through the lens of the socio-ecological model.

Objective: Proper use of inhaled medications is essential for management of asthma, as inhaled therapies are recommended as first-line for both prevention and treatment of asthma symptoms. Optimizing adherence requires identifying and understanding multiple layers of systemic complexity to obtaining and using these therapies and offering specific solutions to address these barriers. Bronfenbrenner's socio-ecological model provides a framework for examining multilevel systems - both internal and external - that contribute to the management of childhood asthma. The four levels in this model consist of factors related to the individual, interpersonal relationships, organizational entities, and societal structures and rules. This narrative review identifies influences and factors related to asthma inhaler adherence by each level and offers evidence-based solutions to each obstacle.Data Sources: We conducted PubMed searches to identify relevant articles for barriers and solutions impacting asthma control at each level of the socio-ecological model.Study Selection: Common barriers to asthma control at each model level were identified. Pertinent studies for each barrier were identified and reviewed by the writing group for inclusion into the narrative review.Results: For each level of the socio-ecological model, three primary issues were identified based on the literature review. Approaches for addressing each issue in an evidence-based, systematic fashion are presented.Conclusion: Understanding the obstacles and potential interventions to achieve proper use of inhaled medications is a critical step necessary to develop and implement systematic solutions aimed at improving asthma control and morbidity for the more than 6 million affected children in the United States.

WITHDRAWN: Update in Asthma 2021.

Ahead of Print article withdrawn by publisher.

SNAP: Supportive noninvasive ventilation for acute chest syndrome prevention in children with sickle cell disease.

BACKGROUND: Acute chest syndrome (ACS) is a leading cause of morbidity and mortality among children with sickle cell disease (SCD). Preventing hypoxemia by optimizing lung aeration during sleep remains a challenge. OBJECTIVES: To explore safety, feasibility, and tolerability of noninvasive, bi-level positive airway pressure ventilation (BiPAP) as preventative, supportive care for hospitalized, medically stable children with SCD on a general pediatric inpatient unit. METHODS: Retrospective chart review of patients ≤22 years of age with SCD admitted to the general pediatric inpatient unit from February 1, 2017 to March 1, 2020 for whom BiPAP was recommended as supportive care. Hospitalizations were excluded if patients were admitted to the pediatric intensive care unit (PICU), required BiPAP for respiratory failure, or used BiPAP at home for obstructive sleep apnea. RESULTS: Twenty-three patients had 53 hospitalizations in which BiPAP was recommended. Fifty-two (98%) hospitalizations included acute SCD pain. Indications for BiPAP included prior ACS (94%), chest or back pain (79%), and/or oxygen desaturation (66%). On 17 occasions, patients already had mild to moderate ACS but were stable when BiPAP was recommended. BiPAP was used successfully during 75% of hospitalizations for a median of two nights. There were no adverse effects associated with BiPAP. PICU transfer for respiratory support occurred during three hospitalizations. In 26 hospitalizations of children at risk for ACS who tolerated BiPAP, 23 (88%) did not develop ACS. CONCLUSIONS: BiPAP is safe, feasible, and well tolerated as supportive care for hospitalized children with SCD. Next steps include an intervention trial to further assess the efficacy of BiPAP on ACS prevention.

Rhinitis in children and adolescents with asthma: Ubiquitous, difficult to control, and associated with asthma outcomes.

BACKGROUND: Rhinitis and asthma are linked, but substantial knowledge gaps in this relationship exist. OBJECTIVE: We sought to determine the prevalence of rhinitis and its phenotypes in children and adolescents with asthma, assess symptom severity and medication requirements for rhinitis control, and investigate associations between rhinitis and asthma. METHODS: Seven hundred forty-nine children with asthma participating in the Asthma Phenotypes in the Inner-City study received baseline evaluations and were managed for 1 year with algorithm-based treatments for rhinitis and asthma. Rhinitis was diagnosed by using a questionnaire focusing on individual symptoms, and predefined phenotypes were determined by combining symptom patterns with skin tests and measurement of serum specific IgE levels. RESULTS: Analyses were done on 619 children with asthma who completed at least 4 of 6 visits. Rhinitis was present in 93.5%, and phenotypes identified at baseline were confirmed during the observation/management year. Perennial allergic rhinitis with seasonal exacerbations was most common (34.2%) and severe. Nonallergic rhinitis was least common (11.3%) and least severe. The majority of children remained symptomatic despite use of nasal corticosteroids with or without oral antihistamines. Rhinitis was worse in patients with difficult-to-control versus easy-to-control asthma, and its seasonal patterns partially corresponded to those of difficult-to-control asthma. CONCLUSION: Rhinitis is almost ubiquitous in urban children with asthma, and its activity tracks that of lower airway disease. Perennial allergic rhinitis with seasonal exacerbations is the most severe phenotype and most likely to be associated with difficult-to-control asthma. This study offers strong support to the concept that rhinitis and asthma represent the manifestations of 1 disease in 2 parts of the airways.

Distinct nasal airway bacterial microbiotas differentially relate to exacerbation in pediatric patients with asthma.

BACKGROUND: In infants, distinct nasopharyngeal bacterial microbiotas differentially associate with the incidence and severity of acute respiratory tract infection and childhood asthma development. OBJECTIVE: We hypothesized that distinct nasal airway microbiota structures also exist in children with asthma and relate to clinical outcomes. METHODS: Nasal secretion samples (n = 3122) collected after randomization during the fall season from children with asthma (6-17 years, n = 413) enrolled in a trial of omalizumab (anti-IgE) underwent 16S rRNA profiling. Statistical analyses with exacerbation as the primary outcome and rhinovirus infection and respiratory illnesses as secondary outcomes were performed. Using A549 epithelial cells, we assessed nasal isolates of Moraxella, Staphylococcus, and Corynebacterium species for their capacity to induce epithelial damage and inflammatory responses. RESULTS: Six nasal airway microbiota assemblages, each dominated by Moraxella, Staphylococcus, Corynebacterium, Streptococcus, Alloiococcus, or Haemophilus species, were observed. Moraxella and Staphylococcus species-dominated microbiotas were most frequently detected and exhibited temporal stability. Nasal microbiotas dominated by Moraxella species were associated with increased exacerbation risk and eosinophil activation. Staphylococcus or Corynebacterium species-dominated microbiotas were associated with reduced respiratory illness and exacerbation events, whereas Streptococcus species-dominated assemblages increased the risk of rhinovirus infection. Nasal microbiota composition remained relatively stable despite viral infection or exacerbation; only a few taxa belonging to the dominant genera exhibited relative abundance fluctuations during these events. In vitro, Moraxella catarrhalis induced significantly greater epithelial damage and inflammatory cytokine expression (IL-33 and IL-8) compared with other dominant nasal bacterial isolates tested. CONCLUSION: Distinct nasal airway microbiotas of children with asthma relate to the likelihood of exacerbation, rhinovirus infection, and respiratory illnesses during the fall season.

Aeroallergen sensitization predicts acute chest syndrome in children with sickle cell anaemia.

Asthma is associated with higher rates of acute chest syndrome (ACS) and vaso-occlusive pain episodes among children with sickle cell anaemia (SCA). Aeroallergen sensitization is a risk factor for asthma. We hypothesized that aeroallergen sensitization is associated with an increased incidence of hospitalizations for ACS and pain. Participants in a multicentre, longitudinal cohort study, aged 4-18 years with SCA, underwent skin prick testing to ten aeroallergens. ACS and pain episodes were collected from birth until the end of the follow-up period. The number of positive skin tests were tested for associations with prospective rates of ACS and pain. Multivariable models demonstrated additive effects of having positive skin tests on future rates of ACS (incidence rate ratio (IRR) for each positive test 1·23, 95% confidence interval [CI] 1·11-1·36, P < 0·001). Aeroallergen sensitization was not associated with future pain (IRR 1·14, 95%CI 0·97-1·33, P = 0·11). Our study demonstrated that children with SCA and aeroallergen sensitization are at increased risk for future ACS. Future research is needed to determine whether identification of specific sensitizations and allergen avoidance and treatment reduce the risk of ACS for children with SCA.

Caring for Young Children with Asthma: Perspectives from Urban Community Health Centers.

Asthma disproportionately affects low-income, minority youth, with notable disparities among children <5 years of age. Understanding the perceptions of urban community health centers (CHCs) regarding treating young children with asthma could improve care for these patients. This study uses data from semi-structured focus groups with staff from eight urban CHCs. Themes emerged in three domains. Within the parent/family domain, providers noted low rates of follow-up visits, low health literacy, and-for young children specifically-misunderstanding about the diagnosis. At the CHC level, providers needed more staff, space, and comfort with applying the guidelines to infants and young children. CHCs reported asthma registries, population health oversight, and an asthma champion improved care. At the system level, providers wanted improved communication with emergency departments and community outreach programs. Reducing these multi-level barriers may improve care.

Exhaled nitric oxide: Not associated with asthma, symptoms, or spirometry in children with sickle cell anemia.

BACKGROUND: The significance of fractional exhaled nitric oxide (Feno) levels in children with sickle cell anemia (SCA) is unclear, but increased levels can be associated with features of asthma and thus increased morbidity. OBJECTIVES: We sought to determine factors associated with Feno and whether Feno levels are associated with increased rates of acute chest syndrome (ACS) and pain. METHODS: All participants had SCA, were part of the prospective observational Sleep and Asthma Cohort study, and had the following assessments: Feno levels, spirometry, blood samples analyzed for hemoglobin, white blood cell counts, eosinophil counts and total serum IgE levels, questionnaires about child medical and family history, and review of medical records. RESULTS: The analytic sample included 131 children with SCA (median age, 11.2 years; age range, 6-18 years) followed for a mean of 16.2 years, including a mean of 5.1 years after baseline Feno data measurements. In multivariable analyses higher Feno levels were associated with ln(IgE) levels (P < .001) and the highest quartile of peripheral eosinophil counts (P = .03) but not wheezing symptoms, baseline spirometric indices, or response to bronchodilator. Multivariable analyses identified that the incident rate of ACS was associated with ln(Feno) levels (P = .03), as well as male sex (P = .025), wheezing causing shortness of breath (P = .002), and ACS at less than 4 years of age (P < .001). Feno levels were not associated with future pain episodes. CONCLUSIONS: Steady-state Feno levels were not associated with an asthma diagnosis, wheezing symptoms, lung function measures, or prior sickle cell morbidity but were associated with markers of atopy and increased risk of future ACS events.

Distinguishing characteristics of difficult-to-control asthma in inner-city children and adolescents.

BACKGROUND: Treatment levels required to control asthma vary greatly across a population with asthma. The factors that contribute to variability in treatment requirements of inner-city children have not been fully elucidated. OBJECTIVE: We sought to identify the clinical characteristics that distinguish difficult-to-control asthma from easy-to-control asthma. METHODS: Asthmatic children aged 6 to 17 years underwent baseline assessment and bimonthly guideline-based management visits over 1 year. Difficult-to-control and easy-to-control asthma were defined as daily therapy with 500 µg of fluticasone or greater with or without a long-acting ß-agonist versus 100 µg or less assigned on at least 4 visits. Forty-four baseline variables were used to compare the 2 groups by using univariate analyses and to identify the most relevant features of difficult-to-control asthma by using a variable selection algorithm. Nonlinear seasonal variation in longitudinal measures (symptoms, pulmonary physiology, and exacerbations) was examined by using generalized additive mixed-effects models. RESULTS: Among 619 recruited participants, 40.9% had difficult-to-control asthma, 37.5% had easy-to-control asthma, and 21.6% fell into neither group. At baseline, FEV1 bronchodilator responsiveness was the most important characteristic distinguishing difficult-to-control asthma from easy-to-control asthma. Markers of rhinitis severity and atopy were among the other major discriminating features. Over time, difficult-to-control asthma was characterized by high exacerbation rates, particularly in spring and fall; greater daytime and nighttime symptoms, especially in fall and winter; and compromised pulmonary physiology despite ongoing high-dose controller therapy. CONCLUSIONS: Despite good adherence, difficult-to-control asthma showed little improvement in symptoms, exacerbations, or pulmonary physiology over the year. In addition to pulmonary physiology measures, rhinitis severity and atopy were associated with high-dose asthma controller therapy requirement.

Preseasonal treatment with either omalizumab or an inhaled corticosteroid boost to prevent fall asthma exacerbations.

BACKGROUND: Short-term targeted treatment can potentially prevent fall asthma exacerbations while limiting therapy exposure. OBJECTIVE: We sought to compare (1) omalizumab with placebo and (2) omalizumab with an inhaled corticosteroid (ICS) boost with regard to fall exacerbation rates when initiated 4 to 6 weeks before return to school. METHODS: A 3-arm, randomized, double-blind, double placebo-controlled, multicenter clinical trial was conducted among inner-city asthmatic children aged 6 to 17 years with 1 or more recent exacerbations (clincaltrials.gov #NCT01430403). Guidelines-based therapy was continued over a 4- to 9-month run-in phase and a 4-month intervention phase. In a subset the effects of omalizumab on IFN-α responses to rhinovirus in PBMCs were examined. RESULTS: Before the falls of 2012 and 2013, 727 children were enrolled, 513 were randomized, and 478 were analyzed. The fall exacerbation rate was significantly lower in the omalizumab versus placebo arms (11.3% vs 21.0%; odds ratio [OR], 0.48; 95% CI, 0.25-0.92), but there was no significant difference between omalizumab and ICS boost (8.4% vs 11.1%; OR, 0.73; 95% CI, 0.33-1.64). In a prespecified subgroup analysis, among participants with an exacerbation during the run-in phase, omalizumab was significantly more efficacious than both placebo (6.4% vs 36.3%; OR, 0.12; 95% CI, 0.02-0.64) and ICS boost (2.0% vs 27.8%; OR, 0.05; 95% CI, 0.002-0.98). Omalizumab improved IFN-α responses to rhinovirus, and within the omalizumab group, greater IFN-α increases were associated with fewer exacerbations (OR, 0.14; 95% CI, 0.01-0.88). Adverse events were rare and similar among arms. CONCLUSIONS: Adding omalizumab before return to school to ongoing guidelines-based care among inner-city youth reduces fall asthma exacerbations, particularly among those with a recent exacerbation.

Childhood pneumonia increases risk for chronic obstructive pulmonary disease: the COPDGene study.

BACKGROUND: Development of adult respiratory disease is influenced by events in childhood. The impact of childhood pneumonia on chronic obstructive pulmonary disease (COPD) is not well defined. We hypothesize that childhood pneumonia is a risk factor for reduced lung function and COPD in adult smokers. METHODS: COPD cases and control smokers between 45-80 years old from the United States COPDGene Study were included. Childhood pneumonia was defined by self-report of pneumonia at <16 years. Subjects with lung disease other than COPD or asthma were excluded. Smokers with and without childhood pneumonia were compared on measures of respiratory disease, lung function, and quantitative analysis of chest CT scans. RESULTS: Of 10,192 adult smokers, 854 (8.4%) reported pneumonia in childhood. Childhood pneumonia was associated with COPD (OR 1.40; 95% CI 1.17-1.66), chronic bronchitis, increased COPD exacerbations, and lower lung function: post-bronchodilator FEV1 (69.1 vs. 77.1% predicted), FVC (82.7 vs. 87.4% predicted), FEV1/FVC ratio (0.63 vs. 0.67; p < 0.001 for all comparisons). Childhood pneumonia was associated with increased airway wall thickness on CT, without significant difference in emphysema. Having both pneumonia and asthma in childhood further increased the risk of developing COPD (OR 1.85; 95% CI 1.10-3.18). CONCLUSIONS: Children with pneumonia are at increased risk for future smoking-related lung disease including COPD and decreased lung function. This association is supported by airway changes on chest CT scans. Childhood pneumonia may be an important factor in the early origins of COPD, and the combination of pneumonia and asthma in childhood may pose the greatest risk. CLINICAL TRIALS REGISTRATION: ClinicalTrials.gov, NCT00608764 (Active since January 28, 2008).

Increased risk of severe vaso-occlusive episodes after initial acute chest syndrome in children with sickle cell anemia less than 4 years old: Sleep and asthma cohort.

Previous studies have shown that the highest incidence of acute chest syndrome (ACS) in sickle cell disease occurs in children <4 years old, and a history of ACS at this age is a risk factor for future ACS episodes. However, the interval associated with the highest risk of subsequent ACS or severe pain is not known. Through this mixed retrospective-prospective observational study, the Sleep and Asthma Cohort, we sought to determine the interval after an initial ACS episode during which the majority of children <4 years old are rehospitalized for ACS or severe pain. The cumulative prevalence of rehospitalization for ACS or severe pain within 6 months, 1 years, and 2 years was calculated for children with an initial ACS episode <4 years old and compared to children with an initial ACS episode ≥4 years old. A total of 44.8% and 55.2% of participants had an initial ACS episode <4 years and ≥4 years old (Range: 4-17.7 years), respectively. At 1 year following the initial ACS episode, children <4 years old had a significantly higher cumulative prevalence of rehospitalizations for ACS or pain as compared to children ≥4 years of age, 62.5 and 39.1%, respectively (P = 0.009). After initial ACS episodes, the majority of children <4 years old will be rehospitalized for ACS or severe pain within one year, suggesting the need for a therapeutic intervention for this high-risk group.

Wheezing symptoms and parental asthma are associated with a physician diagnosis of asthma in children with sickle cell anemia.

OBJECTIVE: To identify factors associated with asthma associated with increased sickle cell anemia (SCA). STUDY DESIGN: Children with SCA (N = 187; mean age 9.6 years, 48% male) were classified as having "asthma" based on parent report of physician diagnosis plus prescription of asthma medication (n = 53) or "no asthma" based on the absence of these features (n = 134). Pain and acute chest syndrome (ACS) events were collected prospectively. RESULTS: Multiple variable logistic regression model identified 3 factors associated with asthma: parent with asthma (P = .006), wheezing causing shortness of breath (P = .001), and wheezing after exercise (P < .001). When ≥2 features were present, model sensitivity was 100%. When none of the features were present, model sensitivity was 0%. When only 1 feature was present, model sensitivity was also 0%, and presence of ≥2 of positive allergy skin tests, airway obstruction on spirometry, and bronchodilator responsiveness did not improve clinical utility. ACS incident rates were significantly higher in individuals with asthma than in those without asthma (incident rate ratio 2.21, CI 1.31-3.76), but pain rates were not (incident rate ratio 1.28, CI 0.78-2.10). CONCLUSIONS: For children with SCA, having a parent with asthma and specific wheezing symptoms are the best features to distinguish those with and without parent report of a physician diagnosis of asthma and to identify those at higher risk for ACS events. The value of treatment for asthma in the prevention of SCA morbidity needs to be studied.