Latent Class Analysis Identified Children at Risk for Asthma Exacerbations

In children at risk for asthma exacerbations, the use of latent class analysis (LCA) helped identify 4 groups that differed with respect to demographic features, sensitization and type 2 inflammatory markers, previous exacerbation severity and healthcare use, and lung function.

Researchers conducted a study in school-age participants who were recruited from the emergency department, hospital wards, and asthma clinics of Children’s Healthcare of Atlanta at Egleston Hospital in Georgia, as well as through community-based advertisements. Findings from the study were published in The Journal of Allergy and Clinical Immunology: In Practice.¹

Recognizing that pediatric patients at risk for asthma exacerbation are a heterogeneous group, the investigators sought to identify latent classes of children at risk for exacerbation of asthma and to establish whether latent class assignment might be useful in predicting future disease exacerbations. LCA was carried out in a total of 513 children between 6 and 17 years of age at risk for asthma exacerbation, with 31 variables covering demographics, medical history, symptoms, lung function, treatment, sensitization, and type 2 inflammation.  All participants were included in the LCA between January 1, 2004, and December 31, 2015.

Study inclusion criteria were as follows: physician-diagnosed asthma with evidence of either ≥12% reversibility in forced expiratory volume in 1 second (FEV₁) relative to baseline or airway hyperresponsiveness, evidenced by a provocative concentration of methacholine resulting in a 20% decline in FEV₁ of ≤16 mg/mL; and a previous asthma exacerbation requiring treatment with systemic corticosteroids within the past 12 months or uncontrolled asthma per treatment guidelines.²

The primary study outcome was the proportion of participants within each of the 4 latent classes with any asthma exacerbation that required treatment with systemic corticosteroids within 12 months following the study visit. The secondary study outcome was the time to the first asthma exacerbation.

Results showed that asthma exacerbations were reported in 22.4% of participants in class 1 (lesser sensitization with normal lung function); 27.9% of those in class 2 (lesser sensitization with prior severe exacerbation and normal lung function); 45.3% of participants in class 3 (multiple sensitization with reversible airflow limitation); and 64.3% of those in class 4 (multiple sensitization with partially reversible airflow limitation; P <.001).

The time to asthma exacerbation followed similar trends as well, and was the shortest in patients in the latent classes with multiple sensitization and airflow limitation (P <.001). These study outcomes were driven almost entirely by children with exacerbation-prone asthma, which was defined as ≥3 disease exacerbations in the prior year, all of whom were present in each class but were represented most strongly in patients in classes 3 and 4.

The investigators concluded that sensitization, previous exacerbation severity, and lung function variables may be especially beneficial in the identification of those children who are at the greatest risk for future asthma exacerbations.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

References

1. Grunwell JR, Gillespie S, Morris CR, Fitzpatrick AM. Latent class analysis of school-age children at risk for asthma exacerbation [published online March 17, 2020]. J Allergy Clin Immunol Pract. doi:10.1016/j.jaip.2020.03.005

2. National Asthma Education and Prevention Program. Expert Panel Report (EPR-3): Guidelines for the Diagnosis and Management of Asthma–Summary Report. J Allergy Clin Immunol. 2007;120(5 suppl):S94-S138.