Research Examines Factors That Complicate Pediatric Asthma

Included among the abstracts prepared and published for the American Academy of Allergy, Asthma & Immunology (AAAAI) 2020 Annual Meeting are several that looked at the clinical and psychosocial factors that complicate asthma in pediatric patients. A few are highlighted here.

Levels of Interleukin-6 in Children Living in Inner Cities

Children who live in inner cities with asthma and who produce high levels of interleukin-6 (IL-6) are more likely to be obese and have worse asthma symptoms, according to researchers; they noted that both asthma and obesity have risen in urban children and that the incidence and severity of asthma is higher in obese populations.

IL-6, produced by adipocytes, or fat cells, is a biomarker of systemic inflammation and metabolic dysfunction; researchers hypothesized that plasma IL-6 levels are associated with increased body mass index (BMI), asthma symptoms, and metabolic inflammatory markers, such as C-reactive protein (CRP) and neutrophils, in inner-city children.

The School Inner-City Asthma Studies 1 and 2, a long-running study funded by the National Institutes of Health, enrolled students with asthma from urban elementary schools.

The baseline evaluation included a blood draw, measurement of body mass index (BMI), spirometry, fractional exhaled nitric oxide (F_ENO), and an assessment of asthma symptoms. They also assessed the relationships between IL-6 levels and BMI percentile, inflammatory markers, and asthma outcomes.

The analysis included 200 predominantly black (27%) or Hispanic (42%) students. Three IL-6 groups were defined based on 75th percentile:

• No IL-6 (n = 101) with undetectable IL-6 levels
• Low IL-6 (n = 45) with IL-6 of 0.02-0.27 pg/mL
• High IL-6 (n = 51) with IL-6 of at least 0.28 pg/mL

The high IL-6 group had significantly higher BMI, CRP, white blood cell, and neutrophil counts (P <.01 compared with no IL-6; P <.05 compared with low IL-6).

In addition, high IL-6 was associated with an increased number of asthma symptom days compared with no or low IL-6 (P <.05).

However, no association was found between IL-6 and eosinophil count, F_ENO, or spirometry outcomes.

Predicting Development of Severe Asthma Into Adulthood

Another abstract looked at factors that might predict the development of severe asthma in late adolescence after starting out with mild asthma in childhood.

Lung function was the only significant childhood predictor of severe asthma from late adolescence through early adulthood, the researchers wrote, highlighting the importance of intervening to preserve lung function early in childhood in order to prevent and reverse later disease.

The Childhood Asthma Management Program (CAMP) is the largest and longest asthma clinical trial in 1041 children aged 5 to 12 years with mild to moderate asthma. Researchers evaluated 682 CAMP participants who had analyzable data in late adolescence (age 17-19 years) through early adulthood (age 21-23 years).

Multinomial logistic regression analysis with backwards elimination was used to investigate clinical features, biomarkers, and lung function predictive of severe asthma. Severe asthma was based on criteria set by the National Asthma Education and Prevention Program.

Of the 682 participants, 34.8% and 22.1% had severe asthma in late adolescence and early adulthood, respectively. Only 11% of the total 682 patients had asthma that stayed severe.

Prebronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV₁/FVC) ratio at baseline and duration of asthma were associated with persistence of severe asthma into early adulthood.

For every 5-point increase in FEV₁/FVC ratio at baseline, the odds of a person remaining severe could be as low as 33%. For every year increase of asthma duration, the odds of a person remaining severe could be as high as 18%.

Teenagers and Nonadherence

Another abstract examined the topic of nonadherence in adolescent patients, which is a significant risk factor for poor asthma outcome.

Researchers conducted a psychosocial assessment on children with asthma aged 8 to 18 years, who were treated with daily inhaled corticosteroid (ICS) at a pediatric allergy clinic in Thailand from April 2019 to January 2020.

Interviews collected demographic information, asthma status and education, ICS adherence, disease perception, and outcome expectation. Psychological assessment was performed by using a children’s depression inventory, a screening for child anxiety-related disorders, and a Rosenberg self-esteem scale.

Preliminary results from 106 patients (mean [SD] age = 12 [3] years; 70.8% male) showed that most had mild to moderate and controlled asthma (mean [SD] asthma control test score of 24 [2]). Mean (SD) ICS adherence was 74.6% (27.8%).

Of 73 patients who missed ICS doses, nearly 59% of them reported intentional nonadherence; the majority (95.3%) felt the burden of using ICS outweighed the benefits.

Moreover, only 12.5% of patients knew that asthma caused airway spasm, and 68.9% realized the difference between controller medicines and acute relief medicines. Sixteen (15.8%) and 24 (24%) patients misperceived their control status and severity, respectively.

Patients who expected good asthma outcomes from following their asthma action plan had significantly high (>75%) medication adherence (P = .039).

In addition, 21% had significant depression, 23% had clinical range for anxiety, and 6% had low self-esteem, but none were related to adherence rate. The researchers wrote that the occurrence of depression and anxiety were higher than expected and that the expectation of a patient’s asthma outcome expectation may predict better adherence.