Identification of asthma phenotypes in children

Characteristics of Allergic, Eosinophilic, and Overlapping Asthma Phenotypes Among Pediatric Patients with Current Asthma: A Cross-Sectional Study from Saudi Arabia

Purpose

Asthma is one of the most common chronic diseases affecting 10%-30% of children in Saudi Arabia. Although data exist on adult asthma phenotyping and endotyping in Saudi Arabia, little is known about asthma phenotypes in Saudi children.

Patients and Methods

This cross-sectional study enrolled pediatric patients diagnosed with bronchial asthma and followed in the pediatric pulmonology clinic of the Abha Maternity and Children Hospital between August 2021 and May 2023.

Results

A total of 321 children (aged 5-14 years) were analyzed. The population was classified into allergic [169 (52.6%)], eosinophilic [144 (44.9%)], and overlapping allergic and eosinophilic asthma [97 (30.2%)] phenotypes. Regarding asthma severity, 35.5%, 50.2%, and 14.3% were classified as mild, moderate, and severe, respectively. Of the 321 patients in the study, 124 (38.6%) had at least one asthma exacerbation that required hospitalization. The number of reported missed school days in the previous year was 1571 days [190 (59.2%) patients reported at least one missed school day]. The factors associated with the likelihood of uncontrolled asthma for all study participants included: emergency room (ER) visit last year (OR = 3.7, 95% CI:0.6-15.9]), overlapping eosinophilic and allergic (OR = 3.2, 95% CI = 1.8-5.9), and allergic phenotype (OR = 2.7, 95% CI = 1.3-5.4). The level of asthma control differed significantly among the three asthma phenotypes (p = 0.037).

Conclusion

Allergic asthma is the most prevalent asthma phenotype in this study, followed by the eosinophilic phenotype. The research has also shown that several factors predict uncontrolled asthma, including a family history of asthma, previous admission to the PICU, and previous hospitalization ever. There is, therefore, a definite need for multicenter cohort studies to better understand the phenotypes and endotypes of childhood asthma, as it could offer therapeutic and prognostic relevance.

Cohort profile: the West Sweden Asthma Study (WSAS): a multidisciplinary population-based longitudinal study of asthma, allergy and respiratory conditions in adults

PURPOSE

The West Sweden Asthma Study (WSAS) is a population-representative longitudinal study established to: (1) generate data on prevalence trends, incidence and remission of asthma, allergy and respiratory conditions, (2) elucidate on the risk and prognostic factors associated with these diseases, (3) characterise clinically relevant phenotypes of these diseases and (4) catalyse relevant mechanistic, genomic, genetic and translational investigations.

PARTICIPANTS

WSAS comprised of randomly selected individuals aged 16 to 75 years who are followed up longitudinally. The first stage involved a questionnaire survey (>42 000 participants) and was undertaken in 2008 and 2016. A random sample (about 8000) of participants in the initial survey undergoes extensive clinical investigations every 8 to 10 years (first investigations in 2009 to 2012, second wave currently ongoing). Measurements undertaken at the clinical investigations involve structured interviews, self-completed questionnaire on personality traits, physical measurements and extensive biological samples.

FINDINGS TO DATE

Some of our key findings have shown a 54% increase in the use of asthma medications between the 1990s and 2000s, primarily driven by a five-fold increase in the use of inhaled corticosteroids. About 36% of asthmatics expressed at least one sign of severe asthma indicator, with differential lung performance, inflammation and allergic sensitisation among asthmatics with different signs of severe asthma. Multi-symptom asthmatics were at greater risk of having indicators of severe asthma. In all adults, being raised on a farm was associated with a decreased risk of allergic sensitisation, rhinitis and eczema, but not asthma. However, among adolescents (ie, those 16 to 20 years of age), being raised on a farm decreased the risk of asthma. Personality traits were associated with both beliefs of asthma medication and adherence to treatment.

FUTURE PLANS

Follow-up of the cohort is being undertaken every 8 to 10 years. The repeated clinical examinations will take place in 2019 to 2022. The cohort data are currently being linked to routine Swedish healthcare registers for a continuous follow-up. Mechanistic, genomic, genetic and translational investigations are ongoing.