Among children and adolescents with asthma, frequent exacerbations and high disease severity were associated with an increased risk of fixed airflow obstruction, according to study results published in Pediatric Pulmonology.
Outpatients with asthma between the ages of 6 and 18 years were enrolled in this prospective observational cohort study (n=358). Researchers examined several patient-specific variables and their association with fixed airflow obstruction, an expiratory airflow limitation that is not completely reversible. These variables included anthropometric data, asthma history, number of hospitalizations, frequent exacerbations, asthma severity, asthma control, inhaled corticosteroid dose, atopy, and lung function. Fixed airflow obstruction was defined as the ratio of the forced expiratory volume in the first second to the forced vital capacity below the lower limit of normal, irrespective of inhaled and oral corticosteroid treatment.
During the 4-year follow-up, patients were determined to have fixed airflow obstruction (n=34) or no fixed airflow obstruction (n=324). The ages in the fixed airflow obstruction and non-fixed airflow obstruction groups were 12.1±3.1 and 9.8±3.6 (P <.001), respectively. Factors associated with fixed airflow obstruction in the univariate analysis included age, body mass index, hospitalizations for asthma, bronchodilator response, frequent exacerbations, length of exacerbations, and asthma severity.
In the multiple logistic regression analysis, however, the only variables associated with fixed airflow obstruction were frequent exacerbations (risk relative [RR], 4.0; 95% CI, 1.3‐11.7; P =.002) and higher severity (Global Initiative for Asthma [GINA] steps 4-5; RR, 3.5; 95% CI, 1.6‐7.6; P <.001).
Study limitations included the small sample size of the fixed airflow obstruction population, as well as the reliance on parental report of patients’ asthma history.
Based on their findings, the researchers suggested that “[m]easures to prevent frequent exacerbations could help to avoid reduced lung functional capacity” among children and adolescents with asthma.
Sousa AW, Barros Cabral AL, Martins MA, Carvalho CRF. Risk factors for fixed airflow obstruction in children and adolescents with asthma: 4-Year follow-up [published online January 7, 2020]. Pediatr Pulmonol. doi:10.1002/ppul.24625