Risk factors for fixed airflow obstruction in children and adolescents with asthma: 4‐Year follow‐up

Abstract

Background Asthma is a disease with reversible bronchoconstriction; however, some patients develop fixed airflow obstruction (FAO). Previous studies have reported the incidence and risk factors of FAO in adults; however, the corresponding factors in children remain poorly understood. Aim To evaluate the incidence and risk factors of FAO in children and adolescents with asthma. Method Observational and prospective cohort study with a 4‐year follow‐up of clinically stable patients with asthma (from 6‐8 years old). Anthropometric data, history of asthma, number of hospitalizations, frequent exacerbations, asthma severity, asthma control, inhaled corticosteroid dose, atopy, and lung function were analyzed as potential risk factors for FAO. FAO was defined by a ratio of the forced expiratory volume in the first second to the forced vital capacity below the lower limit of normal, even after inhaled and oral corticosteroid treatment. Results Four hundred and twenty‐eight patients were recruited, and 358 were analyzed. The FAO incidence in children and adolescents with asthma was 9.5% (n = 34), starting at 10 years of age. Age, body mass index, hospitalizations for asthma, bronchodilator response, frequent exacerbations, length of exacerbations, and asthma severity were associated with FAO. Frequent exacerbations (odds ratio [OR] = 4.0; 95% confidence interval [CI] = 1.3‐11.7) and asthma severity categorized as steps 4 to 5 (OR = 3.5; 95% CI = 1.6‐7.6) remained risk factors. Conclusions Frequent exacerbations and asthma severity are the risk factors for FAO in children and adolescents with asthma.

Physical fitness and quality of life in adolescents with asthma and fixed airflow obstruction

“…Airflow obstruction can often be reversed either spontaneously or with pharmacological treatment (1). However, approximately 10% of infant subjects with asthma in a previous study exhibited an expiratory airflow limitation that was not completely reversible, despite optimal treatment being provided (2); this condition is known as fixed airflow obstruction (FAO) (3).…”

“…The development of FAO has been explained by a type of pathological airway remodeling that leads to structural changes in the airway and airflow restrictions (4). The risk factors for FAO are multifactorial and differ between adults and children (2,5). The main risk factors for FAO in adults include a subjects' sex, his or her smoking habits, the presence of rhinitis, atopy, and eosinophil inflammation; and the amount of fractional exhaled nitric oxide (5).…”

“…The main risk factors for FAO in adults include a subjects' sex, his or her smoking habits, the presence of rhinitis, atopy, and eosinophil inflammation; and the amount of fractional exhaled nitric oxide (5). In children and adolescents, the risk factors are related to asthma severity and the frequency of exacerbations (2).…”

“…Previous studies have reported that subjects with FAO exhibit higher asthma hospitalization rates and more severe symptoms such as dyspnea, wheezing, and chest tightness than do their non-FAO peers (2,4). The fear of feeling asthma symptoms could inhibit many subjects from taking part in regular physical activity due to exercise-induced bronchoconstriction (6).…”

Physical fitness and quality of life in adolescents with asthma and fixed airflow obstruction

“…4 The risk factors for FAO are multifactorial and differ between adults and children. 2,5 The main risk factors for FAO in adults include a subject's sex, smoking habits, the presence of rhinitis, atopy, and eosinophil inflammation, and the amount of fractional exhaled nitric oxide. 5 In children and adolescents, the risk factors are related to asthma severity and the frequency of exacerbations.…”