Work

Preserved ratio impaired spirometry, dysanapsis and airflow obstruction with low forced expiratory volume in 1 s in childhood asthma

Year: 2025

Type: article

Abstract: Background Airway obstruction is a characteristic spirometric finding in asthma but the clinical significance of other abnormal spirometric patterns is less well described. We aimed to explore pre- and post-bronchodilator (BD) prevalences and clinical characteristics of preserved ratio impaired spirometry (PRISm), dysanapsis and airflow obstruction with low forced expiratory volume in 1 s (FEV 1 ) in children diagnosed with asthma. Methods We extracted specialist care data (clinical and spirometry) from the Swedish National Airway Register (n=3301, age 5–17 years). Normal spirometry was defined as FEV 1 ≥ lower limit of normal (LLN) and FEV 1 /forced vital capacity (FVC)≥LLN. PRISm was defined as forced FEV 1 < LLN and FEV 1 /FVC≥LLN, dysanapsis as FEV 1 /FVC 1 ≥LLN, and airflow obstruction with reduced FEV 1 as FEV 1 /FVC 1 10% were considered positive (BDRpos). Groups were compared using parametric tests and associations were explored using logistic regression analysis. Results Pre-/post-BD PRISm, dysanapsis and obstruction with low FEV 1 were identified in 9%/7%, 10%/4% and 8%/2%, respectively. Compared with normal spirometry, all three groups were associated with older age and BDRpos in pre-BD analyses. Furthermore, dysanapsis was associated with overweight/obesity and obstruction with low FEV 1 with uncontrolled asthma and more treatment. Interpretation In this paediatric asthma cohort, PRISm and dysanapsis were associated with BDRpos and they were at least as common as airflow obstruction with reduced FEV 1 . These spirometric phenotypes should be addressed in the management of childhood asthma and testing of BDR should be considered also in children with PRISm and dysanapsis.

Source: ERJ Open Research

DOI: 10.1183/23120541.00023-2025