LAUSR

Introduction Acute exacerbations (AEs) increase morbidity and mortality of patients with chronic pulmonary diseases. Little is known about the characteristics and impact of AEs on children's interstitial lung disease (chILD). Methods The Kids Lung Register collected data on AEs, the clinical course and quality of life (patient-reported outcomes - PRO) of rare paediatric lung diseases. Characteristics of AEs were obtained. Results Data of 2822 AEs and 2887 register visits of 719 patients with chILD were recorded. AEs were characterised by increased levels of dyspnoea (74.1%), increased respiratory rate (58.6%) and increased oxygen demand (57.4%). Mostly, infections (94.4%) were suspected causing an AE. AEs between two register visits revealed a decline in predicted FEV1 (median −1.6%, IQR −8.0 to 3.9; p=0.001), predicted FVC (median −1.8%, IQR −7.5 to 3.9; p=0.004), chILD-specific questionnaire (median −1.3%, IQR −3.6 to 4.5; p=0.034) and the physical health summary score (median −3.1%, IQR −15.6 to 4.3; p=0.005) compared with no AEs in between visits. During the median observational period of 2.5 years (IQR 1.2–4.6), 81 patients died. For 49 of these patients (60.5%), mortality was associated with an AE. Conclusion This is the first comprehensive study analysing the characteristics and impact on the clinical course of AEs in chILD. AEs have a significant and deleterious effect on the clinical course and health-related quality of life in chILD.