Abstract Introduction Acute exacerbations (AE) of idiopathic pulmonary fibrosis (IPF) are unpredictable complications associated with high morbidity and mortality. Early identification could enable timely therapeutic intervention and potentially improve patient outcomes. This pilot study explored whether daily home-based spirometry permits earlier detection of AE-IPF. Methods We recruited 42 patients with confirmed IPF with a forced vital capacity FVC ≤ 70% predicted and/or diffusion capacity DLCO ≤ 60% across five German ILD centers within the German Center for Lung Research between December 2018 and October 2020. All participants received antifibrotic therapy and performed daily home spirometry following a standardized training for 12 months. On-site pulmonary function tests were repeated every three months. Home FVC data were cleaned for outliers and analyzed using linear mixed-effects models. Individual slopes were clustered via k-means into improving, stable, or worsening patterns. Occurrence and timing of AE-IPF (as defined by Collard et al., AJRCCM, 2016) were evaluated against FVC trajectories. Results A total of 12.059 spirometry measurements were analyzed. Participants were predominantly male (86%), with a mean age of 68 years and baseline FVC 62%. There was a good agreement between home and hospital FVC values in Bland-Altman analysis with a mean difference of -0.14 (95% CI: -0.24 to -0.04). A linear mixed effect model revealed a nonsignificant overall downward FVC trend (p = 0.051) in home spirometry but not in the formal testing. There was a notable interindividual variability: 24 patients displayed stable, 12 improving, and 6 worsening FVC slopes. Seven patients (16.7%) experienced an acute exacerbation during the study. A deterioration in FVC prior to an exacerbation was not observed, while in 5 patients, home spirometry demonstrated a FVC decline (mean ml) at or after the clinical onset of AE. One patient exhibited an FVC decrease up to three months before acute exacerbation. Conclusion Daily home-based spirometry is technically feasible and correlates well with conventional measures in IPF patients. While regular home spirometry can detect a decline in FVC during and after an acute exacerbation in IPF, it was unable to detect a meaningful decline in lung function before the clinical diagnosis of AE-IPF. Our results suggest, that daily home-based spirometry is not suitable for prediction or early detection of acute exacerbations in IPF. This abstract is funded by: German Center for Lung Research
Kroenig et al. (2026) studied this question.