Lung Function Recovery from Pulmonary Exacerbations Treated with Oral Antibiotics in Primary Ciliary Dyskinesia.

Rationale: Patients with Primary Ciliary Dyskinesia (PCD) experience acute pulmonary exacerbations (PEx). In Cystic Fibrosis (CF), PEx treated with oral antibiotics (oPEx) were found to be related to short and long-term lung function deficits, however the impact oPEx on lung function in patients with PCD has not yet been assessed.

Objective: To assess the impact of oPEx on lung function recovery in PCD and determine the factors associated with poorer response.

Methods: This was a retrospective study of pediatric patients with PCD followed between 2000 to 2022 at SickKids (Toronto, Canada). PEx were defined as an increase in baseline symptoms with a physician decision to treat with systemic (intravenous (IV) or oral antibiotics. Lung function recovery was defined as a forced expiratory volume in 1 second (FEV1) measurement ≥90% of a stable baseline within 12 months before the PEx. Univariate and multivariate analyses were completed to identify risk factors for nonresponse.

Results: 337 PEx events in 85 patients were included in this analysis, of which 297 (88%) were treated with oral antibiotics. The mean (SD) follow up time for patients was 6.7 years (3.5) and the mean age of oPEx was 12.5 years (3.2). Patients with oPEx had a significant drop from baseline in mean FEV1 values at time of PEx (85.1% to 69.5%) with absolute and relative changes of -10.4% and -12.9%, respectively. At follow up (3 months post PEx) and up to 12 months post PEx, the mean FEV1 was 79.6% and 84.1%, respectively. 73.2% of the patients had lung function recovery at follow up visit which increased to 84.2% within one year post event. We identified two risk factors for nonresponse: being a non responder on the last PEx and younger age at time of oPEx. Conclusions oPEx in PCD show a similar pattern previously seen in CF patients with a decrease in FEV1 during exacerbation and an improvement post therapy. Most oPEx events recover to baseline FEV1 within the year post-exacerbation, with younger age and being non responder in the last PEx identified as risk factors for nonresponse.