Association of reported symptoms and lung function among people with primary ciliary dyskinesia

<bold>Background:</bold> People with primary ciliary dyskinesia (PCD) present a variety of respiratory symptoms, however it is not known whether these are captured by commonly used objective measures, such as lung function tests. We aimed to study associations between respiratory symptoms and airway obstruction, assessed by spirometry. <bold>Methods:</bold> We sent the FOLLOW-PCD questionnaire to all patients ≥14 years and parents of children, registered in the Swiss PCD Registry, asking about upper and lower respiratory symptoms. In patients who had a routine lung function done within a year of survey completion, we used linear regression to study associations between FEV1 and frequency of respiratory symptoms, adjusted for age, sex, tobacco exposure, and regular physiotherapy. <bold>Results:</bold> 64 out of 99 invited (67%) completed the survey; of these 54 (median age 24 years, IQR 15-47; 50% females) had an FEV1 measurement (mean z-score - 2.09 [−5.24 to –2.03]), with 3 months median time between survey and visit. We found no signs of association between reported frequent nasal symptoms, headache, snoring, cough, sputum production, and chest pain with FEV1. Patients reporting frequent wheeze (28%) or shortness of breath (29%) had a lower FEV1 z-score (−0.31 [95%CI −0.59 to −0.03] and −0.61 [−0.95 to −0.26] respectively). Increasing age was a predictor of lower FEV1. <bold>Conclusion:</bold> In our study frequent wheeze and shortness of breath were associated with lower FEV1, commonly used for patient follow-up. However, we need additional outcome measures e.g. assessing lung volumes or upper airway problems, to capture the range of respiratory symptoms people with PCD experience in daily life. <bold>Funding:</bold> SNF PZ00P3_185923, BEAT-PCD