Characterising adult Primary ciliary dyskinesia (PCD) in the EMBARC-BRIDGE cohort

PCD is an inherited cause of bronchiectasis. EMBARC-BRIDGE is a translational research substudy embedded within the European Bronchiectasis Registry. We compare patients with PCD in EMBARC BRIDGE to bronchiectasis of other causes. Adults with bronchiectasis were recruited to an observational cohort study from 19 centres across Europe from Dec 2019 – Jan 2025. PCD patients (n=76) were younger compared to bronchiectasis without PCD (n=1026) (42 vs 67yrs) p<0.0001. There was a female predominance in both groups 64% vs 61%. PCD patients had more upper airway disease: Nasal polyps 52.6% vs 6.8% and rhinosinusitis 78.9% vs 22.6%, p<0.0001. Compared to other patients with bronchiectasis PCD patients had a reduced FEV1% pred mean (StDEv) (66.2(23.9) vs 82(26.3)), more severe exacerbations in the previous year p=0.017 and more reported major haemoptosis (13% vs 6%) p=0.011. 72% PCD patients vs 27% non-PCD reported a positive bacterial culture for P. aeruginosa. Daily sputum volume was ̴double in PCD mean (St Dev) 44mls (43) vs 23(34). There was a high treatment burden in PCD with 93% compared to 71% taking regular respiratory treatments (p=0.0008). More PCD patients practiced daily chest physiotherapy 87% vs 58% p<0.0001. Quality of life was impaired in PCD in the QoL-B domains of treatment burden, physical and vitality. The two groups were similar in role, social and emotional functioning. 26% PCD patients reported previously participating in a bronchiectasis clinical trial compared to 3% of the rest of the cohort p<0.0001 In summary people with PCD are younger with more severe disease and high treatment burden compared to other patients with bronchiectasis.