Primary Ciliary Dyskinesia and Kartagener Syndrome as the Etiology of Adult Bronchiectasis: Independent Predictors from the German Bronchiectasis Registry PROGNOSIS

Background Primary Ciliary Dykinesia (PCD) is a rare genetic disorder, which regularly causes bronchiectasis with disease progression. Its prevalence as an etiology among adults with bronchiectasis is unknown. Diagnostic procedures for PCD are complex and not readily available in Germany. Thus, guidance is required with regard to referral for further diagnostic evaluation. Methods We investigated the prevalence of PCD/Kartagener syndrome (KS) within PROGNOSIS and identified independent clinical predictors using multivariate logistic regression analysis. All potential predictor or confounder variables of interest were entered simultaneously and model building was performed backward to calculate adjusted Odds ratios (aOR) and 95% confidence intervals (CI). The diagnosis of PCD/KS was historically and had been ascertained utilizing the whole spectrum of available diagnostic tests. Results Between Jun 2015 and Sep 2018, 1155 adult subjects with CT-confirmed bronchiectasis were recruited from 38 centers across Germany and across all levels of healthcare (15 private practices, 13 community and teaching hospitals, 10 university hospitals). Here, data from 1000 validated datasets are shown (mean age (SD) 59 (16) years; 59% female). Overall, the most common etiologies were idiopathic (n = 357; 36%), postinfectious/post-TB (n = 212; 21%), COPD (n = 149; 15%), and Asthma (n = 111; 11%), followed by PCD/KS (n = 88; 8.8%). Among those, KS was present in 18/88 subjects (21%). When ignoring situs inversus the following independent clinical features predicted PCD/KS: any upper airway involvement (aOR 5.9, 95%CI 3.33 – 10.47); known bronchiectasis for > 15 years (aOR 3.9, 95%CI 2.24 – 6.85); age < 57 years (aOR 3.3, 95%CI 1.75 – 6.19); radiological involvement of any middle and any lower lobe (aOR 2.8, 95%CI 1.36 – 5.67); chronic Pseudomonas aeruginosa infection (aOR 2.7, 95%CI 1.42 – 5.19); never smoker status (aOR 2.4, 95%CI 1.32 – 4.53); and absence of acquired cardiovascular comorbidity (aOR 2.0, 95%CI 1.02 – 4.07). Conclusions Within a representative cohort of adult German bronchiectasis patients basic clinical data could be identified to support the diagnosis of PCD/KS. Although further diagnostic confirmation is always required, this easy to achieve information may facilitate earlier diagnosis of PCD/KS.