Alpha-1 antitrypsin deficiency in patients with bronchiectasis: data from the European Bronchiectasis Registry EMBARC

Introduction: Alpha-1 antitrypsin deficiency is a recognised cause of bronchiectasis. There are few large cohorts, however, describing the frequency, clinical characteristics and severity of disease in this population. Methods: The European Bronchiectasis Registry (EMBARC) was studied from Jan 2015 to June 2019. Severity of disease was evaluated using the Bronchiectasis severity index (BSI) and quality of life using the QOL-B questionnaire. Results: Of 13512 patients included in the analysis, 3390 patients were tested for alpha-1 antitrypsin deficiency. Rates of testing by country varied from 0% in several countries to 67.5% in Portugal (UK 12.8%, Germany 40.2%, Italy 28.3%, Spain 43.8%) . Alpha-1 deficiency was identified in 77 patients (2.3%). Mean age was 61 years (SD 12), 47 females (61.0%). The mean bronchiectasis severity index was 7.8 points (SD 5.2). 26, 20 and 31 patients were classified as mild, moderate and severe respectively. The median exacerbation rate was 2 per year (range 0-13). Mean FEV1 was 70.2% (SD 32). Patients had moderate symptomatic impairment (mean QOL-B symptom score 58.7 SD 23). The most common organisms were Pseudomonas aeruginosa (23.4%), Enterobacteriales (9.1%), Staphylococcus aureus (9.1%), Haemophilus influenzae (6.5%) and NTM (5.2%). During follow-up (mean 3 years) patients with alpha-1 antitrypsin deficiency had a similar rate of exacerbations as patients with idiopathic bronchiectasis- rate ratio 1.12 95% CI 0.80-1.58,p=0.51. Conclusions: Alpha-1 antitrypsin deficiency is an uncommon cause of bronchiectasis in the EMBARC registry, but estimates are limited by infrequent testing. A study to determine the true prevalence of alpha-1 antitrypsin deficiency through systematic testing is needed.