Impact and prevalence of alpha-1 antitrypsin deficiency in different lung diseases

<bold>Introduction:</bold> Alpha-1 antitrypsin deficiency (AATD) may be related to worse outcomes in chronic obstructive pulmonary disease (COPD). However, the clinical impact in other lung diseases are unknown. The objectives were: determine the prevalence of genetic variants of AAT in distinct lung diseases and their impact on severe respiratory exacerbations <bold>Materials and Methods:</bold> Prospective observational study of AATD, by systematic consecutive sampling of patients who performed a lung function test from 12/2021 to 11/2023. A gingival mucosa swab test was used to determine AATD. Clinical, radiologic and lung function data were collected. Severe respiratory exacerbations were considered when requiring hospital admission <bold>Results:</bold> Of 544 patients enrolled, 51% were female and had 60.3 years (SD 15.3), 37% had COPD, 28% emphysema, 19% bronchiectasis, 14% asthma, 12% interstitial lung disease (ILD) and 24% had no lung disease. In 147 patients (27%) AATD was detected. 31% of mutations were family studies. In multivariate analysis, having an AAT mutation didn’t increase the risk of hospital admission, regardless of the respiratory disease. However, in univariate analysis, in ILD patients, the risk was increased by 29.8 (95%CI 4.0 to 219.5;p<0.001) <bold>Conclusions:</bold> In our series, around 25% of patients with lung diseases exhibited AATD, which didn't increase the risk of severe respiratory exacerbations. Further research should be assessed in selected groups <fig><object-id>erj;64/suppl_68/PA367/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig>