In our study, patients with HI had more exacerbations in the year prior to the study as compared to patients colonized with PA. Both in COPD and bronchiectasis patients, HIis related to an increase in inflammation with higher levels of IL-6, IL-8, IL-1β and MPO and is an independent predictor for future exacerbations [27, 28]. Here, IL1B is linked to chronic obstructive pulmonary disease.