Background: Chronic airway diseases (CAD), including chronic obstructive pulmonary disease (COPD), asthma and bronchiectasis, are highly prevalent and cause serious disease burden. Multimorbidity is recognized to influence treatment decision and prognosis of patients with stable CAD. The impact of multimorbidity on exacerbation CAD is under investigated.

Methods: The Chronic Airway Disease and Multimorbidity (CAM) cohort study is a prospective, multicenter, observational study aiming to recruit a minimum of 2000 patients hospitalized for exacerbation of COPD, asthma or bronchiectasis. Comprehensive data, including demographics, medical history, comorbidities, lung function, echocardiography, microbiological profiles, radiology, quality of life and treatment will be collected at baseline during the hospitalization. Follow-up data indicating the impact of both CAD and multimorbidity will be collected at 1-, 3-, 6-, 9- and 12-months after hospital discharge. Biospecimens, including blood and bronchoalveolar lavage fluid, will be collected and analyzed for biomarker detecting. Primary outcome are length of hospital stay and re-exacerbation during fellow-up. Secondary outcomes include comorbidity pattern and its impact on respiratory symptoms burden, quality of life, pulmonary function and chest imaging as well as cost and healthcare utilization.

Conclusions: The knowledge generated from CAM cohort study will fill crucial gaps in understanding how multimorbidity affects CAD and facilitate evidence-based clinical practice in the future.