This longitudinal analysis of a large chronic obstructive pulmonary disease (COPD) study explored the identification of clusters and their behaviour over 2 years. We validated previous data on the topic but in a multicentre study and with 2 years of follow-up (previously only 1 year). We also identified factors associated with cluster changes.

Although non-invasive ventilation (NIV) is an established treatment for acute hypercapnic COPD, the optimal model of care is not known. We undertook a comparison of NIV delivery in general, high dependency and intensive care wards and identified equal efficacy, with considerable financial savings using the general ward model.

We evaluated 4 m gait speed (4MGS), a simple functional performance test, in people with stable idiopathic pulmonary fibrosis. We found 4MGS a reliable, valid and responsive measure that can detect a patient phenotype with worse dyspnoea, exercise performance, quality of life and prognostic risk.

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Multiple breath nitrogen washout (MBNW) or impulse oscillometry system (IOS) abnormalities were highly prevalent in smokers without COPD but highly discordant between individuals. Cough was related to peripheral conductive airway function, while wheeze was related to IOS and spirometry. In smokers with normal spirometry, MBNW and IOS abnormalities may have different underlying structural bases and prognostic significance.

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We evaluated prognostic significance of pneumothorax and the risk factors for its onset in patients with idiopathic pulmonary fibrosis (IPF). We demonstrate that the onset of pneumothorax predicts a poor outcome in the patients with IPF. Lower BMI and the presence of extensive reticular abnormalities are associated with developing pneumothorax.