Table 3 Eligibility criteria

Has a current acute exacerbation (presenting with at least 1 of the following: increased dyspnoea, increased sputum volume, increased sputum purulence) that has lasted for at least 24 h and no longer than 21 days

The responsible GP feels urgent referral to hospital is necessary

Diagnosis of COPD in clinical record/on COPD practice register

Severe illness (e.g. suspected pneumonia, tachypnoea > 30 breaths/min, respiratory failure)

Age 40 years or more

Concurrent infection at another site (e.g. UTI, cellulitis) that is likely to produce a systemic response

Able to provide informed consent

Past history of respiratory failure or mechanical ventilation

Patient should be able to provide the primary outcome data at 2 and 4 weeks within the expected windows

Currently taking antibiotics or has taken antibiotics for this acute exacerbation of COPD

Active inflammatory condition (e.g. flare up of rheumatoid arthritis, gout or polymyalgia rheumatica)

Has cystic fibrosis, a current tracheostomy or bronchiectasis

Immunocompromised (e.g. AIDS, taking systemic immunosuppressive therapy or receiving anti-cancer radiotherapy or chemotherapy)

Currently pregnant

Previously been recruited into the PACE study