To characterise and understand the current UK COPD population including demographics, active comorbidities and missed opportunities for COPD diagnosis in the years previous to diagnosis

Using real-world primary care clinical databases, ascertain whether 1) trends in respiratory resource utilisation prior to COPD diagnosis (including lower respiratory tract infections [LRTIs], consultations and hospitalisations) could be used as 'flags' to aid earlier diagnosis, and 2) characterize comorbid conditions present at the time of COPD diagnosis, and evaluate the relationship to COPD disease severity and age at diagnosis.

Inclusion Criteria:

• Aged 40 years or older
• Electronically coded diagnosis of COPD made between 1990 and 2009
• A minimum of three years continuous practice data including two years prior to and one year post diagnosis to ensure patients recieved COPD therapy post diagnosis
• Recieved two or more prescriptions for COPD therapies in the 12 months post diagnosis year 1.

Exclusion Criteria:

• Aged less than 40 years
• No diagnosis of COPD between 1990 and 2009
• Less than three years continuous practice data including two years prior to and one year post diagnosis
• Less than two prescriptions for COPD therapies in the 12 months post diagnosis year 1.

Subjects aged 40 years or older, with an electronically coded diagnosis of COPD made between 1990 and 2009, a minimum of three years continuous practice data including two years prior to and one year post diagnosis to ensure patients recieved COPD therapy post diagnosis (defined as two or more prescriptions for COPD therapies in the 12 months post diagnosis year 1). COPD therapies included short- and long-acting bronchodilators, inhaled corticosteroids, theophylline and leukotriene receptor antagonists.