Summary
Background: Patients with Chronic Obstructive Pulmonary Disease (COPD) are at higher risk of
developing Community-Acquired Pneumonia (CAP) than patients in the general population.
However, no studies have been performed in general practice assessing longitudinal incidence
rates for CAP in COPD patients or risk factors for pneumonia onset.
Methods: A cohort of COPD patients aged 45 years, was identified in the General Research
Practice Database (GPRD) between 1996 and 2005, and annual and 10-year incidence rates of
CAP evaluated. A nested case-control analysis was performed, comparing descriptors in COPD
patients with and without CAP using conditional logistic regression generating odds ratios (OR)
and 95% confidence intervals (CI).
Results: The COPD cohort consisted of 40,414 adults. During the observation period, 3149
patients (8%) experienced CAP, producing an incidence rate of 22.4 (95% CI 21.7e23.2) per
1000 person years. 92% of patients with pneumonia diagnosis had suffered only one episode.
Multivariate modelling of pneumonia descriptors in COPD indicate that age over 65 years
was significantly associated with increased risk of CAP. Other independent risk factors