The First International Conference on Exacerbations of Airways Disease (ICEAD) brought together experts from both sides of the Atlantic to discuss problems in the management of exacerbations of both asthma and chronic obstructive pulmonary disease (COPD). A brief overview of these discussions on COPD exacerbations follows.

DEFINITIONS AND EPIDEMIOLOGY

Symptom and treatment based definitions

Up to 18 definitions of a COPD exacerbation have been advanced, from less explicit1 to very explicit symptom based criteria.2 3 However, large therapeutic trials in COPD have all used treatment based definitions.4 5 The first consensus definition was treatment based but the current GOLD guidelines accept a symptom based definition.6 7 Biochemical or physiological markers applied in studies using either definition8 9 have all shown significant changes, supporting the validity of these approaches to a definition but lack specificity and sensitivity. The healthcare utilisation approach to severity of exacerbation may be more robust as it has been related to mortality10 but does not allow for detection of untreated exacerbations, which may contribute to poor quality of life.

Health burden

COPD patients have about 0.5–3.5 exacerbations/year, 0.09–2.4 hospitalisations/year and inhospital mortality varies between 10% and 60%, depending on the severity of COPD. Overall, the death rate varies from 5.4 per 1000 person years among normal subjects to 42.9 among subjects with GOLD stage 3 or 4.11 Thus COPD exacerbations are a significant cause of death, mainly in patients with more severe COPD. This leads to a high cost of COPD care which can be effectively reduced through decreasing hospitalisation.12

AETIOLOGY AND SUSCEPTIBILITY

Airway bacterial infection

Bacteria may be detected in up to 60% of exacerbations and viruses in 23–60%.13 14 A study of hospitalised patients found bacteria in 25%, bacteria and viruses in 25% and viruses alone in 25%, and no infectious agent in another 25%.14 The acquisition of new strains of bacteria …