Virchow, J Christian2; Backer, Vibeke1; de Blay, Frédéric2; Kuna, Piotr2; Ljørring, Christian2; Prieto, Jesus L2; Villesen, Hanne H2
1 Lungemedicinsk Afdeling L, Bispebjerg and Frederiksberg Hospital, The Capital Region of Denmark2 unknown
BACKGROUND: Exacerbations are a key outcome in clinical research, providing patient-relevant information about symptomatic control, health state and disease progression. Generally considered as an episode of (sub)acute deterioration of respiratory symptoms, a precise, clinically useful definition is needed for use in clinical trials. AIM AND METHODS: Focussing on moderate exacerbations, this opinion piece reviews landmark trials and current guidelines to provide a practical definition of a moderate exacerbation. Specifically, we adapt the ATS/ERS consensus statement of terminology Reddel et al. (2009)  which provides a conceptual (or 'theoretical') definition for moderate exacerbations, to an operational (or 'practical') criterion suitable for use in clinical research. RESULTS: The proposed definition for a moderate exacerbation requires ≥1 of the following criteria combined with a change in treatment: a) nocturnal awakening(s) due to asthma requiring SABA for 2 consecutive nights or an increase of ≥0.75 from baseline in daily symptom scores on 2 consecutive days; b) increase from baseline in occasions of SABA use on 2 consecutive days (minimum increase: 4 puffs/day); c) ≥20% decrease in PEF from baseline on at least 2 consecutive mornings/evenings or ≥20% decrease in FEV1 from baseline and/or d) visit to the emergency room/trial site for asthma treatment not requiring systemic corticosteroids. CONCLUSION: A clinically and patient-relevant, operational definition of moderate exacerbations is needed. The proposed definition has been endorsed by the EMA Scientific Advice Working Party in 2011and needs to be trialled in forthcoming clinical studies.