Definitions of asthma exacerbationsLoymans, Rik JB; ter Riet, Gerben; Sterk, Peter JCurrent Opinion in Allergy & Clinical Immunology: June 2011 - Volume 11 - Issue 3 - p 181–186 doi: 10.1097/ACI.0b013e3283466f45 Outcome measures: Edited by Henry Milgrom and Ralph Mosges Abstract Author Information Purpose of review: During the past decade exacerbations of asthma have increasingly been recognized a as primary outcome parameter in clinical research. However, comparison of results is hampered by the use of different definitions for asthma exacerbations in published reports. The purpose of this review is to describe the consequences of using different definitions and to propose possible solutions. Recent findings: The use of different definitions of asthma exacerbations not only influences incidence rates, but also affects patient identification and risk assessment. The American Thoracic Society/European Respiratory Society and the World Health Organization independently proposed consensus definitions based on clinical symptoms and management. This needs to be complemented by a prospective definition that may support clinicians in their treatment decisions. Conclusion: Currently there is no commonly accepted definition for asthma exacerbations. A prospective definition is desirable. This could be obtained by phenotyping asthma exacerbations based on clinical signs, lung function parameters and possibly other biomarkers. aDepartment of General Practice, the Netherlands bDepartment of Respiratory Medicine, Academic Medical Centre - University of Amsterdam, Amsterdam, the Netherlands Correspondence to Loymans, Rik JB, MSc, MD, Department of General Practice, Academic Medical Centre – University of Amsterdam, P.O. Box 22700, 1100 DE Amsterdam, The Netherlands Tel: +31 205667774; e-mail: firstname.lastname@example.org Copyright © 2011 Wolters Kluwer Health, Inc. All rights reserved.