1. Definitions of Exacerbations
Tanja W. Effing, PhD, Huib A.M. Kerstjens, MD, PhD, Evelyn M. Monninkhof, PhD, Paul D.L.P.M. van der Valk, MD, PhD, Emiel F.M. Wouters, MD, PhD, Dirkje S. Postma, MD, PhD, Gerhard A. Zielhuis, PhD, Job van der Palen, PhD 
CHEST 
Volume 136, Issue 3, Pages (September 2009)
DOI: /chest
Copyright © 2009 The American College of Chest Physicians Terms and Conditions

2. Figure 1
Flow chart of the search strategy. Of the included articles, the context in which the variable “exacerbation” was used is specified, and it is noted whether a definition of an exacerbation was defined.
CHEST  , DOI: ( /chest )
Copyright © 2009 The American College of Chest Physicians Terms and Conditions