title: Systemic biomarkers in exacerbations of COPD: the evolving clinical challenge.
abstract: BACKGROUND
  Exacerbations of COPD (ECOPD) remain a major cause of mortality and morbidity. Despite advances in the understanding of their pathophysiology, their assessment relies primarily on clinical presentation, which can be variable and difficult to predict. A large number of biomarkers already have been assessed in this context, and some appear to be promising.
  
  
  METHODS
  An online search for articles published until December 2010 was conducted using three terms for ECOPD, five terms for biomarkers, and five terms for the sampling method. Biomarkers were evaluated for their potential role in the establishment and confirmation of the diagnosis of ECOPD, the evaluation of etiology and severity, the prediction of prognosis, and the guidance of treatment decisions.
  
  
  RESULTS
  Several systemic biomarkers have been measured in the context of ECOPD, and most have been found to increase at ECOPD onset and to subside during the course of exacerbations. Correlations have been reported among these biomarkers, but direct associations with clinical variables have been more difficult to establish. Although there are several limitations yet to be addressed, some of the biomarkers, most notably C-reactive protein for the identification of an ECOPD and procalcitonin for antibiotic guidance, may provide clinically relevant information.
  
  
  CONCLUSIONS
  So far, no single biomarker has been able to gain wide acceptance, but some provide clinically useful information. The evaluation of such biomarkers in large decision-making studies is expected to become an area of intense investigation in the near future.
authors.affiliation: Service de Pneumologie et Rehabilitation Respiratoire, Hôpital de Rolle, Switzerland.
authors.forename: Angela
authors.initials: A
authors.lastname: Koutsokera
authors.affiliation: Clinic for Pulmonary Medicine and Respiratory Cell Research, University Hospital, Basel, Switzerland.
authors.forename: Daiana
authors.initials: D
authors.lastname: Stolz
authors.affiliation: Second Respiratory Medicine Department, University of Athens Medical School, Athens, Greece.
authors.forename: Stelios
authors.initials: S
authors.lastname: Loukides
authors.affiliation: Second Respiratory Medicine Department, University of Athens Medical School, Athens, Greece. Electronic address: ktk@otenet.gr.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kostikas
mesh_terms: D015415:Biomarkers / Q000032:analysis*; D018450:Disease Progression; D006801:Humans; D011237:Predictive Value of Tests; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D012306:Risk; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers