Search for biomarkers in chronic obstructive pulmonary disease: current status

Purpose of review Chronic obstructive pulmonary disease (COPD) is a condition principally defined by airflow limitation that is not fully reversible. The main trigger, inhalation of noxious gases or particles (usually smoke) leads to complex pathology, including inflammation of the large and small airways, and destruction of the lung parenchyma. Overlap in pathophysiology with other chronic airways diseases leads to challenges in differential diagnosis, and furthermore, periodic exacerbations of disease symptoms also increase the complexity of the disease diagnosis and prediction of outcome. There is recognized need for biomarkers to aid in the determination of disease diagnosis, progression and response to intervention. This review describes the current status of biomarker identification in COPD. Recent findings Biomarkers of disease can take many forms other than the classical protein in serum, and their utility is dependent upon the clinical question to be addressed. No single protein marker has been adopted for routine clinical use to date. This review addresses the key issues around biomarker identification and utility in both stable and exacerbating COPD. Summary Biomarker identification in COPD is still a developing field, with increasing interest in patient phenotyping probably reflecting the challenges of biomarker development in a complex disease.