Circulating surfactant protein D as a potential lung-specific biomarker of health outcomes in COPD: a pilot study

• Published in: BMC pulmonary medicine Vol. 7; no. 1; p. 13
• Main Authors: Sin, Don D, Leung, Rochelle, Gan, Wen Q, Man, Sf Paul
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 08.10.2007; BioMed Central; BMC
• Subjects: Aged; Biological markers; Biomarkers - blood; C-Reactive Protein - metabolism; Care and treatment; Chemical properties; Development and progression; Diagnosis; Disease Progression; Female; Forced Expiratory Volume; Health aspects; Health Status; Humans; Lung diseases, Obstructive; Male; Middle Aged; Patient outcomes; Physiological aspects; Pilot Projects; Pulmonary Disease, Chronic Obstructive - blood; Pulmonary Disease, Chronic Obstructive - physiopathology; Pulmonary surfactant; Pulmonary Surfactant-Associated Protein D - blood; Uteroglobin - blood; Vital Capacity; Canada
• ISSN: 1471-2466; 1471-2466
• DOI: 10.1186/1471-2466-7-13

There is a paucity of surrogate lung-specific biological markers that can be used to track disease progression and predict clinical outcomes in chronic obstructive pulmonary disease (COPD). The principal aim of this pilot study was to determine whether circulating surfactant protein D (SPD) or Clara Cell protein-16 (CC16) levels are associated with lung function or health status in patients with severe COPD. We studied 23 patients with advanced COPD. Lung function measurements, Chronic Respiratory Disease Questionnaire (CRQ) scores, and serum levels of SPD, CC16, and C-reactive protein (CRP) were determined at baseline and at 3 months. At baseline, FEV(1) was inversely associated with serum SPD levels (P = 0.045) but not with CC16 (P = 0.675) or CRP levels (P = 0.549). Over a 3 month period, changes in SPD levels correlated significantly with changes in CRQ scores (adjusted P = 0.008) such that patients who had the largest declines in serum SPD levels experienced the largest gains in health status. The association was particularly notable between circulating SPD level and the dyspnea domain of the CRQ score (P = 0.018). Changes in CC16 or CRP levels did not correlate with changes in CRQ scores. Changes in serum SPD levels tracked well with changes in health status over a 3 month period in patients with severe COPD. These data suggest that circulating SPD levels may be useful biomarkers to track health outcomes of COPD patients.