Fetuin-A is associated with disease severity and exacerbation frequency in patients with COPD.

Fetuin-A is a liver protein that may serve as an inhibitor of systemic inflammation in humans. In the present study we assessed the levels of fetuin-A in COPD patients in stable condition and on exacerbation in an attempt to evaluate it as a clinically relevant biomarker that may serve as predictor of exacerbations of COPD (ECOPD). One hundred COPD outpatients (GOLD stage I to IV) were enrolled in a tertiary University hospital and were submitted to a detailed evaluation, including pulmonary function testing, exercise capacity, quality of life and evaluation of the presence of metabolic syndrome and serum CRP. All patients were followed-up for 1 year, and 36 were re-evaluated at the onset of an ECOPD. Forty otherwise healthy smokers served as controls. Serum fetuin-A levels were reproducible at baseline, 6 and 12 months. COPD patients presented lower levels of fetuin compared to controls [394.5 (321.8-419.6) vs. 487.3 (441.0-548.0) mg/L, p < 0.001]. COPD patients with GOLD stage IV had lower fetuin-A levels compared to stages I-II and III (p < 0.05). Fetuin-A was significantly reduced at the onset of an ECOPD compared to baseline (p < 0.001) and the time to the first ECOPD significantly different between patients with high and low levels of fetuin-A [HR 2.163 (95%CI 1.104-4.238), p = 0.024). The results of the present study suggest that fetuin-A is a reproducible and clinically relevant biomarker in patients with COPD that may be useful in the identification of exacerbation-prone patients.