CRP and inflammatory response: These results matched with those of the studies conducted by Gan et al., Barnes et al., and Kazmierczak et al. who have shown, in addition to lung inflammation, that a state of chronic systemic inflammation was observed in COPD evidenced by increases in the serum levels of CRP, fibrinogen, serum amyloid A (SAA), and pro‐inflammatory cytokine including IL‐6 in COPD patients.