CRP and chronic obstructive pulmonary disease: Participants with moderate airflow obstruction (defined as FEV 1 50%-80% of predicted) were 1.56 times more likely to have highly elevated serum CRP levels.[25] Regarding the group with COPD and cardiovascular complications in the present study, there is also a positive correlation between TNF-α and stage of COPD according to FEV1 in the COPD and cardiovascular complications group.