CRP and chronic obstructive pulmonary disease: However, the COPD population was very heterogeneous: 27.3% of COPD patients had CRP levels > 10 mg/L, which is a significantly higher proportion than in healthy smokers (5.2%), whereas about 40% of COPD patents had no evidence of systemic inflammation as assessed by CRP levels alone (< 3 mg/L) or by the number of inflammatory markers in their top quartiles (no markers in the top quartile).