Inflammatory Biomarkers in Sputum Predict COPD Exacerbations

Introduction: Exacerbations in chronic obstructive pulmonary disease (COPD) reduce quality of life and are associated with a more rapid deterioration of the disease. It is desirable to predict an oncoming exacerbation before it occurs. The aim of the present study was to identify biomarkers that may predict a forthcoming exacerbation.

Materials And Methods: Forty-three patients with COPD in their stable state were included and followed up monthly until exacerbation, or for a maximum of 6 months. The patients come for an extra visit (prior to a scheduled visit) when exacerbated. The patients completed the questionnaires CCQ and MRC. Exhaled breath condensate (EBC) was collected followed by spirometry, impulse oscillometry, and sputum induction.

Results: Twenty-five patients had an exacerbation within the 6-month period. Leukotriene B4 in sputum was the only biomarker that was increased at the visit prior to exacerbation compared to at the stable phase (p = 0.05). There also was a tendency for a similar but not significant increase in the sputum levels of 8-isoprostane, myeloperoxidase activity, and interleukin-8, as well as additional increases during exacerbation. Sputum purulence was not increased until exacerbation (p = 0.02). In contrast, none of the inflammatory biomarkers in EBC, the quality-of-life questionnaire score, CRP, spirometric parameters, or impulse oscillometry parameters were increased at the visit prior to exacerbation compared to the values at the stable phase.

Conclusion: Sputum biomarkers, especially leukotriene B4, could be used as predictors of a forthcoming exacerbation and worsening of COPD. This would be of great value for the patient, who may be a subject for early treatment and thereby avoid a progression of the disease.