Inflammatory biomarkers in sputum predict COPD exacerbations

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.

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.

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.

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.