Airway and systemic inflammation and decline in lung function in patients with COPD

ABSTRACT

Study objective: Patients with COPD experience lower airway and systemic inflammation, and an accelerated decline in FEV. There is no evidence on whether this inflammation changes over time, or if it is associated with a faster decline FEV. Patient and design: a cohort of 148 COPD patients (100 men) was monitored daily for a median 2.9 years (interquartile range [IQR], 2.1 to 4.8). At recruitment median age was 68.5 years (IQR, 62.5 to 73.6) and FEV as percentage of predicted (FEV percent Pred) was 38.5 percent (IQR, 27.7 to 50.3). Results: During the study, the patients experienced 1,389 exacerbations, a median of 2.52/yr (IQR 1.48 to 3.96) and FEV declined by 40.2 mL/yr or as FEV percent Pred by 1.5 percent/yr. Concerning inflammatory markers, sputum interlukin (IL)-6 rose by 9 pg/mL, sputum neutrophil count rose by 1.64 x 10,000,000 cells per gram sputum per year, and plasma fibrinogen rose by 0.10 g/L/yr (all p, 0.05). Patients with frequent exacerbations (less than or equal to 2.52/yr) had a faster rise over time in plasma fibrinogen and sputum IL-6 of 0.063 g/L/yr (p= 0.046, n= 130) and 29.5 pg/mL/yr (p< 0.001, n=98), respectively, compared to patients with infrequent exacerbations (<2.52/yr). Using the earliest stable (nonexacerbation) measured marker, patients whose IL-6 exceeded the group median had a faster FEV percentPred decline of 0.97 percent/yr (p=0.001 and .40 percent/yr (p=0.014). respectively. Conclusions: In COPD, airway and systemic inflammatory markers increase over time; high levels of these markers are associated with a faster decline in lung function (AU)