Abstract
Background: In older adults, lung function impairment is a predictor of cardiovascular mortality, but the association between airflow obstruction and development of systemic inflammation has not been described in asthma patients.
Aim: To investigate whether lung function impairment in asthma leads to development of systemic inflammation, and to elucidate potential mechanistic links.
Methods: Asthma patients consecutively referred for specialist management were followed for 12 months. Lung function and markers of airway and systemic inflammation were measured at baseline and follow-up (Sputum: Neutrophils, IL-8, mRNA expression of TLR2 and TLR4. Blood: HS-CRP, IL-6, TNF-alfa, sCD163).
Results: A total of 96 asthma patients (Females: 57%, age: 28 years (15-63) were followed up. At baseline, the level of HS-CRP correlated with patient age (Spearmans rho: 0.29, p=0.002), BMI (0.37, p<0.001), triceps skin fold thickness (0.32, p= 0.001) and serum IL-6 (0.33, p= 0.001), but not FEV1%, sputum neutrophils, IL-8 or TLR 2 and TLR4.
HS-CRP at the 12-months follow-up correlated with the baseline FEV1% predicted (rho: -0.31, p= 0.009), independently of BMI, age, smoking status, as well as baseline HS-CRP and IL-6. Hence, patients with systemic inflammation at follow-up (HS-CRP > 3) were characterized by a significant decrement in lung function at baseline (FEV1%: 85.4 % (± 8.3) vs 100.0 % (± 17.6), p=0.012). At baseline, lower FEV1% was associated with higher airway neutrophils and TLR2 expression, but there was no association between these and HS-CRP at follow-up.
Conclusion: In adult asthma patients, lung function impairment is associated with an increased risk of subsequent development of systemic inflammation.
- Copyright ©ERS 2015