Background: Although inflammatory markers have an important role in Idiopathic pulmonary hypertension (IPAH), there is limited information about the relationship between inflammatory markers and pulmonary hypertension (PH) occurring secondary to COPD. Our aim was to investigate association of systemic inflammation reflected by circulatory levels of hs-CRP, IL-6 and TNF-α in COPD patient with and without PH.
Methods: The cross-sectional study recruited 68 patients with COPD age above 40 years. Lung function was assessed using spirometry; pulmonary artery pressure (Ppa) levels were measured by color Doppler echocardiography. Serum TNF-α and IL-6 levels were assessed by ELISA, and hs-CRP by Immunonephelometry.
Results: Serum hs-CRP and TNF- α levels were significantly higher in patients with PH compared to those without PH (p=0.034 & p=0.041 respectively). No differences were seen between the two groups in terms of serum IL-6 levels (p=0.0623). A significant linear relationship was observed between log-transformed hs-CRP level and mPAP in the whole group (r= 0.337; p =0.121) and between log-transformed TNF- α and mPAP in the whole group (r =0.413; p= 0.104). No significant relationships were observed between log-transformed IL-6 and mPAP. In multiple linear regression analysis, independent predictors of mPAP (R2=0.394) was log hs-CRP (p 0.013) and peripheral oxygen saturation (Spo2) (p 0.115). Log TNF- α was not an independent predictor of mPAP (p 0.823).
Conclusion: The study suggested that increases in Ppa in patients with COPD are associated with higher serum levels of hs-CRP and TNF-α, raising the possibility of systemic inflammation in the pathogenesis.