C-reactive protein levels are raised in stable Chronic obstructive pulmonary disease patients independent of smoking behavior and biomass exposure

Background: The aim of this case control study is to assess the relationship between serum C-reactive protein (CRP) levels and well-known clinical parameters in Chronic obstructive pulmonary disease (COPD) considering the impact of smoking behavior, biomass exposure and accompanying clinical entities, namely pulmonary hypertension, systemic hypertension and diabetes mellitus. Methods: Spirometry, echocardiography, arterial oxygen saturation (SpO2) measurements, BODE scores and serum CRP levels were investigated in stable COPD patients. Associations between CRP levels and clinical parameters were evaluated. Results: CRP levels are significantly higher in COPD patients than in healthy controls. CRP levels were not significantly different between COPD patients treated with inhaled corticosteroids and those not treated. CRP levels significantly correlated with age, FEV1% predicted, FVC% predicted, SpO2, MMRC, 6 minute walk distance, BODE scores and haemoglobin levels. In multivariate analysis BODE scores and concomitant systemic hypertension manifested the strongest association with CRP levels. CRP levels in COPD patients with and without pulmonary hypertension were significantly different. CRP levels did not differ significantly according to smoking status or biomass exposure, moreover COPD cases due to biomass exposure who never smoked also had higher CRP levels compared to healthy controls. Conclusions: Systemic inflammation is inherent to COPD independent of ever-smoking status and correlates with disease severity, concomitant systemic hypertension and pulmonary hypertension.