Abstract

Background and objectives: Exacerbations, systemic manifestations and comorbidities have a great impact on the morbidity and mortality of COPD. Our study aimed to evaluate the presence and the strength of a possible association between inflammatory biomarkers (especially CRP), the presence of CVD and muscular impairment in patients with stable COPD.
Materials and methods: We included 59 patients with stable COPD who were divided in two study cohorts: group A-27 COPD patients with normal levels of C-reactive protein (CRP) and group B-32 patients with increased levels of CRP at two measurements within 6 month. In group B were also analyzed Endothelin-1 (ET-1), Tumor Necrosis Factor Alpha (TNF-α) and Interleukin 6 (IL6). Both groups performed spirometry, 6 min walk distance test (6MWD), Maximal Expiratory Pressure (MEP) and Maximal Inspiratory Pressure (MIP), CAT (COPD Assessment Test), dynamometry, body composition, ECG, carotid ultrasound and echocardiography.
Results: Patients with persistent systemic inflammation when compared with normal CRP ones, had a higher age (64 yrs vs. 58 yrs, p=0.048), higher prevalence of CVD (3 vs. 1, p=0.005), dyslipidemia (61% vs. 39%, p=0.117), more pronounced upper extremity muscle weakness (dynamometry 4.5 vs. 5.5, p=0.048) and respiratory muscle weakness (MEP 50.3 vs. 57.3, p=0,038). They also had a slightly more limited exercise tolerance (6MWD 394.1 m vs. 430.6 m p=0.273), were slightly more symptomatic (CAT 21 pts vs. 16.5 points, p=0.141) and had a higher body mass index (26.5 kg/m² vs. 24.5 kg/m², p=0.187). Elderly patients had increased levels of CRP, TNF-α and IL-6.
Conclusion: In a context of stable COPD, persistently elevated CRP levels are associated with higher age, higher prevalence of CVD and more severe muscle weakness. Biomarkers like ET-1, TNF-α and IL6 do not reveal additional contributions in these systemic inflamed COPD group.

Keywords: Endothelin-1; CRP, Endothelium; Atherosclerosis; Muscular dysfunction; Stable COPD