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Three-year follow-up of Interleukin 6 and C-reactive protein in chronic obstructive pulmonary disease
Renata Ferrari1, Suzana E Tanni, Laura M O Caram
1Faculdade de Medicina de Botucatu, Univ Estadual Paulista, Unesp, Disciplina de Pneumologia, Botucatu, São Paulo, Brazil. renataferrarifisio@gmail.com
Insights
In COPD patients, Interleukin-6 (IL-6) levels significantly increased over three years, indicating persistent inflammation. This rise in IL-6 was linked to poorer walking distance and increased mortality risk.
Area of Science:
- Pulmonary Medicine
- Immunology
- Chronic Disease Management
Background:
- Previous studies indicated stable Interleukin-6 (IL-6) and C-reactive protein (CRP) levels in COPD patients over one year.
- Longitudinal studies evaluating inflammatory markers over extended periods in COPD are limited.
Purpose of the Study:
- To assess plasma CRP and IL-6 concentrations over a three-year period in patients with Chronic Obstructive Pulmonary Disease (COPD).
- To investigate the association between these inflammatory mediators and disease outcome markers, including mortality and physical performance.
Main Methods:
- A prospective study involving 53 stable COPD outpatients.
- Evaluation of IL-6, CRP, six-minute walking distance (6MWD), and body mass index (BMI) at baseline and after three years.
- High-sensitivity ELISA for IL-6 and particle-enhanced immunonephelometry for CRP.
Main Results:
- IL-6 levels significantly increased over three years (p < 0.001) and correlated with reduced 6MWD.
- Elevated baseline IL-6 was associated with increased mortality (HR=2.68, p=0.02).
- Mean CRP levels remained stable, though 21% of patients showed significant CRP changes.
Conclusions:
- Systemic inflammation, as indicated by IL-6, is persistent and progressive in COPD patients.
- Increased IL-6 is associated with worse physical performance and higher mortality risk in COPD.
Background:
Past studies have shown that mean values of Interleukin-6 (IL-6) and C-reactive protein (CRP) do not change significantly in COPD patients over a one-year period. However, longer period follow-up studies are still lacking. Thus, the aim of this study is to evaluate plasma CRP and IL-6 concentration over three years in COPD patients and to test the association between these inflammatory mediators and disease outcome markers.
Methods:
A cohort of 77 outpatients with stable COPD was evaluated at baseline, and 53 (mean FEV1, 56% predicted) were included in the prospective study. We evaluated Interleukin-6 (IL-6), C-reactive protein (CRP), six-minute walking distance (6MWD), and body mass index (BMI) at baseline and after three years. Plasma concentration of IL-6 was measured by high sensitivity ELISA, and CRP was obtained by high sensitivity particle-enhanced immunonephelometry.
Results:
IL-6 increased significantly after 3 years compared to baseline measurements [0.8 (0.5-1.3) vs 2.4 (1.3-4.4) pg/ml; p < 0.001] and was associated with worse 6MWD performance. In the Cox regression, increased IL-6 at baseline was associated with mortality [Hazard Ratio (95% CI) = 2.68 (0.13, 1.84); p = 0.02]. CRP mean values did not change [5 (1.6-7.9) vs 4.7 (1.7-10) pg/L; p = 0.84], although eleven patients (21%) presented with changes >3 mg/L in CRP after 3 years.
Conclusions:
The systemic inflammatory process, evaluated by IL-6, seems to be persistent, progressive and associated with mortality and worse physical performance in COPD patients.
Trial Registration:
No.:NCT00605540.
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