Nine-Year Follow-Up of Interleukin 6 in Chronic Obstructive Pulmonary Disease – Complementary Results from Previous Studies

Abstract

Robson Prudente,1 Renata Ferrari,2 Carolina Mesquita,2 Luiz Machado,2 Estefânia Franco,1 Irma Godoy,2 Suzana Tanni2 1Clinical Hospital of Botucatu Medical School, Department of Internal Medicine, Pneumology Area, Botucatu School of Medicine, São Paulo State University (UNESP), Botucatu, São Paulo, Brazil; 2Department of Internal Medicine, Pneumology Area, Botucatu School of Medicine, São Paulo State University (UNESP), Botucatu, São Paulo, BrazilCorrespondence: Robson PrudenteClinical Hospital of Botucatu Medical School, Department of Internal Medicine, Pneumology Area, Botucatu School of Medicine, São Paulo State University (UNESP), Botucatu, São Paulo, BrazilEmail [email protected]: Systemic manifestations of chronic obstructive pulmonary disease (COPD) are related to increased systemic inflammatory process; however, it is not entirely clear how much they are related and how the systemic inflammation, in particular interleukin-6 (IL-6), is associated with exacerbation and mortality risk.Objective: To evaluate the role of IL-6 in COPD patients over nine years.Study Design and Methods: A total of 133 COPD patients were assessed at baseline between 2004 and 2006 and reassessed after three and nine years through clinical evaluation, comorbidities, hematological blood count and IL-6 analysis.Results: After nine years, 19 patients lost the follow-up and were not possible to identify the date of death of four patients; 12 refused to participate and 1 could not be involved due to recurrent exacerbations. Therefore, 33 patients were included in the reassessment after nine years of follow-up and 92 patients were included in the Cox mortality analysis with IL-6 as a time-dependent covariate. Regarding the inflammatory profile, in patients who survived after nine years, there was a significant increase in IL-6 [0.4 (0.2– 0.8) vs 5.7 (3.4– 11) pg/mL; p < 0.001] and reduction in lymphocyte count [2.1 (1.6– 2.4) vs 1.4 (1.2– 2.1)10^9/L; p < 0.01] with an increase in the neutrophil/lymphocyte ratio (2.0 ± 0.7 vs 2.7 ± 1.2; p = 0.003). The Cox mortality model did not show a statistical significance influence of IL-6 assessed during the follow-up.Conclusion: There was a progressive increase in IL-6 during the follow-up, however, without influence on mortality.Keywords: chronic obstructive pulmonary disease, inflammation, interleukin-6, severity of illness index, mortality

Keywords

• chronic obstructive pulmonary disease. inflammation. interleukin-6. severity of illness index. mortality