Interleukin-6 levels as an evolution marker of late mortality and cardiovascular events after an episode of community-acquired pneumonia.

Abstract

Introduction: The persistence of inflammation in community-acquired pneumonia (CAP) patients could lead to appearance of cardiovascular events and higher mortality. Parameters capable of quantifying this inadequate inflammatory response are promising prognosis biomarkers. This study analyzes the association between several biomarkers in a CAP episode and the incidence of major cardiovascular events and mortality during 1-year follow-up. Material and Methods: Prospective study of hospitalized CAP patients. Blood tests were performed at two points: admission and early-stage evolution (day 3-5 after admission). Several leukocyte parameters, immune markers and cytokines were analyzed in blood samples. The outcome variable was Major Adverse Cardiovascular Events (MACE) at one year (Mortality, Acute Myocardial Infarction or Stroke). Results: 151 hospitalized CAP patients were included. The differential biomarker values between the two determination points were associated with the appearance of MACE during the one year follow-up for copeptin, proadrenomedulin, neutrophil count percentage, lymphocyte count percentage, neutrophil / lymphocyte ratio and IL-6. After multivariate analysis, only the persistence of high levels of IL-6 between the two points is associated with higher cumulative risk of MACE, regardless of age, severity, cardiovascular risk scales and comorbidities. Conclusions: The evolution of IL-6 values between admission and early stage evolution is strongly related to higher risk of MACE during the post-episode year. The detection of this sustained inflammation during the infection could strengthen the prevention of long-term cardiovascular events.