Cardiac surgery results in a multifactorial systemic inflammatory response with inflammatory
cytokines, such as
interleukin-10 and 6 (IL-10 and IL-6), shown to have potential in the prediction of adverse outcomes including readmission or mortality. This study sought to measure the association between
IL-6 and
IL-10 levels and 1-year
hospital readmission or mortality following cardiac surgery. Plasma
biomarkers IL-6 and
IL-10 were measured in 1,047 patients discharged alive after isolated
coronary artery bypass graft surgery from eight medical centers participating in the Northern New England
Cardiovascular Disease Study Group between 2004 and 2007. Readmission status and mortality were ascertained using Medicare, state all-payer claims, and the National Death Index. We evaluated the association between preoperative and postoperative
cytokines and 1-year readmission or mortality using Kaplan-Meier estimates and Cox's proportional hazards modeling, adjusting for covariates used in the Society of Thoracic Surgeons 30-day readmission model. The median follow-up time was 1 year. After adjustment, patients in the highest tertile of postoperative
IL-6 values had a significantly increased risk of readmission or death within 1 year (HR: 1.38; 95% CI: 1.03-1.85), and an increased risk of death within 1 year of discharge (HR: 4.88; 95% CI: 1.26-18.85) compared with patients in the lowest tertile. However, postoperative
IL-10 levels, although increasing through tertiles, were not found to be significantly associated independently with 1-year readmission or mortality (HR: 1.25; 95% CI: .93-1.69). Pro-inflammatory
cytokine IL-6 and anti-inflammatory
cytokine IL-10 may be postoperative markers of cardiac injury, and
IL-6, specifically, shows promise in predicting readmission and mortality following cardiac surgery.