Early Plasma Interleukin-6 and Tumor Necrosis Factor-α Concentrations in Relation to Neurological Outcome After Cardiac Arrest: A Prospective Observational Cohort Study

Background and Objectives: The prognostic relevance of early post-resuscitation interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) remains uncertain. We evaluated their associations with discharge neurological outcome and combined discrimination. Materials and Methods: This prospective cohort study included adults achieving sustained return of spontaneous circulation (ROSC) after non-traumatic cardiac arrest. Plasma IL-6 and TNF-α were measured early after ROSC. Favorable neurological outcome was defined as Cerebral Performance Category 1–2 at hospital discharge. Analyses included receiver operating characteristic (ROC) curves and Firth regression adjusted for age, arrest location, and shockable initial rhythm. Results: Among 56 patients, 13 (23.2%) had favorable outcomes. The median ROSC-to-blood sampling interval was 29 min in both groups (p = 0.586). IL-6 concentrations were lower in patients with favorable than unfavorable outcomes (33.8 [15.9–52.6] vs. 66.2 [35.5–157.6] pg/mL), as were TNF-α concentrations (11.6 [4.9–15.3] vs. 27.6 [11.3–71.4] pg/mL; Holm-adjusted p = 0.034 for both). Areas under the ROC curves were 0.717 (95% confidence interval [CI], 0.541–0.867) for IL-6, 0.721 (0.552–0.862) for TNF-α, and 0.723 (0.553–0.865) for their combination, without significant pairwise differences. After adjustment, neither IL-6 (odds ratio per two-fold increase, 0.85; 95% CI, 0.49–1.53; p = 0.561) nor TNF-α (0.71; 95% CI, 0.43–1.11; p = 0.129) was independently associated with outcome. Conclusions: Early IL-6 and TNF-α concentrations differed between outcome groups and showed modest unadjusted discrimination, but neither demonstrated an independent association after adjustment. Given the few favorable outcomes, these exploratory findings are hypothesis-generating and require independent validation in larger cohorts.