Inflammation plays a critical role in the pathogenesis of acute decompensated heart failure (ADHF), and circulating inflammatory cytokines have been implicated in heart failure pathophysiology and progression. However, their association with clinical outcomes in patients with ADHF remains incompletely understood.

A total of 872 patients with ADHF who completed 1 year of follow-up were included. Clinical characteristics and inflammatory cytokine levels were compared between patients with and without major adverse cardiovascular events (MACE). Multivariable Cox regression analyses were performed to identify factors independently associated with 1-year MACE. The incremental prognostic information of IL-2 beyond the established clinical risk factors was assessed using net reclassification improvement (NRI) and integrated discrimination improvement (IDI).

Serum interleukin-2 (IL-2) levels were significantly higher in patients with MACE than in those without MACE (0.24 pg/mL versus 0.21 pg/mL, P < 0.05). Multivariable Cox regression showed that log₂-transformed IL-2 was independently associated with 1-year MACE (HR = 1.212, 95% CI: 1.080-1.359, P = 0.001). Addition of IL-2 to the established clinical risk model significantly improved NRI (0.245, 95% CI: 0.015-0.370, P = 0.032) and IDI (0.019, 95% CI: 0.002-0.043, P = 0.028) for 1-year MACE.

Elevated circulating IL-2 levels were independently associated with adverse 1-year clinical outcomes in patients with ADHF and provided incremental prognostic information beyond conventional risk factors. IL-2 may have potential utility for risk stratification in ADHF.