Evaluating the prognostic value of systemic immune‐inflammatory index in patients with acute decompensated heart failure

Abstract Aims The value of the systemic immune‐inflammatory index (SII) in assessing adverse outcomes in various cardiovascular diseases has been extensively discussed. This study aims to evaluate the predictive value and risk stratification ability of SII for 30 day mortality in patients with acute decompensated heart failure (ADHF). Methods This analysis included 1452 patients hospitalized for ADHF, all the participants being part of the China Jiangxi‐acute decompensated heart failure1 project. The risk stratification capability of the SII in patients with ADHF, as well as its correlation with the 30 day mortality risk among ADHF patients, was evaluated utilizing Kaplan–Meier survival analysis and multivariable Cox regression models. A restricted cubic spline was employed to model the dose–response relationship between the two, and the receiver operating characteristic curve was utilized to assess the predictive ability of SII for 30 day mortality. Results The Kaplan–Meier analysis revealed that the risk of mortality in the high SII group (SII ≥ 980 × 10 9 /L) was significantly greater than that in the low SII group (SII < 980 × 10 9 /L, log‐rank P < 0.001). After adjusting for various confounding factors, a higher SII was associated with an increased risk of 30 day mortality in ADHF patients hazard ratio (HR) = 2.03, 95% confidence interval (CI): 1.34–3.08. Further restricted cubic spline analysis revealed a non‐linear dose–response relationship between the two ( P for non‐linear = 0.006). Receiver operating characteristic analysis demonstrated that SII had a high accuracy in predicting 30 day mortality events in ADHF patients (AUC = 0.7479), and the optimal predictive threshold was calculated to be 980 × 10 9 /L, a sensitivity of 0.7547 and a specificity of 0.7234. Conclusions This study found a significant positive association between SII and 30 day all‐cause mortality in ADHF patients. We determined the SII cut‐off point for predicting 30 day all‐cause mortality in patients with ADHF to be 980 × 10 9 /L.