Systemic immune-inflammation index predicted clinical outcome in patients with aortic stenosis

Background: Systemic immune-inflammation index (SII) is a novel inflammatory-related biomarker, and we aim to explore whether it can predict the poor prognosis of patients with aortic stenosis (AS). Methods The detailed data of patients with AS were extracted from the MIMIC-IV database. Restricted cubic spline (RCS) and COX regression analyses were used to reveal the potential association between SII and all-cause mortalities. Propensity score matching (PSM), inverse probability of treatment weighting (IPTW), and subgroup analyses were conducted to validate our findings. Receiver operating characteristic (ROC) analysis was performed to assess the performance of SII prognostic model. Results 839 patients were included in the study cohort. RCS analysis elucidated that the death risk of patients was gradually elevated with the increase of SII. Multivariate-adjusted 30-day (HR: 2.130; 95% CI: 1.167–3.885), 90-day (HR:1.644; 95% CI: 1.059–2.552) and 1-year (HR: 1.634; 95% CI: 1.136–2.350) all-cause mortalities were significantly higher in patients with high SII, which remained robust after PSM, IPTW, and subgroup analyses. The area under the ROC curve of SII (AUC: 0.727; 95% CI: 0.683–0.771) was superior to that of SOFA (AUC: 0.577; 95% CI: 0.525–0.629) and SAPSII (AUC: 0.681; 95% CI: 0.638–0.724) scores. Conclusion For patients with AS, SII was an independent predictor of elevated short-and long-term all-cause mortalities, with good predictive capability.