Association between systemic inflammatory response index (SIRI) and all-cause mortality in patients with heart failure: a retrospective analysis based on the largescale clinical database MIMIC-IV

Background The Systemic Inflammatory Response Index (SIRI), a new prognostic biomarker, has been identified and shown to be associated with poor prognosis in many cardiovascular diseases. However, its relationship with heart failure is unclear, and the aim of this study was to investigate the relationship between SIRI and all-cause mortality in patients with heart failure. Method This study identified patients with heart failure admitted to the ICU from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database and categorized them into four groups based on SIRI quartiles. The primary study endpoint was 30-day all-cause mortality, and secondary study endpoints were 90-day, 180-day and 360-day all-cause mortality. A Cox regression proportional risk model was used to assess the risk of SIRI on outcome events, and restricted cubic spline (RCS) was employed to estimate the nonlinear association between SIRI and outcome events. Kaplan-Meier analysis was utilized to evaluate the relationship between SIRI and all-cause mortality in patients with heart failure. Subgroup analyses were performed to confirm the effect of SIRI on heart failure mortality in different subgroups. Result The study enrolled 6395 patients with a diagnosis of heart failure. After 30, 90, 180, and 360 days of follow-up, the mortality rates were 18.42%, 25.87%, 30.26%, and 35.76%, respectively. A Cox regression proportional risk model showed that after adjusting for the full range of possible confounders, it was found that the mortality rate was also higher in the group with high SIRI levels as compared to the group with low levels of SIRI (30-day: HR=2.39, and 95% CI = 1.91-2.98, P < 0.001 ; 90 days: HR = 2.25, 95% CI = 1.87-2.71, P < 0.001; 180 days: HR = 1.93, 95% CI = 1.63-2.29, P < 0.001; 360 days: HR = 1.88, 95% CI-= 1.61-2.20, P < 0.001). According to the Kaplan-Meier results, patients with higher SIRI had a significantly higher risk of all-cause mortality (P < 0.001). In addition, restricted cubic spline analysis showed a J-shaped (J-shaped) nonlinear relationship between SIRI and all-cause mortality in patients with heart failure. Subgroup analyses showed that SIRI did not interact with most subgroups, but the effect of SIRI on mortality was greater in the non-sepsis group. Conclusion SIRI was significantly associated with short-and long-term all-cause mortality in patients with heart failure and may become a predictor of prognosis in heart failure patients in the future.