Evaluation of systemic immune inflammation index as a predictor of lethal outcome in patients with thoracic empyema.

Purpose: No study to date has investigated the prognostic ability of the recently introduced "systemic immune-inflammation index" (SII) in thoracic empyema. Therefore, we aimed to evaluate the association between SII and outcome in such patients. Methods: The single-center retrospective study involved 84 patients with thoracic empyema admitted to the Clinic of Thoracic Surgery at a University Hospital Stara Zagora between January 2021 and October 2023. Clinical and laboratory parameters were recorded at admission. We analyzed the area under receiver operating characteristics (AUROC) curves of SII, qSOFA, and SIRS and compared their prognostic value. Results: The observed in-hospital mortality was 10.7%. As a predictor of death, SII showed the best prognostic ability compared to SIRS (AUROC = 0.782 vs. 0.676) and qSOFA (AUROC = 0.782 vs. 0.747). At the optimal cut-off value of > 3269 x 109/L, we identified a sensitivity of 71.4% and a specificity of 78.7%. Conclusion: In thoracic empyema, SII could be routinely used as a simple, low-cost, and easily assessable indicator for patients at higher risk of poor outcome. [ABSTRACT FROM AUTHOR]