Predictive Value of Perioperative Systemic Inflammation Response Index Dynamics for Postoperative Pulmonary Infection Following Esophagectomy: A Multicenter Retrospective Cohort Study.

BACKGROUND

Postoperative Pulmonary Infection (POPI) is a leading cause of morbidity and mortality following esophagectomy. Current static inflammatory markers lack the specificity to distinguish between surgical stress and early infection. This study aims to investigate whether the dynamic perioperative changes in the Systemic Inflammation Response Index (SIRI) can reflect the host's "inflammation-immune" balance and predict the occurrence of POPI.

METHODS

A two-center retrospective cohort study was conducted on 543 patients undergoing radical esophagectomy between January 2020 and November 2025. The SIRI Ratio was defined as postoperative (≤48h) SIRI divided by preoperative SIRI. Univariate and fully adjusted multivariate logistic regression models were performed. Diagnostic value was evaluated using ROC curve analysis, stratified by Neoadjuvant Chemoimmunotherapy (nICT) status.

RESULTS

The overall incidence of POPI was 29.7% (161/543). Patients with POPI exhibited a significantly lower SIRI Ratio (P = 0.002), indicating a blunted acute inflammatory response. Multivariate analysis identified the SIRI Ratio as an independent protective factor against POPI (OR = 0.98, 95% CI: 0.96-0.99, P = 0.037). Notably, a significant interaction was observed between nICT and the SIRI Ratio (P for interaction = 0.004). The SIRI Ratio showed better discrimination in the nICT-naïve subgroup (AUC = 0.776) but its diagnostic value was compromised in the nICT subgroup (AUC = 0.585).

CONCLUSION

Perioperative changes in SIRI were associated with POPI. The SIRI Ratio showed moderate discrimination overall, with better performance in patients who had not received nICT than in those who had.