Systemic Inflammatory Response Index Improves the Prediction of Postoperative Pneumonia Following Meningioma Resection
Meningiomas are among the most common tumors of the central nervous system, and surgical resection remains a primary treatment modality. Despite advancements in surgical techniques and postoperative care, postoperative pneumonia (POP) continues to be a significant complication following meningioma resection. The incidence of POP has not shown substantial improvement over the years, underscoring the need for better predictive indicators to identify high-risk patients early and implement preventive measures to enhance patient outcomes.
The systemic inflammatory response index (SIRI) is a novel inflammatory marker derived from peripheral blood neutrophil, monocyte, and lymphocyte counts. SIRI has been proposed as a tool to characterize the underlying inflammatory state and predict patient prognosis in various clinical settings. Given its potential, SIRI may serve as a valuable preoperative indicator to assess the inflammatory status of meningioma patients, identify those at higher risk of POP, and facilitate early intervention.
This study retrospectively analyzed the relationship between SIRI levels and the occurrence of POP in patients who underwent meningioma resection. Data from 282 patients who underwent meningioma surgery between 2008 and 2019 were collected from three participating hospitals. These patients had routine blood tests and SIRI measurements within one week before surgery. Inclusion criteria focused on patients undergoing their first meningioma resection, while exclusion criteria eliminated those with systemic infections, long-term use of hormones or immunosuppressive therapy, preoperative radiotherapy or chemotherapy, or previous craniotomy. The study was approved by the local ethics committees, and informed consent was obtained from all participants.
Comprehensive clinical data, including medical history, admission information, laboratory results, and treatment details, were collected for each patient. SIRI was calculated using the formula SIRI = neutrophil count × monocyte count / lymphocyte count. The primary outcome was the diagnosis of POP, which was based on guidelines from the Centers for Disease Control and Prevention (CDC) and the National Healthcare Safety Network (NHSN).
Statistical analysis was performed using R software. A logistic regression model was developed to evaluate prognostic factors for POP. The Delong method was used to compare the performance of different models based on the area under the curve (AUC). Multivariate models were constructed using backward stepwise regression, retaining variables with a univariate P-value < 0.05. Interaction terms were tested for all variables in the final model. The Kaplan-Meier method was used to assess the 30-day POP survival rate.
The study cohort included 282 patients, with 50 patients having an SIRI ≥ 1.85 and 232 patients with an SIRI < 1.85. The POP incidence was 20% in the high SIRI group compared to 3.4% in the low SIRI group. Univariate analysis identified age, SIRI, and white blood cell (WBC) count as significant predictors of POP. The optimal SIRI cutoff for predicting POP was determined to be 1.85 × 10^9 cells/L. Multivariate analysis confirmed that SIRI remained a significant predictor of POP, particularly in non-elderly patients (age 1.85, and SIRI demonstrated superior predictive performance (AUC: 0.874) compared to WBC (AUC: 0.794) and neutrophil-to-lymphocyte ratio (NLR, AUC: 0.767).
The Kaplan-Meier survival analysis revealed that non-elderly patients with an SIRI ≥ 1.85 had a significantly lower 30-day POP survival rate compared to those with an SIRI < 1.85. In contrast, no significant difference was observed in elderly patients. This suggests that the predictive value of SIRI is limited to non-elderly patients, likely due to age-related immune dysfunction in older individuals, which complicates the clinical course and increases the baseline risk of POP.
SIRI’s predictive power for POP was found to be better than that of WBC and comparable to NLR. The odds ratio (OR) for SIRI (1.500) was higher than that for WBC (1.139) and NLR (1.021). Additionally, SIRI demonstrated an excellent negative predictive value (NPV > 99%) in non-elderly patients, making it a valuable tool for identifying low-risk individuals who may not require intensive monitoring.
The study highlights the potential of SIRI as a simple and effective predictor of POP in meningioma patients. Its calculation is straightforward, relying on routine blood tests that are widely available and accepted in clinical practice. By combining neutrophil, monocyte, and lymphocyte counts, SIRI provides a comprehensive reflection of the body’s inflammatory state, which is particularly relevant for bacterial infections such as POP.
However, the study has several limitations. Its observational design means that the observed relationship between SIRI and POP could be influenced by confounding factors such as corticosteroid use or concurrent infections. Additionally, SIRI’s sensitivity may be limited in cases of viral infections, as it is primarily designed to reflect bacterial inflammatory responses. The study’s findings are also based on data from a limited number of centers, which may introduce selection bias due to regional differences in patient demographics and disease severity.
Despite these limitations, the study underscores the clinical utility of SIRI in predicting POP, particularly in non-elderly meningioma patients. Its superior predictive performance compared to traditional markers like WBC and NLR, combined with its simplicity and accessibility, makes SIRI a promising tool for improving postoperative care and resource allocation. For non-elderly patients with a low SIRI, reduced monitoring may be justified, allowing healthcare providers to focus resources on higher-risk individuals.
In conclusion, the systemic inflammatory response index (SIRI) is a valuable predictor of postoperative pneumonia following meningioma resection, particularly in non-elderly patients. Its predictive power exceeds that of traditional markers like WBC and NLR, offering a simple and effective tool for early identification of high-risk patients. By incorporating SIRI into routine preoperative assessments, clinicians can enhance postoperative care, reduce complications, and improve patient outcomes.
doi.org/10.1097/CM9.0000000000001298
Was this helpful?
0 / 0