Relationship between systemic immune-inflammation index and risk of mortality among pneumonia patients: a systematic
Ling Duan1, Zhuqing Zhang1, Yanggang Ou1
1Department of Infectious Diseases, The General Hospital of Western Theater Command, Chengdu, China.
Background:
The association of systemic immune-inflammation index (SII) with mortality risk in patients with pneumonia remains unclear now. This meta-analysis aimed to identify the relationship between SII and risk of mortality among pneumonia patients.
Methods:
Several databases were searched up to September 10, 2025. Odds ratios (ORs) and 95% confidence intervals (CIs) were combined and subgroup analyses by the study design (single-center vs. multi-center), location of occurrence [community-acquired pneumonia (CAP) vs. hospital acquired pneumonia (HAP)], etiology (viral vs. bacterial), severity of pneumonia (severe pneumonia), patient care setting (ward vs. intensive care unit), grouping method by SII (binary vs. continuous) and follow-up period (≤30 vs. >30 days) were performed.
Results:
Eleven studies with 2,841 cases were included with the mortality rate of 21.1%. Pooled results demonstrated that elevated SII was related to increased risk of mortality (OR =1.02, 95% CI: 1.00-1.05, P<0.001). Then subgroup analysis by the location of occurrence and etiology showed that the association between SII and risk of mortality was more significant among patients with CAP and bacterial pneumonia. Besides, subgroup analyses by the study design, severity of pneumonia, patient care setting, grouping method by SII and follow-up period further identified the association of SII with risk of mortality in pneumonia patients.
Conclusions:
SII might serve as a prognostic indicator in pneumonia and patients with elevated SII are faced with increased risk of mortality.
Related Concept Videos
Pneumonia I: Introduction
Pneumonia I: Introduction
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
Pneumonia III: Complications and Assessment
Pneumonia II: Pathophysiology
Factors Affecting the Risk of Infection
The integrity and count of the white blood cells help the body resist pathogens and fight infection. When impaired, it reduces the body's resistance to pathogens. The acidic pH levels of the gastrointestinal, genitourinary tracts, and skin create...
Pneumonia IV: Management
Bacterial Pneumonia Treatment
For bacterial pneumonia, antibiotics serve as the cornerstone of therapy. Initial treatment often begins with empirical antibiotics, tailored to the anticipated causative organism and adjusted based on culture results. Key antibiotic choices include:
