Systemic immune inflammation index with all-cause and cause-specific mortality: a meta-analysis

Area of Science:

• Immunology
• Epidemiology
• Public Health

Background:

• Inconsistent findings exist regarding the association between the Systemic Immune Inflammation Index (SII) and mortality.
• Understanding this relationship is crucial for public health and clinical practice.

Purpose of the Study:

• To investigate the association between SII and the risk of all-cause mortality.
• To explore the link between SII and cause-specific mortality, including cardiovascular disease (CVD) and cancer.

Main Methods:

• A comprehensive meta-analysis was performed, including literature searches of PubMed, Embase, Cochrane, and Web of Science up to March 1, 2024.
• Subgroup analyses and dose-response assessments were conducted to refine the understanding of mortality risk factors.
• The analysis included 33 articles comprising 427,819 participants.

Main Results:

• The meta-analysis found that a higher SII was significantly associated with an increased risk of all-cause mortality (HR=1.45, 95% CI [1.36, 1.54]).
• SII was also linked to a higher risk of CVD mortality (HR=1.44, 95% CI [1.29, 1.60]).
• A 100-unit increase in SII correlated with a 5% increase in all-cause mortality risk and a 6% increase in CVD mortality risk. No significant association was found with cancer mortality.

Conclusions:

• The Systemic Immune Inflammation Index (SII) is associated with increased all-cause and CVD mortality.
• Further basic research and data are required to validate these findings and elucidate the underlying mechanisms.