Association between complement de-escalation and prognosis in sepsis: A systematic review and meta-analysis

Substantial evidence indicates that sepsis is accompanied by intense complement activation. This study aims to systematically evaluate the association between reduced complement activation levels and the prognosis in septic patients after treatment.

A meta-analysis was conducted in accordance with the PRISMA guidelines. The search databases included Web of Science, PubMed, the Cochrane Library, Embase, SinoMed, China National Knowledge Infrastructure, Wanfang, and VIP Database. The search timeframe spanned from the inception of each database to June 2025. Included studies were required to report cases with further reductions in complement activation levels following predefined treatments, while concurrently recording mortality and other biochemical indicators. Subsequently, a meta-analysis assessed mortality, inflammatory biomarkers (WBC, CRP, and IL-6), APACHE II scores, and indicators reflecting renal function (SCr and BUN) levels.

A total of 7,694 articles were retrieved, and 11 studies were ultimately included after screening. Although IL-6 (MD: -196.83; 95% CI: -329.16, -64.49; P < 0.001), CRP (MD: -9.09; 95% CI: -14.44 -3.74; P < 0.001) and APACHE II scores (MD: -4.55; 95% CI: -6.98 -2.12; P < 0.001) decreased significantly, reduced complement levels following multiple treatments in septic patients were not associated with lower mortality rates (RR: 1.04; 95% CI: 0.63, 1.71; P > 0.05). Additionally, there were no significant differences in WBC, SCr, and BUN levels.

The reduction in complement activation levels following treatment in septic patients is associated with disease severity scores and certain inflammatory biomarkers, but is not correlated with mortality.