Association of 41 circulating inflammatory factors, C-reactive protein, and procalcitonin with sepsis risk and 28-day mortality: A bidirectional Mendelian randomization and mediation analysis

BACKGROUND: The precise causal relationship between circulating inflammatory factors and sepsis has not yet been fully elucidated. OBJECTIVES: To identify biomarkers that enable earlier and more accurate diagnosis of sepsis. MATERIAL AND METHODS: The causal relationships between 41 circulating inflammatory factors, C-reactive protein (CRP), and procalcitonin (PCT) with sepsis and 28-day sepsis-related mortality were evaluated using two-sample bidirectional Mendelian randomization (MR) analyses. RESULTS: This study revealed negative causal associations between genetically predicted circulating inflammatory factors-interleukin-6 (IL-6) (odds ratio [OR] = 0.923; 95% confidence interval [CI], 0.854-0.998; p = 0.044), RANTES (OR = 0.926; 95% CI, 0.862-0.994; p = 0.033), and macrophage inflammatory protein-1β (MIP1β) (OR = 0.957; 95% CI, 0.919-0.996; p = 0.032) - and the risk of sepsis. Furthermore, positive causal relationships were observed between CRP and sepsis (OR = 1.140; 95% CI: 1.055-1.232; p = 0.001), as well as between CRP and 28-day sepsis-related mortality (OR = 1.241; 95% CI: 1.034-1.489; p = 0.020). Platelet-derived growth factor-BB (PDGF-BB) levels were also elevated in sepsis (OR = 1.136; 95% CI: 1.003-1.286; p = 0.044). Mediation analysis indicated that CRP mediated the effects of IL-6 and RANTES on sepsis, accounting for 25.87% (OR = 0.980; 95% CI: 0.961-0.998) and 2.04% (OR = 1.002; 95% CI: 0.991-1.012) of the total effect, respectively. The robustness of these associations was confirmed through leave-one-out sensitivity analysis and funnel plots. CONCLUSIONS: This study enhances our understanding of the mechanisms underlying sepsis and its associated mortality, and underscores the therapeutic potential of targeting inflammatory factors in its management.