Abstract Background The systemic inflammatory response index (SIRI)—an inflammatory index derived from neutrophil, monocyte, and lymphocyte counts—has shown potential in predicting cardiovascular risk. However, its prognostic value in patients with acute coronary syndrome (ACS) treated with primary percutaneous coronary intervention (pPCI) remains unclear. This study was aimed at evaluating the prognostic significance of SIRI in this specific high-risk population. Methods We conducted a systematic search of PubMed, Embase, and The Cochrane Library up to June 2025 to identify all relevant studies about SIRI applied to patients with ACS after pPCI. The primary outcome was all-cause mortality. Among major adverse cardiovascular events (MACE), new-onset acute myocardial infarction (AMI), revascularization, and stroke were included as secondary outcomes. Risk estimates were pooled as odds ratios (OR) with 95% confidence intervals (CI). Results A total of nine studies involving 7679 patients were included. The pooled analysis demonstrated that an elevated SIRI was a significant predictor for both all-cause mortality (OR 3.32; 95% CI 1.29 to 8.54; p = 0.01), MACE (OR 2.45; 95% CI 1.74 to 3.45; p = 0.001), new-onset AMI (OR 1.86; 95% CI 1.25 to 2.77; p = 0.001), and myocardial revascularization (OR 1.64; 95% CI 1.35 to 1.98; p = 0.001). Conclusions Our meta-analysis demonstrates that an elevated SIRI is a useful predictor of all-cause mortality, MACE, new-onset AMI, and revascularization in patients with ACS undergoing PCI. As a simple and cost-effective index, SIRI shows significant potential for early risk stratification and may help guide clinical management in this patient population. Graphical abstract
Hu et al. (Mon,) studied this question.