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Background Aortic dissection (AD) is a highly fatal cardiovascular condition, with mortality exceeding 50% within the first 24 h and postoperative mortality approaching 30%. Inflammatory mechanisms have been implicated in AD pathogenesis, but the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) remains uncertain. This study aimed to synthesize available evidence on NLR as a predictor of adverse outcomes in AD and to inform hypotheses for future research. Methods Following PRISMA 2020 guidance, a systematic search was conducted in Web of Science, PubMed, Embase, and the Cochrane Library through December 2024. Study selection, data extraction, and quality assessment were performed independently by two reviewers. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using a random-effects model. Heterogeneity and potential bias were evaluated via subgroup analyses, sensitivity testing, and Egger's regression. Results Eleven studies (12 comparative groups) comprising 1, 792 patients were included (one publication reported two independent cohorts). Eelevated NLR was associated with increased mortality risk (pooled OR = 1. 16, 95% CI: 1. 05–1. 27, P = 0. 002). This association was significant in cohort studies (P = 0. 0005) but not in case-control studies (P = 0. 28). The result remained robust in leave-one-out sensitivity analyses. Substantial publication bias was detected (Egger's P 0. 0001). In patients with uncomplicated type B AD managed by endovascular intervention, elevated NLR predicted adverse events within two years (hazard ratio = 1. 98, P = 0. 015). Conclusion The evidence indicates that elevated NLR may serve as a potential independent predictor of mortality in AD, supporting its incorporation into risk stratification frameworks. Notwithstanding substantial publication bias—predominantly among smaller studies—sensitivity analyses confirmed the overall result stability. The observed prognostic value aligns with NLR's role in other vascular diseases, consistent with its interpretation as a marker of inflammatory burden. Generalizability is limited by the predominance of small Asian cohorts; therefore, multicenter prospective studies are required to validate these findings and to establish optimal NLR thresholds for individualized management. Systematic Review Registration https: //www. crd. york. ac. uk/prospero/displayᵣecord. php? RecordID=648318, PROSPERO CRD42025648318.
Li et al. (Thu,) studied this question.