Prognostic significance of the advanced lung cancer inflammation index in acute coronary syndrome patients: a systematic review and meta-analysis

Background Acute coronary syndrome (ACS) outcomes are strongly influenced by systemic inflammation and nutritional status. The Advanced Lung Cancer Inflammation Index (ALI) integrates both aspects in a single metric. Originally developed in oncology, ALI is based on BMI, albumin, and the neutrophil-to- lymphocyte ratio and is now being evaluated in cardiovascular cohorts. This meta-analysis assesses the prognostic value of ALI in ACS. Methods We searched PubMed, Scopus, and Google Scholar through September 2025 using a PRISMA-compliant approach. Studies evaluating the association between ALI and ACS outcomes were included. Binary random-effects models were used to estimate pooled odds ratios (ORs). Heterogeneity was measured with I2 statistic. Results Of 36 records, 8 studies (11 cohorts) were included for qualitative synthesis, and 6 studies (9 cohorts) contributed to the quantitative meta-analysis, encompassing 8,397 ACS patients from China, Italy, and Turkey. The included studies were prospective or retrospective cohorts. Pooled analyses showed that patients with low ALI had a significantly higher risk of mortality compared with those with high ALI (HR 2.76, 95% CI 1.92-3.95, p < 0.01), with low between-study heterogeneity (I2 = 11.3%). Similarly, low ALI was strongly associated with an increased risk of major adverse cardiovascular/cerebrovascular events (MACE/MACCE) when analyzed as a categorical variable (HR 2.37, 95% CI 1.87-3.01, p < 0.01; I2 = 0%). However, when ALI was analyzed as a continuous variable, no significant association with MACE/MACCE was observed (HR 0.98, 95% CI 0.96-1.00, p = 0.08), with high heterogeneity (I2 = 94.1%). Discriminative analyses showed that ALI had moderate predictive accuracy for mortality (AUC 0.72, 95% CI 0.67-0.78, I2 = 86.3%) and for MACE/MACCE (AUC 0.68, 95% CI 0.63-0.73, I2 = 83.2%), though heterogeneity was high for both. Conclusion ALI is a robust prognostic biomarker for adverse outcomes in ACS, particularly when applied categorically, while its role as a continuous measure remains uncertain due to heterogeneity. Further prospective studies with standardized cut-offs are needed to clarify mechanisms and confirm clinical utility.