Albumin-Based Biomarkers and Adverse Outcomes in Coronary Artery Disease: A Systematic Review and Meta-Analysis

Background: Albumin-based biomarkers have emerged as practical tools for prognostic assessment in coronary artery disease (CAD), but their comparative prognostic patterns and potential clinical utility have not been systematically evaluated. Methods: We performed a systematic review and meta-analysis of albumin-based biomarkers, including the C-reactive protein-to-albumin ratio (CAR/hsCAR), neutrophil percentage-to-albumin ratio (NPAR), lactate-to-albumin ratio (LAR), and C-reactive protein-albumin-lymphocyte (CALLY) index, in patients with CAD. Pooled associations with mortality and MACE were assessed, together with discriminative performance and clinical utility. Results: Thirty-four studies involving 47,763 patients were included. Higher CALLY values were associated with lower all-cause mortality (HR 0.46, 95% CI 0.24-0.87) and a directionally protective but non-significant association with MACE (HR 0.44, 95% CI 0.18-1.08). Elevated CAR/hsCAR was associated with increased mortality (OR 1.61, 95% CI 1.09-2.38) and MACE (HR 1.37, 95% CI 1.21-1.56) in acute coronary syndrome (ACS)-related cohorts. NPAR showed the most consistent association with mortality (HR 1.88, 95% CI 1.71-2.08; I² = 4.8%), whereas its association with MACE was less stable (HR 1.86, 95% CI 0.56-6.13). LAR showed the largest pooled effect estimate for mortality (HR 2.50, 95% CI 1.78-3.51). In discriminative analyses, CAR showed the most balanced performance for long-term MACE, NPAR showed the strongest rule-in profile for long-term MACE, and CAR and CALLY showed the best discrimination for mortality. Conclusions: Albumin-based biomarkers are linked to adverse CAD outcomes, especially in ACS, with distinct prognostic patterns by biomarker and endpoint. They provide complementary risk stratification information, and further prospective studies are needed to confirm their incremental clinical utility.