Lactate dehydrogenase-to-albumin ratio and adverse outcomes in patients with HFrEF and HFmrEF

Objective This study investigated the association between lactate dehydrogenase-to-albumin ratio (LAR) and adverse outcomes in patients with heart failure with reduced ejection fraction (HFrEF) and heart failure with mildly reduced ejection fraction (HFmrEF). Methods This retrospective cohort study included 1,084 hospitalised patients with HFrEF or HFmrEF. It was approved by the Ethics Committee. Associations between LAR and endpoint events(HF-related readmissions, all-cause deaths, composite endpoints) were assessed using Cox regression, Kaplan–Meier curves, and restricted cubic spline analysis. The Fine-Grey model was applied for HF-related readmission to account for competing mortality. Subgroup and sensitivity analyses were performed to evaluate the robustness of the findings. Incremental predictive value of LAR was assessed using C-index, NRI, and IDI. Results During a mean follow-up of 29.3 months, higher LAR was independently associated with increased risks of HF-related readmissions(HR:1.602, 95% CI:1.088–2.359), all-cause mortality (HR:2.008, 95% CI:1.155–3.492), and the composite endpoint (HR:1.648, 95% CI:1.184–2.295) (all P < 0.05). Kaplan–Meier analysis confirmed the highest cumulative event incidence in the highest LAR tertile (Log-rank P < 0.001). Restricted cubic spline analysis revealed a nonlinear relationship between LAR and all-cause mortality, with risk significantly increasing at LAR ≥ 4.82 ( P -nonlinear < 0.001). The robustness of these findings was supported by multivariate subgroup and sensitivity analyses. Conclusion Baseline LAR level is an independent predictor of HF readmission, all-cause mortality, and the combined endpoint in both HFrEF and HFmrEF patients, demonstrating clinical value for risk stratification.