Nonlinear Relationship Between Lactate/Albumin Ratio and 28‐Day ICU Mortality in Patients With Congestive Heart Failure: Insights Into Inflammatory and Metabolic Interplay

BACKGROUND: Congestive heart failure (CHF) among critically ill patients is a significant cardiovascular disorder that is linked to elevated mortality rates. The lactate/albumin ratio (LAR) is a readily available clinical metric that may provide valuable information regarding the metabolic and nutritional conditions. However, its association with mortality in patients with CHF remains unexplored. This study aimed to investigate the association between LAR and 28-day intensive care unit (ICU) mortality among critically ill patients with CHF. METHODS: Using the eICU Collaborative Research Database (eICU-CRD), this study was retrospective and observational. The study included those admitted to the ICU with a preliminary CHF diagnosis. The nonlinear relationship between LAR and 28-day mortality was assessed using multivariate Cox regression and generalized additive models (GAMs), with confounders adjusted, and the crucial LAR value was identified through threshold effect analysis. RESULTS: Among 2117 patients diagnosed with CHF, 291 (13.7%) died within 28 days of ICU admission. A nonlinear relationship was observed between the LAR and mortality. For LAR values under 1.65, each unit increment was associated with a 2.41-fold increase in the likelihood of mortality (p < 0.001). Nonetheless, this link was not significant for LARs ≥ 1.65 (HR = 1.14, p = 0.111). Subgroup analyses validated the robustness of this nonlinear relationship, except for a significant interaction with the respiratory rate. Mediation analysis revealed that white blood cell (WBC) counts partially mediated the link between LAR and mortality, suggesting potential connections between metabolic disturbances, inflammatory pathways, and adverse outcomes in this population. CONCLUSIONS: LAR was nonlinearly related to 28-day ICU mortality, identifying a particular turning point in critically ill patients with CHF. These findings suggest that the LAR, a readily available clinical metric, may help identify high-risk patients with CHF and inform clinical management strategies.