Day-7 lactate-to-albumin ratio as a prognostic marker in sepsis patients requiring prolonged mechanical ventilation: a multicenter retrospective landmark analysis of the Korean Sepsis Alliance registry.

Background: Prognostication in patients with sepsis requiring prolonged mechanical ventilation (MV) is challenging. While the lactate-to-albumin ratio (LAR) predicts early sepsis outcomes, its value during prolonged MV remains undefined. We evaluated the prognostic performance of the MV day-7 LAR in this population. Methods: This multicenter study retrospectively analyzed prospectively collected data [2019-2023] from the Korean Sepsis Alliance (KSA) registry. By a pre-specified day-7 landmark design, the analysis was restricted to adult sepsis patients who survived on MV to day 7 (requiring MV for ≥7 days). We compared the prognostic accuracy of day-7 LAR with days 1-3 LARs using receiver operating characteristic (ROC) curve analysis. Independent predictors of in-hospital mortality were assessed using multivariable logistic regression. We also evaluated the day-7 LAR's added value to the Sequential Organ Failure Assessment (SOFA) score. Results: Among 1,128 patients, survivors showed a significant LAR reduction by day 7 compared with non-survivors. The day-7 LAR demonstrated higher discriminative ability [area under the curve (AUC) 0.714] for in-hospital mortality than days 1, 2, and 3 LARs (AUC 0.600, 0.646, and 0.674). It also showed higher discrimination than procalcitonin and comparable discrimination to C-reactive protein (CRP). The day-7 LAR was an independent predictor of mortality [adjusted odds ratio 2.191, 95% confidence interval (CI): 1.626-2.952]. Adding the day-7 LAR to the day-7 SOFA score significantly improved predictive performance compared with the SOFA score alone. Furthermore, patients with a day-7 LAR ≥0.81 exhibited significantly lower survival rates and required more frequent organ-support therapies. Conclusions: In sepsis patients requiring prolonged MV, the day-7 LAR serves as a potential marker of the transition to non-resolving organ dysfunction and provides incremental prognostic value to the SOFA score. The day-7 LAR may offer a reproducible anchor for risk stratification and structured reassessment of therapeutic goals in this high-mortality population. These findings apply to patients surviving to the day-7 landmark and may not generalize to unselected ventilated sepsis populations.