The Lactate/Albumin Ratio Predicts Mortality in Critically Ill Patients with Acute Kidney Injury: An Observational Multicenter Study on the eICU Database

Clinical significance of the lactate-to-albumin ratio on prognosis in critically ill patients with acute kidney injury

OBJECTIVE

To explore the relationship between lactate-to-albumin ratio (LAR) at ICU admission and prognosis in critically ill patients with acute kidney injury (AKI).

METHODS

A retrospective analysis was conducted. Patients were divided into low (<0.659) LAR and high LAR (≥0.659) groups. Least absolute shrinkage and selection operator regression analysis was conducted to select variables associated with the 30-day prognosis. Cox regression analyses were performed to assess the association between LAR and mortality. Kaplan-Meier curves were plotted to compare cumulative survival rates between high and low LAR groups. Subgroup analysis was employed to assess the stability of the results. ROC curve was used to determine the diagnostic efficacy of LAR on prognosis.

RESULTS

A nonlinear relationship was observed between LAR and the risk of 30-day and 360-day all-cause mortality in AKI patients (p < 0.001). Cox regulation showed that high LAR (≥ 0.659) was an independent risk factor for 30-day and 360-day all-cause mortality in patients with AKI (p < 0.001). The Kaplan-Meier survival curves demonstrated a noteworthy decrease in cumulative survival rates at both 30 and 360 days for the high LAR group in comparison to the low LAR group (p < 0.001). Subgroup analyses demonstrated the stability of the results. ROC curves showed that LAR had a diagnostic advantage when compared with lactate or albumin alone (p < 0.001).

CONCLUSION

High LAR (≥0.659) at ICU admission was an independent risk factor for both short-term (30-day) and long-term (360-day) all-cause mortality in patients with AKI.

Impact of lactate/albumin ratio on prognostic outcomes in patients with concomitant heart failure and chronic kidney disease

Previous studies have linked the lactate/albumin (L/A) ratio to poor outcomes in various conditions, but its connection to mortality in patients with both heart failure (HF) and chronic kidney disease (CKD) remains unclear. Using data from 1537 patients in MIMIC-IV, this study examined the relationship between L/A ratio and in-hospital and one-year mortality, employing Cox models, Kaplan-Meier (KM) analysis, and restricted cubic splines (RCS). The non-survivor group showed higher L/A ratios than survivors (1.04 ± 0.78 vs. 0.58 ± 0.29, p < 0.001), indicating a significant link between higher L/A ratios and mortality. Cox analysis identified the L/A ratio was significantly related to all-cause mortality both in-hospital (HR 2.033; 95% CI 1.576-2.624; p < 0.001) and one-year (HR 1.723; 95% CI 1.428-2.078; p < 0.001). The association between L/A ratio and mortality was non-linear and increasing. The KM survival curves demonstrated significantly poorer survival outcomes for the high L/A group compared to the low L/A group, a difference that was statistically validated by a significant log-rank test (log-rank p < 0.001). L/A ratio has a significant association with poor prognosis in patients with HF and CKD patients in a critical condition. This finding demonstrates that L/A ratio might be useful in identifying patients with HF and CKD at high risk of all-cause death. Further large-scale prospective studies are needed to verify these results and inform clinical decisions.

Prognostic value of serum lactate level for mortality in patients with acute kidney injury

BACKGROUND

Serum lactate is associated with mortality in diverse kinds of patients. This study aimed to investigate whether serum lactate level may independently predict mortality in acute kidney injury (AKI) patients.

METHODS

A total of 4461 AKI patients were collected from the Medical Information Mart for Intensive Care (MIMIC III) database and followed up for 365 days. According to serum lactate tertiles, participants were divided into three groups (Q1-Q3) by: Q1 ≤ 1.60 mg/dl, Q2 = 1.61-2.70 mg/dl, and Q3 ≥ 2.71 mg/dl. We calculated the hazard ratio (HR) and 95% confidence intervals (Cls) for mortality across each tertile of lactate by using the Q1 as reference and constructed four models to adjust for the HR of mortality.

RESULTS

Nonsurvivors had significantly higher lactate compared with patients in the survival group. Mortality rate gradually elevated with the increase in serum lactate level (Q1: 29.30%, Q2: 33.40%, Q3: 37.40%). When compared with Q1 after adjustment of all confounders, the HRs of Q3 still was 1.20 (95% Cl 1.05-1.37).

CONCLUSIONS

This study demonstrated that high serum lactate levels were an independent predictor of mortality in AKI patients.

[ROC curves: general characteristics and their usefulness in clinical practice]

The use of diagnostic tests to determine the presence or absence of a disease is essential in clinical practice. The results of a diagnostic test may correspond to numerical estimates that require quantitative reference parameters to be transferred to a dichotomous interpretation as normal or abnormal and thus implement actions for the care of a condition or disease. For example, in the diagnosis of anemia it is necessary to define a cut-off point for the hemoglobin variable and create two categories that distinguish the presence or absence of anemia. The method used for this process is the preparation of diagnostic performance curves, better known by their acronym in English as ROC (Receiver Operating Characteristic). The ROC curve is also useful as a prognostic marker, since it allows defining the cut-off point of a quantitative variable that is associated with greater mortality or risk of complications. They have been used in different prognostic markers in COVID-19, such as the neutrophil/lymphocyte ratio and D-dimer, in which cut-off points associated with mortality and/or risk of mechanical ventilation were identified. The ROC curve is used to evaluate the diagnostic performance of a test in isolation, but it can also be used to compare the performance of two or more diagnostic tests and define which one is more accurate. This article describes the basic concepts for the use and interpretation of the ROC curve, the interpretation of an area under the curve (AUC) and the comparison of two or more diagnostic tests.

Association of lactate/albumin ratio with in-hospital mortality in ICU patients with acute respiratory failure: A retrospective analysis based on MIMIC-IV database

We aimed to investigate the association between the lactate/albumin ratio (LAR), and in-hospital mortality in critically ill patients with acute respiratory failure. This retrospective cohort study was conducted based on the medical information mart for intensive care-IV database, which included critically ill adult patients with acute respiratory failure whose primary endpoint was in-hospital death. The analyses included curve fitting, a logistic multivariate regression model, and subgroup analysis. In this study, 6028 intensive care unit patients with acute respiratory failure were analyzed. Of these, 1843 (30.57%) died. After adjusting for confounding factors, a nonlinear relationship between LAR and in-hospital mortality was observed, and the risk of death was found to decrease by 81% with a reduction of 1 unit of LAR when it was < 4.46. The association between LAR and in-hospital mortality was not statistically significant when LAR was > 4.46. Hence, the relationship between LAR and in-hospital mortality could only be observed when the LAR was < 4.46. There is a nonlinear relationship between LAR and the risk of in-hospital death in intensive care unit patients with acute respiratory failure, and there is a saturation effect.

Comparison of lactate/albumin ratio to lactate and lactate clearance for predicting outcomes in patients with septic shock admitted to intensive care unit: an observational study

The aim of this study was to evaluate the prognostic value of the Lactate to Albumin (L/A) ratio compared to that of lactate and lactate clearance in predicting outcomes in patients with septic shock. This was a multi-center observational study of adult patients with septic shock, who admitted to intensive care units (ICUs) at Shohada and Imam Reza Hospitals, Tabriz, Iran, between Sept 2018 and Jan 2021. The area under the curve (AUC) of receiver operating characteristic (ROC) curve and multivariate logistic regression analyses were used to explore associations of the L/A ratio, lactate and lactate clearance on the primary (mortality) and secondary outcomes [ICU length of stay (LOS), duration of mechanical ventilation (MV), need of renal replacement therapy (RRT) and duration of using vasopressors] at baseline, 6 h and 24 h of septic shock recognition. Best performing predictive value for mortality were related to lactate clearance at 24 h, L/A ratio at 6 h and lactate levels at 24 h with (AUC 0.963, 95% CI 0.918-0.987, P < 0.001), (AUC 0.917, 95% CI 0.861-0.956, P < 0.001), and (AUC 0.904, 95% CI 0.845-0.946, P < 0.001), respectively. Generally, the lactate clearance at 24 h had better prognostic performance for mortality and duration of using vasopressor. However, the L/A ratio had better prognostic performance than serum lactate and lactate clearance for RRT, ICU LOS and MV duration.